As an engineer (not in the aviation industry), I want to add that it's true that a fault that appears to be same might have have different causes, BUT if the same part keeps having problems and you are fixing it time and time again and always something new pops up, then you sometimes want to scrap that part entirely and design it from scratch again - ideally, using a different engineer. Oftentimes 80% of the problems are located in 20% of the parts and if you already found that you have a part at hand which keeps suffering all sorts of problems, there might be more to discover in this part. And then it might be cheaper and safer to scrap it and start designing this part from scratch again.
This is what an effective Failure Reporting and Corrective Action System (FRACAS) is supposed to do. Find the root cause of the failure, determine a corrective action to fix the root cause, and then, in a step that is rarely correctly implemented, evaluate the effectiveness of the fix. After the second incident at the latest Airbus should have performed an extensive FMECA leading to failure mitigation redesign if the NLG and SW systems.
Agreed, 90% of the time we even know the system was badly designed, but it is too expensive to redesign something in production so in go the workarounds.
On the other hand the A320 is one most-built passenger planes and seeing use in the EU it might even do more starts and landings than the 737, which will increase the number of incidents. But yes, getting fresh brains on this, maybe not to redesign but to test its limits in creative ways, would help, but on the other hand: The A320 not even lands with a 90 degree wheel but will even start with one.
I think the most important take away from all of these incidents is that the nose gear has not collapsed after landing 90 degrees to the side like this. I don't know how close to collapse they've been, but they haven't collapsed. That speaks volumes to just how incredibly strong those struts are.
It seems like 90 degrees is a default position by design. Any other position between 0 and 90 would cause the plane to veer off the runway which could be a potentially dangerous situation.
Interesting point, I'm going to guess keeping the landing gear steady at 0 degrees will be much harder to do. It is curious that in these incidents, it didn't collapse. I found this part especially impressive. My uneducated guess would have been the forces would have been great enough to rip the landing gear right off.
@@notsam498 Landing gear is one of the strongest and toughest parts of a commercial aircraft, second only to turbine blades. Tyres and even wheels wear surprisingly easily compared to the strength of the gear and its mountings. If gea R gets ripped off, you know it was a oarticularly hard impact.
I remember JetBlue 292. I watched it live, and also remember passenger interviews stating, "It was one of the smoothest landings I ever experienced." This just puts on display the pilots' skill level with events like this over the years...
I would be interested to know how the design of this nose wheel system differs from similar planes, as well as some design engineer's comments regarding the A320's design. So many problems with a single system leads to obvious questions.
I agree. It does seem like an absurd number of incidents with the same resulting issue, regardless of the cause being different. It really does seem like some kind of design issue.
Keep in mind, we’re focusing on a narrow subset of the total set of problems these aircraft experience. This cannot be the only component on the aircraft to fail. That said, how serious are these nose gear failures? How many lives lost? How many airframes destroyed? How many people crippled or seriously injured? How much total $ in losses - destroyed equipment, maintenance time, lost flying time, etc? Keep in mind, I can point to video of an aircraft, at the gate, engines off, exploding because someone failed to replace a washer during maintenance (No, not nose gear - if memory serves, it was part of the slats extension mechanism). With the vast array of parts, systems, etc, on aircraft, designers need to pick & choose which failure modes to design out, which are unpleasant, but still the lesser of evils, and which are not worth their time (because there are bigger problems to tackle).
I realize how seriously this could have gone wrong, but there's something inherently funny about Airbus going on a Wile E Coyote like chase after the nosewheel that keeps going wrong in increasingly unlikely ways.
"okay we have made it completely impossible for the nose gear to rotate 90 degrees before landing" "sir I've just received a report that a nose gear has rotated 90 degrees before takeoff"
For me it's the fact that by the 3rd time, the pilots's reaction was essentially: "We're getting warnings about steering aren't we?" "Yup" "The nose wheel has turned 90 degrees hasn't it." "Most likely" "We're going to have a pain landing aren't we." "Definitely."
Sounds quite crazy that you could dispatch with any fault in nose gear. I would not like to be inside such plane. Luckily it seems to be amazingly tough thing. Once in Helsinki-Vantaa a van got knotted around main gear with no problem.
@@FL0RiaN94 I think that they didn't notice the nose gear during takeoff, because of the momentum of the plane possibly forcing the wheels into the correct position, but once the pressure was off the wheels, they popped into the 90° angle that they wanted so badly. Pilots maybe thought some unexpected sidewind or whatever, instead of a stubborn nose?
I love these videos and they are always very professionally presented. Just one little point - the editing is so good that it sounds like Peter never stops to take a breath. Sometimes a few seconds pause as happens in normal conversation or even a lecture, allows the listener to take in and process what has just been said. Just a thought! :-)
I would blame You Tube as they always want videos cut down to the shortest possible time it seems. So it might be a case of having to talk quicker so everything can be included in the video?
"how they didn't notice that, I'm not sure," sounds like a very polite way to say something significantly less polite. I'm actually laughing at that that sounds. Your explanations are still awesome to enthusiasts like me. Glad to see you're still absolutely fantastic!
maybe theirs a lock on the wheel that locks it into position, that broke and given the direction of the aircraft and how it was moving, allowed the wheel to rotate forward in the general direction of the aircraft's movement and allowed them to proceed with the takeoff normally until they got it in the air and put it down and the force of the resistance of the air on the wheel jammed it in the most inaeordynamic way
Capt on A320, now retired, 1200 hours command, on type, my experience of nose wheel problems, was as follows. Half way thro a take takeoff, nose wheel commanded 45 degrees left.full right rudder applied, To get back near the runway centreline. T/O continued. Inquiry stated unknown fault of BSCU. Previously, the company had a similar fault, crew rejected the T/O and the aircraft had a runway excursion. BSCU issue, again.
The different modes of failure leading to the same result reminds me of HVAC service calls I've been on. "My air isn't cooling 'again'". Then I get there to find a totally different failed component than the time before. But trying to get some rental property tenants to understand that can be challenging.
You get this situation in any technical field. I used to do TV repair. Any one of a hundred parts could cause loss of sound. As far as the customer is concerned its the same fault every time. What you do is build in a bit extra in your standard pricing, so that when luck brings you back to the same customer with the same symptom(s), you can fix it for free and retain the good will. You cannot expect customers to understand technical detail. When you fix faults you should also do basic checks that usually will reduce the probability of a callback. My car was leaking coolant, so I took it to the dealer. The mechanics spotted that a hose was weak so they replaced it. But next day it still leaked coolant. This time they identified another dodgy hose. They considered that a separate fault and wanted to charge me full parts and labour again. My view was that if they were competent, once they found one dodgy hose, they should have checked ALL hoses - after all they were all equally old. So I offered to pay for the extra part cost but not the extra labour, as the labour in the first job I had already paid for turned out to be not properly done. I had to fight for that one though. But if it was coolant leak problem and next day a brake fault, then clearly the faults are unrelated and the customer should pay for two different lots of parts and labour in full.
What kind of repairs have to be done to the runways after these types of landings? I imagine that they cause a fair amount of damage to the surfaces of the runway. Great video by the way.
I'm actually impressed you can grind off half a nose wheel while having the weight of a jet aircraft pressing down on it without any visible damage to the runway. Amazing material!
The nosewheel supports less than half the weight of the aircraft (maybe around 25%?). Still it's significant weight. But the fact that the wheel ground away so much says how much harder the concrete is compared to the aluminum of the wheel.
@@rnreajr9184 Another commenter said it was a maximum of 4 tons of pressure on the nosewheel (out of 65 tons, overall weight). I don't know how accurate he was being, but if that's the case, it's a lot less than 25% of the weight. This wouldn't surprise me, based on the some photos I've seen of large commercial aircraft tipping and falling onto their tails with improperly loaded cargo or even because of the horizontal stabilizer being blanketed with volcanic ash (which happened to a lot of parked aircraft during the Mt Pinatubo eruption in the Philippines).
@@skyhawk_4526 Yeah I saw the comment. He claimed the nose gear takes about 10% of the landing weight. Still very impressed that with multiple similar incidents, the nose gear holds up. Scary stuff, but an amazing testament to the integrity of a moving structural part.
@@skyhawk_4526 That wasn't 4t of weight on the nose wheel: it was a 4t friction force due to friction between the nose gear and runway. (The weight is a downward force; the friction is backwards.)
I wonder if Airbus has done any major redesign of these systems for the Neo since it kinda seems "too easy" for the landing gear getting stuck like that for a variety of reasons
Yes, the company designing and manufacturing the nose landing gear changed its name from Messier-Bugatti-Dowty to Safran Landing Systems. That should do the job. Right?
While there are differences, there is still a theme somewhat, in part including bad maintenance. Hopefully they've worked out the rest of the bugs. The main outlier would seem to be power washing. Instead of reemphasizing "don't do that!", it seems to me to be better to redesign to withstand it if possible.
I remember when it seem like a rash of Boeing 727 (yes, I'm that old!) had issues with their nose gear Not Extending when they came in for landing! I think that there might have also been a few cases with the nose gear extending but not locking in the down position... I Do remember when one pilot was able to trim his airplane to such an extent that he was able to keep the nose of the jet off the ground until he was going (what seemed to be) about 6mph (10kph) and the nose came down reasonably slow!
I am not surprised by this as I spent over 40 years working for a major Avionics manufacturer. A fault would be flagged and something totally unrelated would be causing fault and not fault that was flagged.
Sometimes the computer in my car will display several fault codes at once. Repair shops like to estimate the cost of repair based on EVERY fault code, and add them all up for the grand total. I bought a factory service manual and studied the relationships between different systems and can pretty much zero in on the problem. I think some of these automotive systems are overly complex, so I can only imagine how complicated aircraft systems must be.
@@RetNemmoc555 Interesting I did exactly the same thing with my MR2 Spyder. The factory repair manuals for this car are 4 inches stack! I just can't imagine the work load on a commercial airliner when things go South.
@@RetNemmoc555 Yes aircraft systems are much more complicated than automobile systems. But the basics are still the same and there is an interrelationship between systems no matter where they are used and sometimes its not that easy to diagnose what the problem is! Yes they are putting in systems that are way to complex for there own good. they need to use the KISS principle. Keep it Simple Stupid!
If you want to see the most reliable, concerned for the customer, knowledgeable auto mechanic, you ought to check out TH-cam videos from Rainman Ray who lives and works in Florida. He often not only explains why auto systems are so complex, but how complete a professional code scanning system can examine and manipulate virtually all the systems in modern automobiles.
I can understand that all these are different failures, hovewer it is obvious to me that there should be design review and some is still wrong here. Typically some mechanical locks are used to block gear in default position in case of controls failure. This should be implemented here.
I'm pretty sure that the 320 rotates the landing gear to the 90 degree mark before stowing. That said, if there is a failure then the nose gear is already locked at 90 so as to prevent a more serious landing problem of a misaligned front wheel such as in the case where the locking pins were sheared off.
The majority of these faults would not be fixed by a lockout as the computer would have unlocked the gear before a fault is triggered. Then there is a problem of a lock adding another point of failure vs how many failure points are present.
Every other airplane on Earth with a nosewheel oleo strut has what you’re talking about: a nosewheel centering cam. It works off the extension and compression of the strut. When the airplane is in flight, there is no weight on the gear, so the strut is fully extended, which engages the cam and straightens the wheels. When the airplane lands, weight on the strut forces it to compress and disengages the cam, allowing the nose strut to rotate for steering. How and why Airbus designed their steering without a simple, mechanical, industry standard safety mechanism and managed to get it certified is beyond my understanding.
@@Tony-Waldron I thought so as well, at least I thought I had seen that and assumed it would need a less deep wheel well, but that must have been a differnt type of aircraft. I looked it up and in a video where they executed a gear retraction test during maintenance with the aircraft jacked up, it went up with the wheels straight. Also there seems to be a braking plate on the top of the well, to stop the tires from turning after retracting the gear.
Two thoughts -- 1) I'm constantly impressed by the ability to identify how such failures occur; 2) if the nws has so many different ways to fail, maybe a complete redesign is in order?
Very good presentation. Just one comment: The A320 doesn't have a Standby BSCU. The BSCU is a dual channel unit and channels are swapped by cycling the AS/NWS Switch. Late model A320s have an Alternate Brake Control Unit (ABCU) that is not associated with nose wheel steering.
According to Airbus's Safety first report titled "Landing with Nosewheels at 90 degrees" , this is what is written for the 2007 NWS 90 degree incident "An updated design was introduced to improve the robustness of the BSCU and to allow a switch-over to the passive BSCU system when the outputs of the active BSCU system become frozen (i.e. switch from BSCU 1 to BSCU 2 or vice versa)." You can search for the document on Google. or on Airbus Safety first website.
One of the MANY reasons I watch your interesting videos is the incfedible similarity between modern airplanes and IT systems (meaning endpoints, servers, network, storage, you name it). I work as system administrator in one of the most complex possible environment (a network of cruise ships) Both are a sum of many very complex systems and very often improvising or going with "post hoc ergo propter hoc" is the first step to failure. Many users tend to simplify the problems because they don't have the "big picure" of the situation, is human and it happens with computers as well as with airplanes. Keep doing this videos Petter, they teach more than you can imagine to us IT flight enthusiasts, thank you!
Firstly I imagine and Airbus 320 pilots must get this event included in their simulator training. If not it should be. Secondly are their any other systems that are this problematic in both number and variety of causes? on any other common airframe? Finally, has this become a some sort of fatalistic joke in airbus pilot circles?
If there are similar failures occurring in other systems on other types and makes of aircraft, we'd be the last to know. Such things are only made public when there's no way to hide them.
@@EleanorPeterson You don't understand the industry very well. When things go wrong with planes it's impossible to hide them. Much too many people involved
@@Stettafire you don't understand aircraft very well. When things go wrong with a plane and you are inside of it, it is very unlikely you would ever find out that there actually was something wrong, because of how much redundancy there is and how large the safety margins are.
@@EleanorPeterson All significant failures and occurrences leading to actual or potential damage or injury are reported publicly, in any civilised country. The UK's, for example, are here www.gov.uk/government/collections/air-accident-monthly-bulletins
Yet another wonderful and informative video with straight talking explanations for the different reasons that this keeps happening yet for different reasons, you really do give better information than anyone I can think of, you really should have your own television programme where you explain all of these questions to the public at large. Flying is an everyday event for many people, yet we know so little about it, it's taken for granted, there have been others before you but in different fields of expertise who explain in detail how and why certain things just are, you are another one of these people, you have a fantastic gift and you deserve more than being on TH-cam. Take care and stay safe :)
I understand your sentiments about Mentour Pilot being on television. However, being on TH-cam is better than traditional television. If these programs were on traditional television, many would not be able to watch the shows because they would not have the particular channel in their cable TV subscription package. In addition, there would be issues with location, as the channel would only be available in select countries. Furthermore, many people have cancelled their traditional television service, so they would not be able to watch. With TH-cam, generally people anywhere in the world can watch Mentour Pilot at any time they want. TH-cam offers translation via closed-captioning, so even non-English speakers can still learn from the programs. In addition, TH-cam videos can be viewed by many different devices, such as computers, smartphones, tablets, Roku boxes, Apple TVs, and even smart televisions. That is, you can watch TH-cam videos on a television. Plus, TH-cam promotes two-way communication via the comments, while traditional television is only one-way communication. Mentour Pilot going to television would be a downgrade, sort of like going from piloting a Boeing 737 to a single-engine Cessna.
The RAT automatically deploys with the loss of AC Bus 1 and AC Bus 2. As mentioned above, if the APU is started then everything is powered and you don't get the RAT automatically.
Somewhere in Airbus someone is rolling their eyes and going "okay how else did the nosegear guys manage to mess up" :-)! Seriously it seems that there are lots of things that happen to have an outcome of the nosegear being rotated 90 degrees left. Still it's surprising to have this many problems compared with everything else - I suppose the nosegear does take quite a pummeling every landing. It does sound like Airbus need to put a checklist into place for landing with nosegear at 90 degrees and all green indications it they're not going to allow the landing gear unsafe checklist (or just say you can use it - which would seem to be the most sensible).
well TBF some of these are related to the design fault, while some are related to maintenance procedure fault. as for maintenance procedure its result of airlines outsourcing maintenance to save costs and idiots getting the job to maintain multimilion dollar airliners.
@@kopazwashere yes, actually my comment was somewhat tongue in cheek :-)! Actually I think these events show how well the nosegear was designed - probably to deliberately fail to a 90degree rotation which despite damage to the wheels/tyres enables a straight landing to be made.
Seems to be a fundamental problem with the design of the gear itself, do we see similar problems happening for random reasons on other models of aircraft?
That was what I was thinking too. On the other hand, maybe you should look at the number of incidents vs the number of flights that passed without incident. In principle, every incident is one too many, but maybe the number of incidents is statistically not very significant. But I got the same idea basically. If there are so many incidents, there might be a fundamental design flaw in the system.
@@0Synergy Yeah, sure, but that doesn't mean it can't be a design flaw. If the design allows for such mistakes, it's the design, not the people making the mistakes. You should design stuff with crucial functions in a way thay can't be mounted incorrectly. And if water is no good for the device, take measure water can't penetrate. Obviously, if you want to sabotage somthing, you can always find a way to mess things up. But it shouldn't be made too easy. I don't know all the inns and outs of this system, but the fact that there's a video about these accidents, incidents and near accidents, means that there is something going on. There are no videos about Boeings nose gear failures... So, unless Mentour is making sensation, there IS something about this gear.
I'm amazed that there have been so many incidents with the nose gear of this plane. Would it be practical to redesign the whole nose gear from scratch?
@@hansloyalitat9774 component modifications & upgrades on airliners happen a lot more than you think. The timeframe for having to make a change could be anything from “next overhaul/heavy check” to “don’t fly until it’s changed” it all depends on how important the component is and how bad the fault is. It’s for this reason that a lot of major components like landing gear and engines are leased from a 3rd party.
@@hansloyalitat9774 The reason they have not redesigned the whole nose gear is because no one has died YET. Airbus is going through a grace period right now. However, if people die, then the cost will be quite high because they will have to ground all A320's until they are safe to land, will have to compensate the families of the dead, do a costly investigation, and then do a major redesign and costly retrofit. Airbus would be smart to do a complete redesign now, but we all know that won't happen, meanwhile they will just keep doing band-aid repairs and betting against the unthinkable.
As far as Ik the 737 doesn’t perform this autotest. However the steering mechanism on the 737 (at least since the NG as the gear went through a redesign during development) has a different locking system, though I could be wrong there. And to be fair I don’t know if any 737 had this gear rotation 🤷♂️
The 737 is still using cable controlled, hydraulically actuated system and got plenty of mechanical stops, even for the MAX. direct control from the captain side. no such test.
I am a Reliability Engineer working in this type of air vehicle development. When you design such complex hardware/software systems it is crucial to perform a comprehensive Failure Modes, Effects, and Criticality Analysis (FMECA) in concert with the mandatory Safety Critical Thread Analysis (SCFTA). In the past these analyses were led by the Reliability Engineer who was performing the FMECA with the Safety Engineering function developing the SCFTA with Software Engineering support. As the US has dropped mandating the use of Military Standards in many areas (a result of Acquisition Reform in the 1990s) the level of rigor (yes I am American so US English used here) of these analyses has been left up to the manufacturer for the most part. One result of letting the bean counters determine resources while also removing mandatory processes which require collaboration is that many companies have decreased the rigor of their Reliability analyses including the FMECA coverage and depth while somewhat stovepiping the SCFTA analysis efforts into the Software development process with System Safety supporting Software Engineering. It is clear that this structure is almost certainly in place at Airbus given the various failure modes discussed in the video that resulted in the NLG being rotated 90 degrees. Identifying, analyzing, and mitigating these failure modes is the MAIN reason for the FMECA. An investment in real FMECA analysis coordinated with the SCFTA activities would have uncovered most, if not all, of these failure modes so they could be designed out of the system before they occurred. This lack of rigor is also the root cause of the 737 MAX problems as no half-decent FMECA would have allowed redundancy killing HW/SW designs that are rampant in that design. I avoid flying 737 MAX aircraft for this reason.
Thanks for this very interesting and well explained video. It sounds like the A320 family are the only airliners to show these recurring 90 degree nose gear incidents. Is it the case or have such incidents occurred with other planes ??
There are issues with planes' landing gear all the time. The only thing going on here is that a bunch of completely different failures have resulted in the same eye-catching symptom.
Yeah, gear tempt to work in weird ways sometimes. That’s pretty much universal with any aircraft type and manufacturer. What stands out here is the unusual position that is making this incident „series“ somewhat special
If there's anything I learned from watching this video after the longer video on the main channel, it's that the way you explain the situation in 20-30 minutes on the main channel is a lot more interesting than the condensed 2-3 minutes. Love all your content as always!
The rims are made out of Aluminum or Magnesium, both metals are fairly soft (and spark nicely), additionally only about 10% of an aircraft's weight are actually on the nose gear.
It the runway was equipped with runway centerline lights, I would imagine a lot would need replacement. Even though they are flush with the runway surface, I would expect them to be damaged in that situation. But the concrete gouging would probably be minimal. Asphalt would probably suffer more than a grooved cement-concrete runway.
Hello Peter. Thank you for your videos. I would like to know why there are no exterior cameras on these aircraft (like for example Teslas have) to be able to visually confirm if something is wrong with any part of the plane without wasting time and fuel doing flybys or visual inspections from other aircraft.
Aerodynamics, added weight, added complexity, added cost... all for something so rare you'll be hit by lightning on the ground before the camera is ever useful. And what then? You still gotta land nosegear sideways
Airbus has a lot of automation, and its controls in the flight deck is not physically connected. This probably reduces the feel of the aircraft since the computers are damping a lot of movements.
Having been a plane passenger only once, I find these videos informative - can't decide if I'm more anxious or more reassured after viewing them! Still, flying much safer than driving, for sure.
Great video as always Petter! Question for the room here... is this an issue that has only affected the A320 or have similar issues affected other types?
Seems to me a very SIMPLE thing to do would be add a front landing gear camera. One that looks down at the gear once it is down and locked. This would at least tell the crew what the wheel is doing if they are getting the alarms. Cheap and simple add-on so at least they KNOW. It's not a fix for the issues, but no more fly-bys unless of course the cameras don't work. But, what do I know.....lol Greg
Good idea but NOTHING in aviation mods is “cheap and simple” - although you would think so. To add a camera youd need to screen in the cockpit or modify software to allow camera to feed into a current screen. You’d have to have design testing and certification of the camera location and install. The camera would have to somehow not be blocked by dirt and debris = ground crew function between flights , etc etc etc. - makes some sense but not “cheap or simple”.
It's overall cheaper to simply ask people on the ground to report the condition on a low pass go-around. Compare the expense and resource requires as Marlin mentions to implement, plus the increased maintenance, vs the number of incidents. It's not a good business case to add weight, cost, complexity to this aircraft.
But the pilots aren't even supposed to do a flyby to let ATC visually confirm the orientation of the gear. So it seems like the knowledge of the orientation of the gear is not that important for the pilots to have. Otherwise a flyby would be mandatory whenever one of the faults is shown on the screens.
Small nitpick, but it's caster, not camber, that naturally returns the nosewheel to the centered position. Great video! Love your in-depth coverage of this. Makes you glad to be flying a B737, doesn't it? Haha.
10:05 is it not better/safer to have the wheel locked at 90 degrees than having it at let's say 45 degrees? I mean , I think that at 45 degrees the plane would start steering as soon as it touches the runway and would end up on the grass , while on 90 degrees it think it's much easier for the pilots to keep the plane on the center linie.
Not so sure about that. In both cases the traction of the nose gear is going to be pretty much minimal, practically becoming a broken snowboard. Once the aircraft is touching down, the momentum (in terms of direction) is gonna be set and the aircraft is going to hold this direction till it has stopped. You can see this on intact gears too, once a certain speed it exceeded the tilt of the nose great will have minimal to none effect at all :)
@@dopepopeurban6129 What are you talking about? Anytime the nose gear is on the ground it has traction. The more it deviates from the center the more difficult it gets for the pilots to counter it with the rudder.
@@nurav_7 that’s physical bs. The higher the speed the less traction there is. Have you ever wondered by racing cars slow down before heading into a curve? - Because the cars can’t take the turn if they’re too fast. Their momentum in weight and speed is so high that their wheels aren’t able to turn the car in a normal gradient anymore aka the force of the cars combined speed and weight outmatches the resistance of the wheel - the traction - and thus lead to a loss of agility in steering. With your logic, these cars wouldn’t need to slow down before taking a curve and things like drifting would be impossible. That’s not how physics work.
Very nice video again, thank you :) There is only one thing I do not completely agree with you. And that is about (not) using ground spoilers during abnormal landing gear configuration. In my opinion the reason to not use spoilers is to prevent high pressure on the landing gears during rollout and reduce the risk of a collapse. Passenger evacuation is still possible even with the groundspoilers up. The evacuation route from the overwing exits towards the ground is very close to the fuselage and at that part of the wing, there are no spoilers.
For constructive criticism, your luminance values seem off in their conversion. Specifically the @16:11 range forward, there are no luminance values under 16, and non above 235. This seems to indicate there's an error in 0-255->16-235 (or vise versa) conversion. This is as played in a web browser directly through youtube. Downloaded as an mp4 I can of course control this manually, but if I need to change it more than once per video there's an underlying issue.
The only thing I would like to have seen added to this is why is it just the A320 repeatedly having nose gear issues? How are other Airbus's and Boeing's designed differently that prevents it?
I doubt the A320 is having more nose gear issues than any other plane. If you watch the video closely, you see that there were six completely different failures, and the only reason they're in the same video is that they ended with the same symptom. On other planes, those completely different failures would have had completely different results and nobody would be saying "Aha! Pattern!" Think about engine failures, for example. Sometimes it's because of a bird strike, sometimes it's volcanic dust, sometimes it's fuel starvation, sometimes it's a manufacturing issue with a turbine blade, sometimes it's improper maintenance, sometimes it's the pilots shutting down the wrong engine. It would be wrong to just focus on the common symptom of "the engine stopped working" and start asking "Why do plane engines keep failing?"
@@beeble2003 I think this question is very much directing into this pattern. I mean look at what people say about Boeing, regardless of the problems nature. Sad people just want to point fingers at other people instead of focusing on problems and solutions, the exact reason why any of these peeps aren’t suited for jobs within aviation industry lol
@@beeble2003 According to another post, the 737 mechanically locks the nose gear in place when airborne. When's the last time you heard of the 737 having this issue? (I guess Airbus could borrow this tech from Boeing in exchange for some help with 737 Max stability.)
@@joesterling4299 The last time I heard of a 737 having _which_ issue? The whole point is that these incidents all had different causes. There is not "an issue" -- there are several issues that have all caused the same symptom, so they look like a pattern (including maintenance failures, and pilots ignoring the manual and trying random sh*t to fix the plane). On the 737, an equal number of completely different issues manifest in completely different ways, so people don't see a pattern.
Airbus nose gear centering mechanism is over-engineered. The 737 has simple built in cams which mechanically engage and centers the nose gear as the nose gear becomes airborne.
It seems to me that it's wrongly engineered. The damn thing should get locked straight ahead in flight regardless of anything else. From what you said, I guess this is exactly what Boeing did with the 737.
You have no idea. Airbuses are ludicrously over-engineered and there is at least one computer for everything. Most of my time spent working on the Airbus is spent looking for the right circuit breaker to pull and reset to get the stupid computers working again.
@@StarHorseLover2012 That’s absolutely true, but that’s why the 737 MAX debacle was so shocking; it was a very rare misstep for Boeing engineering, and that decision appeared to be more cost-driven than usual. Usually their designs are very robust and fault tolerant. Historically, Boeing’s weakness has always been they put too much trust in their suppliers. They spec out parts for their airplanes, they probably award the bid on lowest price alone, and sometimes they get absolute junk for parts in return. Remember the 737 Classic rudder hardovers caused by jamming hydraulic servos built by Parker-Hannafin. They probably didn’t expect the Japanese made lithium batteries for the 787 to undergo thermal runaway, nor did they expect the 737 MAX angle-of-attack probes to be failing after mere months in service.
I've been building and repairing computers for 25+ years now and I've run into a number of situations where the standard procedures for a particular issue didn't fix the issue as it was something else causing the issue. You don't know how many times I've had to go against what I was taught because as you said "It may look like the cause is the same but it's not." On my midterm exam on my first year at a VoCal school, I faced an issue where a particular Windows installer file couldn't install this particular file as it kept failing a checksum check. I went thought the normal checklist of trying a different install CD, different CD-ROM drive, drive cable, etc. No matter what I tried that same file kept throwing up a checksum mismatch. The actual cause of the problem was one that neither myself nor my very experienced teacher had ever seen before for this particular issue, a defective RAM stick. My only assumption is that where the memory address that was defective just happened to be where the Windows installer wanted to expand that file into RAM and it somehow always went to that same address when trying to expand that particular file. Weird.
11:26: This is amazingly stupid. By telling me that the pilots ACTUALLY TOOK OFF with this fault, you're telling me that the pilots would have failed to notice the frictional grinding of the nose gear on the runway while at the same time failing to hear the bang from the rupturing tire as the pavement tore into the tire. Also the pilots would have had to fail to notice that the plane was not getting up to takeoff speed as fast as normal because of the friction of the locked nose gear with the runway. So then, you're telling me that with all the problems which a nose gear locked at a 90-degree angle would have caused, it STILL took a warning from the instrument panel for the pilots to know anything about it. That is mind boggling. Somebody in the cockpit had to be blind, deaf, or otherwise not doing their job --- which then raises the question of what kind of passenger wants to fly with pilots who can't even notice a locked nose gear while the plane is moving and taking off.
I mean, I'm pretty sure those engines put out enough thrust that they wouldn't really notice something like grinding down a wheel all that much. That's like expecting a gamer to notice the difference between 59 and 60 fps on a gsync display. I bet even air conditions make a bigger difference to engine performance than wasting a few lbs of thrust grinding a wheel down. Metal isn't exactly a 'grippy' material. If you've ever driven on rims or ground metal on a grinder, you'd know it's like ice skating compared to rubber tires. The noise though... No idea. Maybe the cockpit is isolated enough it was barely any more noise over the engines. Maybe the tire rolled off the rim cleanly enough that there wasn't a sudden drop of the nose, either.
@@MyNathanking I just wish we could get some extra data on it. I tried looking up coeficients of friction, but metal on asphalt is around 0.7, which... is almost what rubber was listed at?? Must've been static friction, but being anywhere near rubber still seems pretty high to me.
The wheel was probably not at 90 degrees during takeoff but the faults that caused the wheel problem were there. Wheels don’t just turn at 90 degrees at takeoff, pretty sure the pilots had to taxi to the runway right?
So do any other aircraft suffer similar n/w problems (as often) or are Airbus just particularly bad at n/w design? Even if the causes are different in each incident it just shows how many failure modes are in the original /redesigned system. How many others are there yet to be uncovered?
Can you explain what would happen if the plane needed a Go Around after the people have been moved to the back? On the Airbus website it says "In case of go-around, setting TOGA power induces a significant pitch-up moment that needs to be compensated for. The more aft the CG, the bigger the pitch-up moment. If the CG is too far aft, and outside the envelope, the pitch-up moment induced by initiating the go-around may be too big to be compensated for. At low speed, high angle of attack and TOGA power, the pitch-up moment increase due to having a CG position too far aft, may also trigger the alpha floor protection, thus prevent its sufficient compensation." Moving people to the back and reducing the landing speed sounds like it could come to a catastrophe if something else went wrong on approach and GA needs to be executed.
Wait what? They took off with the nose gear at 90°? That would have already half destroyed the nose gear even before they came in for an emergency landing. That landing must have been extra sketchy and dangerous, right?
I just thought of another reason to shut down the engines on landing if the nose gear is cocked sideways at 90 degrees. It doesn't take a collapse to send debris back towards the engines. That spark trail is made by debris coming off of the landing gear. Admittedly almost all the debris is very fine and won't do much damage. But there are going to be a few larger chunks that may come off as well. Including as likely candidates half lug studs, half lug nuts, half the axle, ball bearings, half of each rim and tire chunks. My reasoning is that once slightly more than half of a bolt and nut are ground away there is little holding it in place. This makes it much more likely to come off and bounce into that trail of sparks. I have done automobile maintenance but no aircraft maintenance. So a few things to note that almost any mechanic with experience will know. I am assuming that aircraft wheels are similar to automobile wheels (with more exotic materials on a larger scale). On a car the wheels are held on by a set of 2 part fasteners. There is a hole drilled and tapped into the hub. Into this hole is inserted a threaded stud. One end of the stud sticks out from the stud. The rim is placed over these studs so that they show through holes in the rim. These then have lug nuts tightened onto them. (Yes, I have replaced broken studs. It's a pain in the ass). The second is that sometimes the only way to get a REALLY stubborn but off is to use a nut splitter. A nut splitter uses a wedge driven by a bolt to crack a nut in half. Once split in half, the 2 halves will usually just fall off.
Great video, My career is as an Aircraft Technician. Sometimes all of these new designs and new issues make me wonder. The old designs worked for many years with minimum issues. If its not broke don't fix it. I enjoyed video fully. Keep them coming ❤️✈️ 🌎
Yeah I totally understand that. Less weight less fuel burning more passages and cargo more profits. Some times they just go way overboard. That also happens on internal parts of some Turbine engines too.
I have done very little work on the A320 series, I would guess that it does not have a centering cam built into the strut since the BSCU moves it around before landing. Most, if not all aircraft I've worked on have a physical cam built into the nose strut that it will fall into when the strut is fully extended after take off. Is this a design that some of the other newer Airbus's have?
14:51 "A lot of sparks coming off the nose wheel, which would be normal" When such an incident is so common that it gets referred to as normal... Maybe they could simply replace the whole nose gear with a wooden pole - cheaper to replace, less wear on the runway and possibly less potential for causing engine damage.
It is good that investigations are carried out on all incidents and not relying on "we have seen this before, it must be XXXX". As you have showed in the nose wheel issue, the casual factors were all different. Alarms and warnings don't tell you why something happened, and in most cases what is wrong, what they tell tell you is that there is an issue with a component or there is an issue with the circuit (hydraulic, electric or cable controlled) and possibly the component. While I 100% agree that following the relevant check lists, and agree this is the first thing to do, there have been many instances where Pilots have had to do their "own" thing, some if not all having been shown on your channel and others. IE the QANTAS QF32, Olympic Airways Flt 411, Air Canada Flt 143 (side slip like a glider) incidents and the list goes on. I know there is a greater risk when operating outside the published processes, however as long as they follow the process first (or attempt to), then sometimes the Pilots must use their experience, their experiences of the particular aircraft with it's own performance characteristics they are operating, knowledge of flight principles and whatever else is available to them to safely bring the aircraft down. I have no doubt that at the height of an incident, especially the three extreme examples I gave,, the cockpit can be a tense place, that's where we (the passengers) rely on the flight crews professionalism and ability to communicate to each other, because that is the greatest tool they have - each other in dealing with the issues at hand.
Ok... But even though all incidents were caused by some or totally different reasons, in the end what I'm seeing is a huge problem with the design of the entire front nose gear system that allows for many points of failure. Airbus should address it with a more radical solution than a few software tweaks and minor hardware adjustments and maintenance procedure instructions
The trouble with radical redesigns is that they're not only very expensive to do, but also that it's very difficult to validate that your design is safer, better, and more reliable than the previous one. I work in the world of software, and radical redesigns of code are pretty rare in the enterprise world even though it's much cheaper to do this in software than hardware. This is mainly because it's difficult to justify changing critical components in a radical fashion unless you not only have a strong justification for it, but also sufficient metrics and testing around it to ensure you don't actually see regressions in the functionality and performance of that component. Design is hard, and regressions are actually very common when even doing minor refactors. I can only imagine this is even more true in the world of hardware. We might have over 300 tests for a single component, and in software those tests are cheap to run. In hardware land, physical tests are very expensive and may even be infeasible for certain scenarios. I'm sure they did a lot of simulator testing too, but you never will know how exactly it'll perform until it's in the real world being used. There's a reason why the phrase "better the devil you know" is often used. A radical redesign might sound good on paper, but in fact could introduce a whole new class of failures that now no one expects to see. Confusion between maintaining the different types of landing gears could introduce weird issues that the manufacturer never expected. Even if the design as-is clearly has some faults, the relative rarity of those faults still means that it's a functional design that is safe for flight. It's not worth the massive risk to throw all that away for something completely new.
@@MNGoldenEagle yes, but it's also important not to go too far in the other direction. An extreme example was the Therac-25 radiotherapy machine, which killed six patients while the manufacturer and technicians tried one little thing after another to paper over a fundamentally dangerous design. Even in lower stakes situations, a poor initial design can lead to extremely expensive technical debt; a full rewrite may be the best and cheapest option.
@@MNGoldenEagle but we are talking about aviation. It's famous for being all about safety and this whole issue seems all but safe. The design has to have critical flaws if so much stuff can lead to the same failure. Fortunately, any of the incidents have turned into fatal accidents so far, but we've seen previous events in which a failure in the landing gear can lead to debri punching into the aircraft's fuselage and leading to much more severe damage and even fatalities.
Does this happen with any other planes at nearly this frequency or is there something about the design of this nose gear and its sensors that makes it basically default to 90 degrees off center when something goes wrong?
Wow, this is actually really funny. Like, yes, there is potentially a lot of stress for the pilots and passengers involved but there's also something funny about this recurring failure. I can just imagine Airbus engineers sitting their going, "Oh, here we go, it's the nose wheel steering again!"
Nose wheel steering uses opposing hydraulics. Loss of hydraulic pressure on one side has the same effect as actuating pressure on the alternate side. Either pump or it’s electrical connection can cause the nose wheel to do that.
I enjoy air crash investigations. They are very thorough and I always feel satisfied after going through Mentour Pilot's explanations. But not this one. I understand the cause were different for each case. But there are serious questions still unanswered. Why only A320? Why the nose gear aren't resistant to water? Does that mean it is unsafe to lower the nose gear in the rain? Why they are not grounded? Does someone have to die first before a more drastic action is taken? Is this a clue that there is a bigger organizational problem hidden within the Airbus?
Unfortunately Mentour's click-baity headline has encouraged the packs of keyboard warriors and seat-flying experts to see scattered incidents as an epidemic. "Why only the A320"? It isn't "only" the A320. Pick your plane, you could do the same for any common type. A quick Google tells me that the 737 Classic (2000 produced) had 23 main gear failures in 17 years. "Why they are not grounded? Does someone have to die first before a more drastic action is taken?" etc and so on ad infinitum.
@@MentourNow I will ask you then who was quick to judge when my comment "Why am I not surprised a computer created a problem where there was none? I wonder how many of these airplanes will still be flying in 20 years." was censored?
Reminds me of a structural engineer I knew who was tasked to design a structural support in a large jet’s wing. Another engineer was tasked with designing the next support over in the wing, a third engineer did the next support, etc. None of the engineers shared how they were designing their respective support. That project didn’t even involve a computer controller, which complicates safe design. Why the company chose to silo the component designs is beyond me.
Those instructions in the "extra section" towards the end of your description of the check lists, just before showing the latest video, were exactly what the pilots did in your big story about the Jet Blue incident on the other channel. Move passengers back, "brace", etc., etc., etc. It underlines just how brilliantly that crew acted - they didn't just go "by the book", they effectively wrote it! Even though each problem you described was different, it does seem to me - a total layman when it comes to engineering! - that the whole nose wheel array (internally and externally, hardware and software) should be redesigned. There _shouldn't_ be so many possible faults, at least that's how it seems to me. Had one of the earliest incidents ended tragically, I do wonder if the authorities would demand a redesign, especially if there had already been a few, benign, occurrences. I'm obviously relieved that no one has been hurt by the recurring outcomes of so many incidents, but that does leave me wondering if the problems are being taken seriously enough. What if a landing needs to take place on a wet runway? The "let it roll to a stop" method could well end up with a plane running off the runway and onto potentially hazardous terrain. I dread to think of the outcome should that happen. Fascinating as ever, Petter. Thank you so much for your excellent work.
So this happens with some infrequency. When it does happen, is the runway repair bill automatically charged to Airbus if it’s not a maintenance infraction?
Cuz of certification, lighting, checklist procedures, pilot training, implementation, regulation and development cost. It’s far more complicated than just taping a GoPro into the gear bay and sticking a monitor to the other end of the cable.
@@mateuszzimon8216 yea but I don’t see the benefit there. One way or another the pilots will know that something happened to the nose gear and a 90* rotation rly isn’t the end of the world. The gear is gonna be broken for sure after landing but the aircraft will come down safely.
It's these new-fangled systems that are causing these problems. Consider that the ever-popular DC-3 has NEVER had a nosewheel steering problem in the 85 years it has been flying. Maybe those old guys weren't so dumb.
I understand each incident was caused by differing faults and or failures. However in my opinion the front nose gears overall design is not the best example of aircraft mechanical engineering. I don't believe because each incidents causes are somewhat different they should be written off as coincidences. Airbus should consider a more thorough engineering review of the complete system as a whole. Thanks for bringing us the story's and as always well done.
In 2000, i worked in a tall office building beside LAX and we went outside to witness the aircraft landing with its nosegear at 90deg. Unfortunately i cant find the plane type as your video made me wonder if it was the same as the more recnnt aircraft. I was wondering why they couldnt turn on the APU rather than rely on a ramjet which itself might impact the rumway? Thats what i would do if i were pilot. Shut it off after coming to a stop on the runway before evacuation (or during because its intake wouldnt risk any passengers). Another thing i firmly believe is that every control shpuld hace feedback. If rhe Captai s steering hamdle were at 90deg it would be an easy indicator what the wheel is doing. Without feedback you cant even walk. You wouldnt know if your foot was on the floor or bumped into a wall as you continued the motions. Feedback is essential which is why they call it AI.
As an engineer (not in the aviation industry), I want to add that it's true that a fault that appears to be same might have have different causes, BUT if the same part keeps having problems and you are fixing it time and time again and always something new pops up, then you sometimes want to scrap that part entirely and design it from scratch again - ideally, using a different engineer. Oftentimes 80% of the problems are located in 20% of the parts and if you already found that you have a part at hand which keeps suffering all sorts of problems, there might be more to discover in this part. And then it might be cheaper and safer to scrap it and start designing this part from scratch again.
This is what an effective Failure Reporting and Corrective Action System (FRACAS) is supposed to do. Find the root cause of the failure, determine a corrective action to fix the root cause, and then, in a step that is rarely correctly implemented, evaluate the effectiveness of the fix. After the second incident at the latest Airbus should have performed an extensive FMECA leading to failure mitigation redesign if the NLG and SW systems.
of not if😂
Agreed, 90% of the time we even know the system was badly designed, but it is too expensive to redesign something in production so in go the workarounds.
On the other hand the A320 is one most-built passenger planes and seeing use in the EU it might even do more starts and landings than the 737, which will increase the number of incidents. But yes, getting fresh brains on this, maybe not to redesign but to test its limits in creative ways, would help, but on the other hand: The A320 not even lands with a 90 degree wheel but will even start with one.
Lol. There are so many problems with the landing gear. Let's get rid of the landing gear!
Maybe they should just land sideways.
😂😂
HHSHADHAHSHHDHASH
Drifting Simulator: Airbus
That's called crabing and passengers love the view on the low wing side.
B-52 mode?
I think the most important take away from all of these incidents is that the nose gear has not collapsed after landing 90 degrees to the side like this. I don't know how close to collapse they've been, but they haven't collapsed. That speaks volumes to just how incredibly strong those struts are.
It seems like 90 degrees is a default position by design. Any other position between 0 and 90
would cause the plane to veer off the runway which could be a potentially dangerous situation.
That might be correct
Interesting point, I'm going to guess keeping the landing gear steady at 0 degrees will be much harder to do. It is curious that in these incidents, it didn't collapse. I found this part especially impressive. My uneducated guess would have been the forces would have been great enough to rip the landing gear right off.
that would be smart engineering, not standard at less important engineering jobs... or luck in this case
I've heard a couple of A320 pilots mention that it is indeed a "default" position for exactly the reason you mention.
@@notsam498 Landing gear is one of the strongest and toughest parts of a commercial aircraft, second only to turbine blades. Tyres and even wheels wear surprisingly easily compared to the strength of the gear and its mountings. If gea R gets ripped off, you know it was a oarticularly hard impact.
I remember JetBlue 292. I watched it live, and also remember passenger interviews stating, "It was one of the smoothest landings I ever experienced." This just puts on display the pilots' skill level with events like this over the years...
Hopefully they have a 'Nose Gear Out Of Whack Checklist' now.
I would be interested to know how the design of this nose wheel system differs from similar planes, as well as some design engineer's comments regarding the A320's design. So many problems with a single system leads to obvious questions.
Me too . From a software engineering perspective this sounds like a design or implementation quality problem, especially in terms of the BCU
I agree. It does seem like an absurd number of incidents with the same resulting issue, regardless of the cause being different. It really does seem like some kind of design issue.
Airbus should call Boeing and ask "how much to license your nose wheel design and software?"
I almost wonder why they haven't installed a sideways skid or roller to stop excessive wear down
Keep in mind, we’re focusing on a narrow subset of the total set of problems these aircraft experience. This cannot be the only component on the aircraft to fail.
That said, how serious are these nose gear failures?
How many lives lost?
How many airframes destroyed?
How many people crippled or seriously injured?
How much total $ in losses - destroyed equipment, maintenance time, lost flying time, etc?
Keep in mind, I can point to video of an aircraft, at the gate, engines off, exploding because someone failed to replace a washer during maintenance (No, not nose gear - if memory serves, it was part of the slats extension mechanism).
With the vast array of parts, systems, etc, on aircraft, designers need to pick & choose which failure modes to design out, which are unpleasant, but still the lesser of evils, and which are not worth their time (because there are bigger problems to tackle).
I realize how seriously this could have gone wrong, but there's something inherently funny about Airbus going on a Wile E Coyote like chase after the nosewheel that keeps going wrong in increasingly unlikely ways.
+++
"okay we have made it completely impossible for the nose gear to rotate 90 degrees before landing"
"sir I've just received a report that a nose gear has rotated 90 degrees before takeoff"
@@danielderias4773 "GODDAMNMIT!!"
For me it's the fact that by the 3rd time, the pilots's reaction was essentially:
"We're getting warnings about steering aren't we?"
"Yup"
"The nose wheel has turned 90 degrees hasn't it."
"Most likely"
"We're going to have a pain landing aren't we."
"Definitely."
shit received more fixes than mcas💀
Fascinating. I can imagine the engineers at airbus starting to get really frustrated. “Again, John? How many times do I have to fix this?”
More like Jacques
Have you ever heard of Boeing?
Sounds quite crazy that you could dispatch with any fault in nose gear. I would not like to be inside such plane. Luckily it seems to be amazingly tough thing. Once in Helsinki-Vantaa a van got knotted around main gear with no problem.
Agreed!
lol. right. that's irresponsible
It took off so don’t worry.
@@Tangobaldy it took off in an unsafe position, that should never have happened in the first place
@@FL0RiaN94 I think that they didn't notice the nose gear during takeoff, because of the momentum of the plane possibly forcing the wheels into the correct position, but once the pressure was off the wheels, they popped into the 90° angle that they wanted so badly.
Pilots maybe thought some unexpected sidewind or whatever, instead of a stubborn nose?
I love these videos and they are always very professionally presented. Just one little point - the editing is so good that it sounds like Peter never stops to take a breath. Sometimes a few seconds pause as happens in normal conversation or even a lecture, allows the listener to take in and process what has just been said. Just a thought! :-)
Yes, we have noticed that. Thank you
excellent point Robin excellent point.
I put Petter on .75 % speed so I can hear and absorb everything he is saying. It’s like he’s in competition with time😉
😯Its just a notmal pace to me
I would blame You Tube as they always want videos cut down to the shortest possible time it seems. So it might be a case of having to talk quicker so everything can be included in the video?
"how they didn't notice that, I'm not sure," sounds like a very polite way to say something significantly less polite. I'm actually laughing at that that sounds.
Your explanations are still awesome to enthusiasts like me. Glad to see you're still absolutely fantastic!
That's what I call polite but not nice.
maybe theirs a lock on the wheel that locks it into position, that broke and given the direction of the aircraft and how it was moving, allowed the wheel to rotate forward in the general direction of the aircraft's movement and allowed them to proceed with the takeoff normally until they got it in the air and put it down and the force of the resistance of the air on the wheel jammed it in the most inaeordynamic way
Ah, yes, the polite way of saying 'use your eyes, mf!'
That’s insane they didn’t notice. They are almost sitting on top of it, that had to make one hell of a noise.
Capt on A320, now retired, 1200 hours command, on type, my experience of nose wheel problems, was as follows.
Half way thro a take takeoff, nose wheel commanded 45 degrees left.full right rudder applied, To get back near the runway centreline. T/O continued.
Inquiry stated unknown fault of BSCU.
Previously, the company had a similar fault, crew rejected the T/O and the aircraft had a runway excursion. BSCU issue, again.
The different modes of failure leading to the same result reminds me of HVAC service calls I've been on. "My air isn't cooling 'again'". Then I get there to find a totally different failed component than the time before. But trying to get some rental property tenants to understand that can be challenging.
You get this situation in any technical field. I used to do TV repair. Any one of a hundred parts could cause loss of sound. As far as the customer is concerned its the same fault every time. What you do is build in a bit extra in your standard pricing, so that when luck brings you back to the same customer with the same symptom(s), you can fix it for free and retain the good will. You cannot expect customers to understand technical detail.
When you fix faults you should also do basic checks that usually will reduce the probability of a callback. My car was leaking coolant, so I took it to the dealer. The mechanics spotted that a hose was weak so they replaced it. But next day it still leaked coolant. This time they identified another dodgy hose. They considered that a separate fault and wanted to charge me full parts and labour again. My view was that if they were competent, once they found one dodgy hose, they should have checked ALL hoses - after all they were all equally old. So I offered to pay for the extra part cost but not the extra labour, as the labour in the first job I had already paid for turned out to be not properly done. I had to fight for that one though. But if it was coolant leak problem and next day a brake fault, then clearly the faults are unrelated and the customer should pay for two different lots of parts and labour in full.
What kind of repairs have to be done to the runways after these types of landings? I imagine that they cause a fair amount of damage to the surfaces of the runway. Great video by the way.
How does the nose-gear on the A320 differ from those on other Airbus aircraft that don't seem to have the issue?
I'm actually impressed you can grind off half a nose wheel while having the weight of a jet aircraft pressing down on it without any visible damage to the runway. Amazing material!
The nosewheel supports less than half the weight of the aircraft (maybe around 25%?). Still it's significant weight. But the fact that the wheel ground away so much says how much harder the concrete is compared to the aluminum of the wheel.
this would be simulated & tested in case something like this happened - so yeah, intentionally designed to not collapse if tires blow up
@@rnreajr9184 Another commenter said it was a maximum of 4 tons of pressure on the nosewheel (out of 65 tons, overall weight). I don't know how accurate he was being, but if that's the case, it's a lot less than 25% of the weight. This wouldn't surprise me, based on the some photos I've seen of large commercial aircraft tipping and falling onto their tails with improperly loaded cargo or even because of the horizontal stabilizer being blanketed with volcanic ash (which happened to a lot of parked aircraft during the Mt Pinatubo eruption in the Philippines).
@@skyhawk_4526 Yeah I saw the comment. He claimed the nose gear takes about 10% of the landing weight. Still very impressed that with multiple similar incidents, the nose gear holds up. Scary stuff, but an amazing testament to the integrity of a moving structural part.
@@skyhawk_4526 That wasn't 4t of weight on the nose wheel: it was a 4t friction force due to friction between the nose gear and runway. (The weight is a downward force; the friction is backwards.)
I wonder if Airbus has done any major redesign of these systems for the Neo since it kinda seems "too easy" for the landing gear getting stuck like that for a variety of reasons
Yes.
apparently, mitigations have been implemented even in newer CEOs The LATAM plane, CC-BAS is 10 Years old,delivered to LAN Chile on November 2011
Yes, the company designing and manufacturing the nose landing gear changed its name from Messier-Bugatti-Dowty to Safran Landing Systems. That should do the job. Right?
While there are differences, there is still a theme somewhat, in part including bad maintenance. Hopefully they've worked out the rest of the bugs. The main outlier would seem to be power washing. Instead of reemphasizing "don't do that!", it seems to me to be better to redesign to withstand it if possible.
I remember when it seem like a rash of Boeing 727 (yes, I'm that old!) had issues with their nose gear Not Extending when they came in for landing! I think that there might have also been a few cases with the nose gear extending but not locking in the down position...
I Do remember when one pilot was able to trim his airplane to such an extent that he was able to keep the nose of the jet off the ground until he was going (what seemed to be) about 6mph (10kph) and the nose came down reasonably slow!
i'm astounded by how the struts don't get torn apart during these landings, despite the faults, that's some amazing structural engineering
Indeed!
I am not surprised by this as I spent over 40 years working for a major Avionics manufacturer. A fault would be flagged and something totally unrelated would be causing fault and not fault that was flagged.
Sometimes the computer in my car will display several fault codes at once. Repair shops like to estimate the cost of repair based on EVERY fault code, and add them all up for the grand total. I bought a factory service manual and studied the relationships between different systems and can pretty much zero in on the problem. I think some of these automotive systems are overly complex, so I can only imagine how complicated aircraft systems must be.
@@RetNemmoc555 Interesting I did exactly the same thing with my MR2 Spyder. The factory repair manuals for this car are 4 inches stack! I just can't imagine the work load on a commercial airliner when things go South.
@@RetNemmoc555 Yes aircraft systems are much more complicated than automobile systems. But the basics are still the same and there is an interrelationship between systems no matter where they are used and sometimes its not that easy to diagnose what the problem is! Yes they are putting in systems that are way to complex for there own good. they need to use the KISS principle. Keep it Simple Stupid!
If you want to see the most reliable, concerned for the customer, knowledgeable auto mechanic, you ought to check out TH-cam videos from Rainman Ray who lives and works in Florida. He often not only explains why auto systems are so complex, but how complete a professional code scanning system can examine and manipulate virtually all the systems in modern automobiles.
@@RetNemmoc555 My sister's KIA Soul has the EPS warning lamp on. The problem with that is the car basically using it as a master caution warning.
I can understand that all these are different failures, hovewer it is obvious to me that there should be design review and some is still wrong here. Typically some mechanical locks are used to block gear in default position in case of controls failure. This should be implemented here.
I'm pretty sure that the 320 rotates the landing gear to the 90 degree mark before stowing. That said, if there is a failure then the nose gear is already locked at 90 so as to prevent a more serious landing problem of a misaligned front wheel such as in the case where the locking pins were sheared off.
The majority of these faults would not be fixed by a lockout as the computer would have unlocked the gear before a fault is triggered.
Then there is a problem of a lock adding another point of failure vs how many failure points are present.
Every other airplane on Earth with a nosewheel oleo strut has what you’re talking about: a nosewheel centering cam. It works off the extension and compression of the strut. When the airplane is in flight, there is no weight on the gear, so the strut is fully extended, which engages the cam and straightens the wheels. When the airplane lands, weight on the strut forces it to compress and disengages the cam, allowing the nose strut to rotate for steering. How and why Airbus designed their steering without a simple, mechanical, industry standard safety mechanism and managed to get it certified is beyond my understanding.
@@Tony-Waldron I thought so as well, at least I thought I had seen that and assumed it would need a less deep wheel well, but that must have been a differnt type of aircraft. I looked it up and in a video where they executed a gear retraction test during maintenance with the aircraft jacked up, it went up with the wheels straight. Also there seems to be a braking plate on the top of the well, to stop the tires from turning after retracting the gear.
Two thoughts -- 1) I'm constantly impressed by the ability to identify how such failures occur; 2) if the nws has so many different ways to fail, maybe a complete redesign is in order?
My thoughts too
Very good presentation. Just one comment: The A320 doesn't have a Standby BSCU. The BSCU is a dual channel unit and channels are swapped by cycling the AS/NWS Switch. Late model A320s have an Alternate Brake Control Unit (ABCU) that is not associated with nose wheel steering.
According to Airbus's Safety first report titled "Landing with Nosewheels at 90 degrees" , this is what is written for the 2007 NWS 90 degree incident
"An updated design was introduced to improve the robustness of the BSCU and to allow a switch-over to the passive BSCU system when the outputs of the active BSCU system become frozen (i.e. switch from BSCU 1 to BSCU 2 or vice versa)."
You can search for the document on Google. or on Airbus Safety first website.
@@swapnilmankame JetBlue's N536JB was pre-modification that introduced the ABCU.
One of the MANY reasons I watch your interesting videos is the incfedible similarity between modern airplanes and IT systems (meaning endpoints, servers, network, storage, you name it). I work as system administrator in one of the most complex possible environment (a network of cruise ships)
Both are a sum of many very complex systems and very often improvising or going with "post hoc ergo propter hoc" is the first step to failure.
Many users tend to simplify the problems because they don't have the "big picure" of the situation, is human and it happens with computers as well as with airplanes.
Keep doing this videos Petter, they teach more than you can imagine to us IT flight enthusiasts, thank you!
Firstly I imagine and Airbus 320 pilots must get this event included in their simulator training. If not it should be.
Secondly are their any other systems that are this problematic in both number and variety of causes? on any other common airframe?
Finally, has this become a some sort of fatalistic joke in airbus pilot circles?
It is in training and in the QRH and it is also a joke XD
If there are similar failures occurring in other systems on other types and makes of aircraft, we'd be the last to know. Such things are only made public when there's no way to hide them.
@@EleanorPeterson You don't understand the industry very well. When things go wrong with planes it's impossible to hide them. Much too many people involved
@@Stettafire you don't understand aircraft very well. When things go wrong with a plane and you are inside of it, it is very unlikely you would ever find out that there actually was something wrong, because of how much redundancy there is and how large the safety margins are.
@@EleanorPeterson All significant failures and occurrences leading to actual or potential damage or injury are reported publicly, in any civilised country. The UK's, for example, are here www.gov.uk/government/collections/air-accident-monthly-bulletins
Terrific presentation. Like the toughest diagnosis in medicine, it is clear modern systems can’t always be fixed by a software patch.
Especially software that was first written in 1983.
Yet another wonderful and informative video with straight talking explanations for the different reasons that this keeps happening yet for different reasons, you really do give better information than anyone I can think of, you really should have your own television programme where you explain all of these questions to the public at large. Flying is an everyday event for many people, yet we know so little about it, it's taken for granted, there have been others before you but in different fields of expertise who explain in detail how and why certain things just are, you are another one of these people, you have a fantastic gift and you deserve more than being on TH-cam.
Take care and stay safe :)
I understand your sentiments about Mentour Pilot being on television. However, being on TH-cam is better than traditional television. If these programs were on traditional television, many would not be able to watch the shows because they would not have the particular channel in their cable TV subscription package. In addition, there would be issues with location, as the channel would only be available in select countries. Furthermore, many people have cancelled their traditional television service, so they would not be able to watch.
With TH-cam, generally people anywhere in the world can watch Mentour Pilot at any time they want. TH-cam offers translation via closed-captioning, so even non-English speakers can still learn from the programs. In addition, TH-cam videos can be viewed by many different devices, such as computers, smartphones, tablets, Roku boxes, Apple TVs, and even smart televisions. That is, you can watch TH-cam videos on a television.
Plus, TH-cam promotes two-way communication via the comments, while traditional television is only one-way communication.
Mentour Pilot going to television would be a downgrade, sort of like going from piloting a Boeing 737 to a single-engine Cessna.
I'm curious, is the RAT automatic? I imagine they would start the APU to keep power and control after the engines are shut down?
The RAT automatically deploys with the loss of AC Bus 1 and AC Bus 2. As mentioned above, if the APU is started then everything is powered and you don't get the RAT automatically.
Somewhere in Airbus someone is rolling their eyes and going "okay how else did the nosegear guys manage to mess up" :-)! Seriously it seems that there are lots of things that happen to have an outcome of the nosegear being rotated 90 degrees left. Still it's surprising to have this many problems compared with everything else - I suppose the nosegear does take quite a pummeling every landing. It does sound like Airbus need to put a checklist into place for landing with nosegear at 90 degrees and all green indications it they're not going to allow the landing gear unsafe checklist (or just say you can use it - which would seem to be the most sensible).
well TBF some of these are related to the design fault, while some are related to maintenance procedure fault. as for maintenance procedure its result of airlines outsourcing maintenance to save costs and idiots getting the job to maintain multimilion dollar airliners.
@@kopazwashere yes, actually my comment was somewhat tongue in cheek :-)! Actually I think these events show how well the nosegear was designed - probably to deliberately fail to a 90degree rotation which despite damage to the wheels/tyres enables a straight landing to be made.
Hey bob why does it sound like yosemite sam in in the engineering booth today, oh didnt you hear? lol
Seems to be a fundamental problem with the design of the gear itself, do we see similar problems happening for random reasons on other models of aircraft?
That was what I was thinking too. On the other hand, maybe you should look at the number of incidents vs the number of flights that passed without incident. In principle, every incident is one too many, but maybe the number of incidents is statistically not very significant. But I got the same idea basically. If there are so many incidents, there might be a fundamental design flaw in the system.
I was thinking the same thing. With a track record this poor, this nose gear should be redesigned and replaced.
@@maybehuman4 There is one thing to hold for them, so far it seems none of the nose gears collapsed, so that thing seems to be quite sturdy at least.
Maybe? I mean 2 of them was literally incorrect servicing lol and 1 was people filling the sensors with water lol
@@0Synergy Yeah, sure, but that doesn't mean it can't be a design flaw. If the design allows for such mistakes, it's the design, not the people making the mistakes. You should design stuff with crucial functions in a way thay can't be mounted incorrectly. And if water is no good for the device, take measure water can't penetrate. Obviously, if you want to sabotage somthing, you can always find a way to mess things up. But it shouldn't be made too easy. I don't know all the inns and outs of this system, but the fact that there's a video about these accidents, incidents and near accidents, means that there is something going on. There are no videos about Boeings nose gear failures... So, unless Mentour is making sensation, there IS something about this gear.
I'm amazed that there have been so many incidents with the nose gear of this plane. Would it be practical to redesign the whole nose gear from scratch?
No because then airlines would have to scrap all their a320s or add the new landing gear
@@hansloyalitat9774 A wheel on my car went kaput. Should I scrap my car, or fix the wheel? Hmm . . . decisions, decisions.
@@hansloyalitat9774 component modifications & upgrades on airliners happen a lot more than you think. The timeframe for having to make a change could be anything from “next overhaul/heavy check” to “don’t fly until it’s changed” it all depends on how important the component is and how bad the fault is.
It’s for this reason that a lot of major components like landing gear and engines are leased from a 3rd party.
@@hansloyalitat9774 The reason they have not redesigned the whole nose gear is because no one has died YET. Airbus is going through a grace period right now. However, if people die, then the cost will be quite high because they will have to ground all A320's until they are safe to land, will have to compensate the families of the dead, do a costly investigation, and then do a major redesign and costly retrofit. Airbus would be smart to do a complete redesign now, but we all know that won't happen, meanwhile they will just keep doing band-aid repairs and betting against the unthinkable.
@@quietwoodworking This is not Boeing, Airbus actually cares
Does the 737 also test the wheels like that? And did anything like this happen on the comparable 737's?
As far as Ik the 737 doesn’t perform this autotest. However the steering mechanism on the 737 (at least since the NG as the gear went through a redesign during development) has a different locking system, though I could be wrong there. And to be fair I don’t know if any 737 had this gear rotation 🤷♂️
The 737 is still using cable controlled, hydraulically actuated system and got plenty of mechanical stops, even for the MAX. direct control from the captain side. no such test.
Yep. The 737 nosewheel steering is cable controlled and hydraulically powered. There is very little to go wrong with that system.
I am a Reliability Engineer working in this type of air vehicle development. When you design such complex hardware/software systems it is crucial to perform a comprehensive Failure Modes, Effects, and Criticality Analysis (FMECA) in concert with the mandatory Safety Critical Thread Analysis (SCFTA). In the past these analyses were led by the Reliability Engineer who was performing the FMECA with the Safety Engineering function developing the SCFTA with Software Engineering support. As the US has dropped mandating the use of Military Standards in many areas (a result of Acquisition Reform in the 1990s) the level of rigor (yes I am American so US English used here) of these analyses has been left up to the manufacturer for the most part. One result of letting the bean counters determine resources while also removing mandatory processes which require collaboration is that many companies have decreased the rigor of their Reliability analyses including the FMECA coverage and depth while somewhat stovepiping the SCFTA analysis efforts into the Software development process with System Safety supporting Software Engineering.
It is clear that this structure is almost certainly in place at Airbus given the various failure modes discussed in the video that resulted in the NLG being rotated 90 degrees. Identifying, analyzing, and mitigating these failure modes is the MAIN reason for the FMECA. An investment in real FMECA analysis coordinated with the SCFTA activities would have uncovered most, if not all, of these failure modes so they could be designed out of the system before they occurred. This lack of rigor is also the root cause of the 737 MAX problems as no half-decent FMECA would have allowed redundancy killing HW/SW designs that are rampant in that design. I avoid flying 737 MAX aircraft for this reason.
Amazing, interesting, breakdown of the various incidents. Very educational. I wish I could give more than one thumbs up.
Thanks for this very interesting and well explained video.
It sounds like the A320 family are the only airliners to show these recurring 90 degree nose gear incidents. Is it the case or have such incidents occurred with other planes ??
Are there similar incidents with B737 nose wheel for example, or any other commercial aircraft?
There are issues with planes' landing gear all the time. The only thing going on here is that a bunch of completely different failures have resulted in the same eye-catching symptom.
Yeah, gear tempt to work in weird ways sometimes. That’s pretty much universal with any aircraft type and manufacturer. What stands out here is the unusual position that is making this incident „series“ somewhat special
If there's anything I learned from watching this video after the longer video on the main channel, it's that the way you explain the situation in 20-30 minutes on the main channel is a lot more interesting than the condensed 2-3 minutes. Love all your content as always!
What would that do to a runway? Would it require repair to the runway, or is it designed to take that kind if metal scrubbing?
I wondered the same thing. On the pictures it looks like there isn't as much as a scratch to the runway. Which is pretty incredible honestly!
The rims are made out of Aluminum or Magnesium, both metals are fairly soft (and spark nicely), additionally only about 10% of an aircraft's weight are actually on the nose gear.
It the runway was equipped with runway centerline lights, I would imagine a lot would need replacement. Even though they are flush with the runway surface, I would expect them to be damaged in that situation. But the concrete gouging would probably be minimal. Asphalt would probably suffer more than a grooved cement-concrete runway.
@@skyhawk_4526 Only if the plane is going _exactly_ down the centreline.
Aluminum doesn't make any sparks.
you mentioned this on the last mentour pilot video glad it is finally out :)
Man, that nose gear is cursed! It's good to know that all these incidents ended in safe landings.
Im not sure if the A320 Neo is now upgraded on the Nose Gear too.
I can't really believe how such a quality content is just free for all to watch
Hello Peter. Thank you for your videos. I would like to know why there are no exterior cameras on these aircraft (like for example Teslas have) to be able to visually confirm if something is wrong with any part of the plane without wasting time and fuel doing flybys or visual inspections from other aircraft.
Cost, weight, maintenance, and workload, vs the number of incidents. Everything is a trade off.
@@ChristopherBurtraw Also we tried and let people watch this on PMC. Irc A380 have a tail cam but for PMC and don't work on ground
Aerodynamics, added weight, added complexity, added cost... all for something so rare you'll be hit by lightning on the ground before the camera is ever useful. And what then? You still gotta land nosegear sideways
As always a nice and factual video without any lurid storytelling. Proper good job captain and crew! 👍🏻
Actually Airbus is planning of getting rid of all gears and switching to bare metal skis instead
I love the way you explain this, you're experience as a pilot helps to put it in another perspective.
11:30 How were they able to take off with a 90° nose wheel without noticing? That sounds really weird
Airbus has a lot of automation, and its controls in the flight deck is not physically connected. This probably reduces the feel of the aircraft since the computers are damping a lot of movements.
Having been a plane passenger only once, I find these videos informative - can't decide if I'm more anxious or more reassured after viewing them! Still, flying much safer than driving, for sure.
A humorous idea, print a shirt depicting the 90 degree front gear failure with text "another flawless landing"
Great video as always Petter! Question for the room here... is this an issue that has only affected the A320 or have similar issues affected other types?
Seems to me a very SIMPLE thing to do would be add a front landing gear camera. One that looks down at the gear once it is down and locked. This would at least tell the crew what the wheel is doing if they are getting the alarms. Cheap and simple add-on so at least they KNOW. It's not a fix for the issues, but no more fly-bys unless of course the cameras don't work. But, what do I know.....lol
Greg
Good idea but NOTHING in aviation mods is “cheap and simple” - although you would think so. To add a camera youd need to screen in the cockpit or modify software to allow camera to feed into a current screen. You’d have to have design testing and certification of the camera location and install. The camera would have to somehow not be blocked by dirt and debris = ground crew function between flights , etc etc etc. - makes some sense but not “cheap or simple”.
It's overall cheaper to simply ask people on the ground to report the condition on a low pass go-around. Compare the expense and resource requires as Marlin mentions to implement, plus the increased maintenance, vs the number of incidents. It's not a good business case to add weight, cost, complexity to this aircraft.
But the pilots aren't even supposed to do a flyby to let ATC visually confirm the orientation of the gear.
So it seems like the knowledge of the orientation of the gear is not that important for the pilots to have.
Otherwise a flyby would be mandatory whenever one of the faults is shown on the screens.
@@Jehty_ that has happened in at least some of these incidents though.
@@ChristopherBurtraw you mean a flyby?
Yeah, but as mentioned in this video the pilots are not supposed to do that.
Small nitpick, but it's caster, not camber, that naturally returns the nosewheel to the centered position.
Great video! Love your in-depth coverage of this.
Makes you glad to be flying a B737, doesn't it? Haha.
Thanks, when I heard "camber" I couldn't understand what was being described.
10:05 is it not better/safer to have the wheel locked at 90 degrees than having it at let's say 45 degrees? I mean , I think that at 45 degrees the plane would start steering as soon as it touches the runway and would end up on the grass , while on 90 degrees it think it's much easier for the pilots to keep the plane on the center linie.
Exactly. That is part of having a fail-safe design. Redundancy is the premise of every aircraft system.
Not so sure about that. In both cases the traction of the nose gear is going to be pretty much minimal, practically becoming a broken snowboard. Once the aircraft is touching down, the momentum (in terms of direction) is gonna be set and the aircraft is going to hold this direction till it has stopped. You can see this on intact gears too, once a certain speed it exceeded the tilt of the nose great will have minimal to none effect at all :)
@@dopepopeurban6129 What are you talking about? Anytime the nose gear is on the ground it has traction. The more it deviates from the center the more difficult it gets for the pilots to counter it with the rudder.
@@nurav_7 that’s physical bs. The higher the speed the less traction there is. Have you ever wondered by racing cars slow down before heading into a curve? - Because the cars can’t take the turn if they’re too fast. Their momentum in weight and speed is so high that their wheels aren’t able to turn the car in a normal gradient anymore aka the force of the cars combined speed and weight outmatches the resistance of the wheel - the traction - and thus lead to a loss of agility in steering. With your logic, these cars wouldn’t need to slow down before taking a curve and things like drifting would be impossible. That’s not how physics work.
@@dopepopeurban6129 I fly the damn A320 and I have seen this failure in the simulator. May I say more?
Another awesome video from Petter - very interesting!
Very interesting indeed Petter.
Further on Patreon.
Class completed.
Thank you Sean!
Very nice video again, thank you :)
There is only one thing I do not completely agree with you. And that is about (not) using ground spoilers during abnormal landing gear configuration. In my opinion the reason to not use spoilers is to prevent high pressure on the landing gears during rollout and reduce the risk of a collapse. Passenger evacuation is still possible even with the groundspoilers up. The evacuation route from the overwing exits towards the ground is very close to the fuselage and at that part of the wing, there are no spoilers.
I laughed so hard when you used a Desktop Power supply as your example for Incident 4
For constructive criticism, your luminance values seem off in their conversion. Specifically the @16:11 range forward, there are no luminance values under 16, and non above 235. This seems to indicate there's an error in 0-255->16-235 (or vise versa) conversion. This is as played in a web browser directly through youtube. Downloaded as an mp4 I can of course control this manually, but if I need to change it more than once per video there's an underlying issue.
The only thing I would like to have seen added to this is why is it just the A320 repeatedly having nose gear issues? How are other Airbus's and Boeing's designed differently that prevents it?
I doubt the A320 is having more nose gear issues than any other plane. If you watch the video closely, you see that there were six completely different failures, and the only reason they're in the same video is that they ended with the same symptom. On other planes, those completely different failures would have had completely different results and nobody would be saying "Aha! Pattern!"
Think about engine failures, for example. Sometimes it's because of a bird strike, sometimes it's volcanic dust, sometimes it's fuel starvation, sometimes it's a manufacturing issue with a turbine blade, sometimes it's improper maintenance, sometimes it's the pilots shutting down the wrong engine. It would be wrong to just focus on the common symptom of "the engine stopped working" and start asking "Why do plane engines keep failing?"
@@beeble2003 I think this question is very much directing into this pattern. I mean look at what people say about Boeing, regardless of the problems nature. Sad people just want to point fingers at other people instead of focusing on problems and solutions, the exact reason why any of these peeps aren’t suited for jobs within aviation industry lol
@@beeble2003 According to another post, the 737 mechanically locks the nose gear in place when airborne. When's the last time you heard of the 737 having this issue? (I guess Airbus could borrow this tech from Boeing in exchange for some help with 737 Max stability.)
@@joesterling4299 Problem is, the 737 gear is much too short to be applicable to a A320. 757 maybe?
@@joesterling4299 The last time I heard of a 737 having _which_ issue? The whole point is that these incidents all had different causes. There is not "an issue" -- there are several issues that have all caused the same symptom, so they look like a pattern (including maintenance failures, and pilots ignoring the manual and trying random sh*t to fix the plane). On the 737, an equal number of completely different issues manifest in completely different ways, so people don't see a pattern.
Again a perfect explanation. My compliments
Airbus nose gear centering mechanism is over-engineered.
The 737 has simple built in cams which mechanically engage and centers the nose gear as the nose gear becomes airborne.
It seems to me that it's wrongly engineered. The damn thing should get locked straight ahead in flight regardless of anything else. From what you said, I guess this is exactly what Boeing did with the 737.
You have no idea. Airbuses are ludicrously over-engineered and there is at least one computer for everything. Most of my time spent working on the Airbus is spent looking for the right circuit breaker to pull and reset to get the stupid computers working again.
@@singleproppilot Well, at least the stuff not one augmentation system on top of another
One could argue that, on the 737 Max, the lack of redundancy for the MCAS was a rather bad case of under-engineering.
@@StarHorseLover2012 That’s absolutely true, but that’s why the 737 MAX debacle was so shocking; it was a very rare misstep for Boeing engineering, and that decision appeared to be more cost-driven than usual. Usually their designs are very robust and fault tolerant. Historically, Boeing’s weakness has always been they put too much trust in their suppliers. They spec out parts for their airplanes, they probably award the bid on lowest price alone, and sometimes they get absolute junk for parts in return. Remember the 737 Classic rudder hardovers caused by jamming hydraulic servos built by Parker-Hannafin. They probably didn’t expect the Japanese made lithium batteries for the 787 to undergo thermal runaway, nor did they expect the 737 MAX angle-of-attack probes to be failing after mere months in service.
I've been building and repairing computers for 25+ years now and I've run into a number of situations where the standard procedures for a particular issue didn't fix the issue as it was something else causing the issue. You don't know how many times I've had to go against what I was taught because as you said "It may look like the cause is the same but it's not." On my midterm exam on my first year at a VoCal school, I faced an issue where a particular Windows installer file couldn't install this particular file as it kept failing a checksum check. I went thought the normal checklist of trying a different install CD, different CD-ROM drive, drive cable, etc. No matter what I tried that same file kept throwing up a checksum mismatch. The actual cause of the problem was one that neither myself nor my very experienced teacher had ever seen before for this particular issue, a defective RAM stick. My only assumption is that where the memory address that was defective just happened to be where the Windows installer wanted to expand that file into RAM and it somehow always went to that same address when trying to expand that particular file. Weird.
Well, scratch that "Instrumental in the design of the Airbus A320 Landing Gear System" bullet point off of the old resume.
Thanks for all the content I love it! Have you intentionally set this video to unlisted?
I think he has 😁
11:26: This is amazingly stupid. By telling me that the pilots ACTUALLY TOOK OFF with this fault, you're telling me that the pilots would have failed to notice the frictional grinding of the nose gear on the runway while at the same time failing to hear the bang from the rupturing tire as the pavement tore into the tire. Also the pilots would have had to fail to notice that the plane was not getting up to takeoff speed as fast as normal because of the friction of the locked nose gear with the runway. So then, you're telling me that with all the problems which a nose gear locked at a 90-degree angle would have caused, it STILL took a warning from the instrument panel for the pilots to know anything about it. That is mind boggling. Somebody in the cockpit had to be blind, deaf, or otherwise not doing their job --- which then raises the question of what kind of passenger wants to fly with pilots who can't even notice a locked nose gear while the plane is moving and taking off.
I mean, I'm pretty sure those engines put out enough thrust that they wouldn't really notice something like grinding down a wheel all that much. That's like expecting a gamer to notice the difference between 59 and 60 fps on a gsync display. I bet even air conditions make a bigger difference to engine performance than wasting a few lbs of thrust grinding a wheel down. Metal isn't exactly a 'grippy' material. If you've ever driven on rims or ground metal on a grinder, you'd know it's like ice skating compared to rubber tires.
The noise though... No idea. Maybe the cockpit is isolated enough it was barely any more noise over the engines. Maybe the tire rolled off the rim cleanly enough that there wasn't a sudden drop of the nose, either.
@@ashkebora7262 Well, maybe, but it's still good question material to talk about.
@@MyNathanking I just wish we could get some extra data on it. I tried looking up coeficients of friction, but metal on asphalt is around 0.7, which... is almost what rubber was listed at?? Must've been static friction, but being anywhere near rubber still seems pretty high to me.
The wheel was probably not at 90 degrees during takeoff but the faults that caused the wheel problem were there. Wheels don’t just turn at 90 degrees at takeoff, pretty sure the pilots had to taxi to the runway right?
@@DB-rc9ln He specifically says in the video the tight 180 to take off set it at 90 due to going past the 20-some degrees of turn.
most awesome aviation content on the web! thanks!
How in the world the pilots did not recognize taking off with gear at 90°? I bet the friction it creates at acceleration is huge!
I'm guessing the problem didn't start to happen until well into takeoff and not before the aircraft started rolling.
Insane list. This was the most thrilling Petter video I have seen this year. Thanks.
So do any other aircraft suffer similar n/w problems (as often) or are Airbus just particularly bad at n/w design? Even if the causes are different in each incident it just shows how many failure modes are in the original /redesigned system. How many others are there yet to be uncovered?
Can you explain what would happen if the plane needed a Go Around after the people have been moved to the back? On the Airbus website it says
"In case of go-around, setting TOGA power induces a significant pitch-up moment that needs to be compensated for. The more aft the CG, the bigger the pitch-up moment. If the CG is too far aft, and outside the envelope, the pitch-up moment induced by initiating the go-around may be too big to be compensated for. At low speed, high angle of attack and TOGA power, the pitch-up moment increase due to having a CG position too far aft, may also trigger the alpha floor protection, thus prevent its sufficient compensation."
Moving people to the back and reducing the landing speed sounds like it could come to a catastrophe if something else went wrong on approach and GA needs to be executed.
Wait what? They took off with the nose gear at 90°? That would have already half destroyed the nose gear even before they came in for an emergency landing. That landing must have been extra sketchy and dangerous, right?
I just thought of another reason to shut down the engines on landing if the nose gear is cocked sideways at 90 degrees. It doesn't take a collapse to send debris back towards the engines. That spark trail is made by debris coming off of the landing gear. Admittedly almost all the debris is very fine and won't do much damage. But there are going to be a few larger chunks that may come off as well. Including as likely candidates half lug studs, half lug nuts, half the axle, ball bearings, half of each rim and tire chunks.
My reasoning is that once slightly more than half of a bolt and nut are ground away there is little holding it in place. This makes it much more likely to come off and bounce into that trail of sparks.
I have done automobile maintenance but no aircraft maintenance. So a few things to note that almost any mechanic with experience will know. I am assuming that aircraft wheels are similar to automobile wheels (with more exotic materials on a larger scale). On a car the wheels are held on by a set of 2 part fasteners. There is a hole drilled and tapped into the hub. Into this hole is inserted a threaded stud. One end of the stud sticks out from the stud. The rim is placed over these studs so that they show through holes in the rim. These then have lug nuts tightened onto them. (Yes, I have replaced broken studs. It's a pain in the ass). The second is that sometimes the only way to get a REALLY stubborn but off is to use a nut splitter. A nut splitter uses a wedge driven by a bolt to crack a nut in half. Once split in half, the 2 halves will usually just fall off.
Great video, My career is as an Aircraft Technician. Sometimes all of these new designs and new issues make me wonder. The old designs worked for many years with minimum issues. If its not broke don't fix it. I enjoyed video fully. Keep them coming ❤️✈️ 🌎
New designs are for saving weight, space and other reasons. Its called evolution and some changes extinct.
Yeah I totally understand that. Less weight less fuel burning more passages and cargo more profits. Some times they just go way overboard. That also happens on internal parts of some Turbine engines too.
The A320 was certified in 1987. Hardly "new" anymore 😕
Oh ok thanks
I have done very little work on the A320 series, I would guess that it does not have a centering cam built into the strut since the BSCU moves it around before landing. Most, if not all aircraft I've worked on have a physical cam built into the nose strut that it will fall into when the strut is fully extended after take off. Is this a design that some of the other newer Airbus's have?
Not sure but it sounds logical
The Video is not listed for some reason
It’s not released yet, you can only reach it from Mentour Pilot and Patreon at the moment.
Woot, I've been waiting for this one. Thanks!
14:51 "A lot of sparks coming off the nose wheel, which would be normal"
When such an incident is so common that it gets referred to as normal... Maybe they could simply replace the whole nose gear with a wooden pole - cheaper to replace, less wear on the runway and possibly less potential for causing engine damage.
I love your idea!
It is good that investigations are carried out on all incidents and not relying on "we have seen this before, it must be XXXX". As you have showed in the nose wheel issue, the casual factors were all different. Alarms and warnings don't tell you why something happened, and in most cases what is wrong, what they tell tell you is that there is an issue with a component or there is an issue with the circuit (hydraulic, electric or cable controlled) and possibly the component.
While I 100% agree that following the relevant check lists, and agree this is the first thing to do, there have been many instances where Pilots have had to do their "own" thing, some if not all having been shown on your channel and others. IE the QANTAS QF32, Olympic Airways Flt 411, Air Canada Flt 143 (side slip like a glider) incidents and the list goes on. I know there is a greater risk when operating outside the published processes, however as long as they follow the process first (or attempt to), then sometimes the Pilots must use their experience, their experiences of the particular aircraft with it's own performance characteristics they are operating, knowledge of flight principles and whatever else is available to them to safely bring the aircraft down. I have no doubt that at the height of an incident, especially the three extreme examples I gave,, the cockpit can be a tense place, that's where we (the passengers) rely on the flight crews professionalism and ability to communicate to each other, because that is the greatest tool they have - each other in dealing with the issues at hand.
Ok... But even though all incidents were caused by some or totally different reasons, in the end what I'm seeing is a huge problem with the design of the entire front nose gear system that allows for many points of failure. Airbus should address it with a more radical solution than a few software tweaks and minor hardware adjustments and maintenance procedure instructions
The trouble with radical redesigns is that they're not only very expensive to do, but also that it's very difficult to validate that your design is safer, better, and more reliable than the previous one.
I work in the world of software, and radical redesigns of code are pretty rare in the enterprise world even though it's much cheaper to do this in software than hardware. This is mainly because it's difficult to justify changing critical components in a radical fashion unless you not only have a strong justification for it, but also sufficient metrics and testing around it to ensure you don't actually see regressions in the functionality and performance of that component. Design is hard, and regressions are actually very common when even doing minor refactors.
I can only imagine this is even more true in the world of hardware. We might have over 300 tests for a single component, and in software those tests are cheap to run. In hardware land, physical tests are very expensive and may even be infeasible for certain scenarios. I'm sure they did a lot of simulator testing too, but you never will know how exactly it'll perform until it's in the real world being used.
There's a reason why the phrase "better the devil you know" is often used. A radical redesign might sound good on paper, but in fact could introduce a whole new class of failures that now no one expects to see. Confusion between maintaining the different types of landing gears could introduce weird issues that the manufacturer never expected. Even if the design as-is clearly has some faults, the relative rarity of those faults still means that it's a functional design that is safe for flight. It's not worth the massive risk to throw all that away for something completely new.
@@MNGoldenEagle yes, but it's also important not to go too far in the other direction. An extreme example was the Therac-25 radiotherapy machine, which killed six patients while the manufacturer and technicians tried one little thing after another to paper over a fundamentally dangerous design. Even in lower stakes situations, a poor initial design can lead to extremely expensive technical debt; a full rewrite may be the best and cheapest option.
@@MNGoldenEagle but we are talking about aviation. It's famous for being all about safety and this whole issue seems all but safe. The design has to have critical flaws if so much stuff can lead to the same failure. Fortunately, any of the incidents have turned into fatal accidents so far, but we've seen previous events in which a failure in the landing gear can lead to debri punching into the aircraft's fuselage and leading to much more severe damage and even fatalities.
Could you start the apu just be for landing for the power supply?
Does this happen with any other planes at nearly this frequency or is there something about the design of this nose gear and its sensors that makes it basically default to 90 degrees off center when something goes wrong?
Love this format. Y'all are killing it!
نعم هذا هو السبب
😹😹
2:56 it’s like me OCD jiggling my door handle when I lock up making sure the door is shut and locked properly! Maybe I need some recoding…. lol
Wow, this is actually really funny. Like, yes, there is potentially a lot of stress for the pilots and passengers involved but there's also something funny about this recurring failure. I can just imagine Airbus engineers sitting their going, "Oh, here we go, it's the nose wheel steering again!"
especially for the engineer that "owns" that system
@@jamescollier3 Horrible work silos 🤢
Nose wheel steering uses opposing hydraulics. Loss of hydraulic pressure on one side has the same effect as actuating pressure on the alternate side. Either pump or it’s electrical connection can cause the nose wheel to do that.
I enjoy air crash investigations. They are very thorough and I always feel satisfied after going through Mentour Pilot's explanations. But not this one.
I understand the cause were different for each case. But there are serious questions still unanswered. Why only A320? Why the nose gear aren't resistant to water? Does that mean it is unsafe to lower the nose gear in the rain? Why they are not grounded? Does someone have to die first before a more drastic action is taken? Is this a clue that there is a bigger organizational problem hidden within the Airbus?
Remember that these are 5 isolated incidents separated by close to 20 years caused by different problems.
Don’t be to quick to judge.
Unfortunately Mentour's click-baity headline has encouraged the packs of keyboard warriors and seat-flying experts to see scattered incidents as an epidemic.
"Why only the A320"? It isn't "only" the A320. Pick your plane, you could do the same for any common type.
A quick Google tells me that the 737 Classic (2000 produced) had 23 main gear failures in 17 years. "Why they are not grounded? Does someone have to die first before a more drastic action is taken?" etc and so on ad infinitum.
@@MentourNow I will ask you then who was quick to judge when my comment "Why am I not surprised a computer created a problem where there was none? I wonder how many of these airplanes will still be flying in 20 years." was censored?
Reminds me of a structural engineer I knew who was tasked to design a structural support in a large jet’s wing. Another engineer was tasked with designing the next support over in the wing, a third engineer did the next support, etc. None of the engineers shared how they were designing their respective support. That project didn’t even involve a computer controller, which complicates safe design. Why the company chose to silo the component designs is beyond me.
it's beginning to seem like this would be a good candidate for a monitor camera to be installed in the landing gear bay.
Those instructions in the "extra section" towards the end of your description of the check lists, just before showing the latest video, were exactly what the pilots did in your big story about the Jet Blue incident on the other channel. Move passengers back, "brace", etc., etc., etc. It underlines just how brilliantly that crew acted - they didn't just go "by the book", they effectively wrote it!
Even though each problem you described was different, it does seem to me - a total layman when it comes to engineering! - that the whole nose wheel array (internally and externally, hardware and software) should be redesigned. There _shouldn't_ be so many possible faults, at least that's how it seems to me.
Had one of the earliest incidents ended tragically, I do wonder if the authorities would demand a redesign, especially if there had already been a few, benign, occurrences. I'm obviously relieved that no one has been hurt by the recurring outcomes of so many incidents, but that does leave me wondering if the problems are being taken seriously enough.
What if a landing needs to take place on a wet runway? The "let it roll to a stop" method could well end up with a plane running off the runway and onto potentially hazardous terrain. I dread to think of the outcome should that happen.
Fascinating as ever, Petter. Thank you so much for your excellent work.
Wow - taking off with hose gear at 90! That had to be a helluva ride 🤪
Yes, it is just madness to operate a plane in that condition.
So this happens with some infrequency. When it does happen, is the runway repair bill automatically charged to Airbus if it’s not a maintenance infraction?
Curious why more Airliners don't have outboard cams to help in these situations
Most autos do
Cuz of certification, lighting, checklist procedures, pilot training, implementation, regulation and development cost. It’s far more complicated than just taping a GoPro into the gear bay and sticking a monitor to the other end of the cable.
@@dopepopeurban6129 Its possible, irc a380 have cams for PMC (Passenger Media Center), we used cams when CRT was in prime
Most autos aren't flying at 600mph in thin air where aerodynamics matter a lot.
@@etherealrose2139 That's a problem for engineers, and easily solvable
See A380
Rockets have external cams for example
@@mateuszzimon8216 yea but I don’t see the benefit there. One way or another the pilots will know that something happened to the nose gear and a 90* rotation rly isn’t the end of the world. The gear is gonna be broken for sure after landing but the aircraft will come down safely.
your transitions on this video are really bright... playing hell with my headache 😫
It's these new-fangled systems that are causing these problems. Consider that the ever-popular DC-3 has NEVER had a nosewheel steering problem in the 85 years it has been flying. Maybe those old guys weren't so dumb.
That's because the DC3 does not have a nose wheel!
@@GTRider69 it can't be problematic if it doesn't exist!
fantastic explanations as always, Petter! Love it!
It feels like most issues are a result of an over engineered nose gear system
As usual, an interesting video, captain!!
I understand each incident was caused by differing faults and or failures. However in my opinion the front nose gears overall design is not the best example of aircraft mechanical engineering. I don't believe because each incidents causes are somewhat different they should be written off as coincidences. Airbus should consider a more thorough engineering review of the complete system as a whole. Thanks for bringing us the story's and as always well done.
In 2000, i worked in a tall office building beside LAX and we went outside to witness the aircraft landing with its nosegear at 90deg.
Unfortunately i cant find the plane type as your video made me wonder if it was the same as the more recnnt aircraft.
I was wondering why they couldnt turn on the APU rather than rely on a ramjet which itself might impact the rumway? Thats what i would do if i were pilot. Shut it off after coming to a stop on the runway before evacuation (or during because its intake wouldnt risk any passengers).
Another thing i firmly believe is that every control shpuld hace feedback. If rhe Captai s steering hamdle were at 90deg it would be an easy indicator what the wheel is doing.
Without feedback you cant even walk. You wouldnt know if your foot was on the floor or bumped into a wall as you continued the motions.
Feedback is essential which is why they call it AI.