I remember as a kid watching in Bishop Ca, a contract pilot showing off in a Turbine Aero Commander make a high speed run down the runway then pulling up hard. The mechanic the next day noticed fuel leaking out of the left wing. Measuring the wing tips, the left wing was 9 inches higher off the ground and the top of the wing was wrinkled. He was no longer a contract pilot.
The only Pilot that knew how to fly an Aero Commander with amazing feats was Bob Hoover. RIP. His plane now sits in the Smithsonian. What an awesome pilot.
At Bishop i saw a Lear type private jet that was ruined when the pilots were screwing around came over the sierras crest and got caught up in the sierra wave(140 mph jet stream winds)--it bent the jet and they were able to emergency land at Bishop--i heard the jet was totaled
Many years ago ('94-'95), as a young A&P, we had a Pawnee with Hutch metal wings that were just full of cracks. We pulled the wings to repair them and found the fuselage wing attach points badly rusted internally. They looked great with nice paint on the outside, but just ugly inside with much material missing. It left on a truck to an aerospace welding facility for replacement. Scary stuff considering how they get yanked and banked in a highly corrosive environment.
@@shable1436 we had a water tank like that at work. you knew the metal had gone through when you saw the bubble in the paint. then we used to just drill it out and stick a nut and bolt in with a rubber washer.
the glory[& FAILS] always shines on the OPERATORS/pilots but, the MECHANICS and all that attached to support their mission[s] really is so important......maybe more so [idk4sure] OPERATORS are the ones also in the line of weather a vehicle or equipment is safe too operate. So it maybe would[have] passed PILOT pre-flight inspection but really it is a TEAM that creates the missions capability to be a success as in returning. The total success ends with safe return. Thanks Juan,great report w\insights Semper Prorsum ~ Godspeed
I had to rewatch the part about why maneuvering speed decreases with weight... I don't know if I'm the only one who got a little lost, but I could still use a deeper dive into the physics. I appreciated that you explained it multiple ways, but for some reason it's still not clicking for me. Thank you for diving into these tragic events so that we can all learn to be better and safer pilots.
If Juan is reading this I agree. I do not refute anything in the video, but clarification on the physics of why this happens would be good. There is a detailed comment above this one that goes into how lower weight makes the airplane more nimble, and therefore able to apply more stress to the airframe. This feels right intuitively, but hearing it from a pilot would be cool.
@@kingsizedmidget7294 I was doing some reading just now and while there's a lot of talk about critical angles of attack, weight, etc, I think distilling it down to the nature of flight helped me understand it better: Flight is overcoming gravity. At straight and level flight, you are always pulling 1G. You are in balance with gravity because you are producing 1G of upward lift to counteract Earth's 1G of downward pull. When you start to climb, you pull more than 1G, because you're overcoming gravity. To generate 1G of lift in a heavy plane, you need a higher angle of attack from your wing than if you were lighter. If you suddenly dump a lot of weight, your lift is going to go up at any given angle of attack (in the same way that taking off in a heavy plane will have a more sluggish climb, taking off in a light one will have a much faster climb). So when a plane dumps a lot of water in the air while pulling some number of Gs, it will now generate more lift at that same angle of attack, which means more Gs. So what was a 4G maneuver becomes, say, a 6G or an 8G maneuver, then your wings rip off.
The way I heard it put is a heavy load will stall. A lighter load can generate more lift before the stall and thereby more stress on the frame. Think of the Va stall as a safety valve that dumps excess lift. The wings will eventually create the extra lift, but the frame can’t spread the lift. Even if the struts and spar distribute the force to the frame, now the engine mount is overstressed with its heavy load.
It’s because he’s looking at a case where the wing attachment failed, but then explains how the wing loading actually goes down. At 6:39 he briefly explains it’s not the wings that are overstressed by this issue, but the same wing loading applies higher Gs which can break other things. It’s just a bad example for the issue being explained.
Juan, let me add some details from my experience working as a aircraft structures certification engineer: It is true that the maneuvering speed vA is defined by vS times the square rout of the design load factor. However, it is not a limit up to which the pilot cannot damage the airplane. vS is a calculated stalling speed (FAR/CS 23.335(c)), as estimated early in the design process. vA is a defined airspeed limitation to be used mainly for control surface and control system structural sizing. FAA AC 23-19A explains: "VA should not be interpreted as a speed that would permit the pilot unrestricted flight-control movement without exceeding airplane structural limits, nor should it be interpreted as a gust penetration speed." The TCDS you present in this video is of a restricted category aircraft. Although limit maneuvering load factors seem not to be mentioned in this TCDS, in the restricted category certain limitations can be lowered below the FAR-/CS-23 minimum requirements, including limit load factors and structural safety margins. That is especially used for cropdusters to allow higher take off masses. As far as wing structural loading is concerned: it does actually not change when you empty the hopper tank. Given, that speed and angle of attack stay the same. Why is that? The aerodynamic forces on the wing are unchanged as long as airspeed, angle of attack and it's configuration (flaps, ailerons) don't change. So the lift force doesn't change. The same lift force acting on a lighter fuselage lighter than before means the vertical acceleration increased, as Newton claims in his second law. To maintain level flight, i.e. maintain 1g, the pilot needs to reduce the angle of attack during release of the payload, as you explain. It seems that the unlucky pilot in the video did the opposite and increased the angle of attack, leading to increased lift forces, which resulted in structural failure of the wing.
I was a structural tech for a while and completely agree with this comment. Pilots need to stick to talking about flying. They also have a bad habit of blaming pilots only. This is not the first time wings have failed in Mexico… Mexico is known for ignoring maintenance and inspections. I’m fairly confident a properly maintained aircraft would have survived that. I see those duster fly really hard in the states all the time and no issues.
If you go to 8:12 and change the setting to 0.25 playback speed, there's a moment right around 8:14 where you see the wing fold back diagonally. At least intuitively, it seems to me that this supports what you're saying. It's reminiscent of the silly game we'd play as kids, sticking our hand out of a high speed car and "surfing" - once the angle goes a tiny bit too high, the effect snowballs as the wing flips up and back.
Coming from a third generation ag pilot, great break down of this accident a lot of people misunderstand accidents in the ag world. Although mistakes were made, I am also leaning to the fact there was probably corrosion involved. Great job Juan keep up the good work.
Agreed. I’m imagining crumbling white spalling at the attachment. Decades of hard work, likely living outside, previous over stress and possible neglect. Condolences to the family(s).
@@davidfrench5407he probably didn’t pull up. He just didn’t nose down while he was dumping. Most of the time you’d never pull the dump handle coming out of a dive and at high speed. You wouldn’t shed weight in an emergency under those circumstances in very many situations. I started my ag flying career in an O-320 150 hp Pawnee before I moved to an O-470 Ag Wagon and later an O-520 Ag Wagon.
@@JoshJones-xd5mw from that angle he would have at least been conscious that he was heading toward a tree line. Tragic regardless of the exact cause, hopefully others can learn from this.
Wow, what an educational video. That explains why there are several videos floating around the web showing structural failure AFTER dumping the load. Never made sense to me, but now I understand. I am a commercial pilot, helicopter, multi-engine, instrument rated, as well as A&P mechanic (all in the past, I am 80 years old). I was always keenly interested in areodynamics, and so am really grateful for your explanation of maneuvering speed dependence upon wing loading. As an A&P, I have performed the wing spar attach AD you talk about. I always liked the Pawnee 235, a very smooth and capable airplane, and a shame to see one lost. Thanks again.
While it is true that low weight does increase max Gs for the same control input at any given speed, the lift of the wings and so the couple at the wings roots is the same, so I don't see how low weight can be to blame for this kind of structural failure. Other parts of the airframe indeed are more stressed with more Gs, but not the wings because of this low weight situation. Thanks for your response, it meens a lot for us GA pilots your videos. Congrats.
Lightly loaded, the wings can produce more lift before stalling because it has more available angle of attack. The way I heard it put is a heavy load will stall. A lighter load can generate more lift before the stall and thereby more stress on the frame. Think of the Va stall as a safety valve that dumps excess lift. The wings will eventually create the extra lift, but the frame can’t spread the lift. Even if the struts and spar distribute the force to the frame, now the engine mount is overstressed with its heavy load.
I had seen personally three of that aircraft in the early 70's where the tubing next to the tail wheel was corroding apart from the chemicals, speaking of such, why would anyone, especially pregnant, want pesticides and defoliant tank water to be dropped on them???
Anyone who wants this kind of nonsense for a 'gender reveal' probably has a IQ so low that they struggle with any concept above 'Whoo pink pretty stuff'
Thanks! There are numerous Airworthiness Directives on the struts, the one you showed for the main spar attachment and another for the aft spar attach. It does not look like either of those failed. As you mentioned, it does appear that the left wing failed at the outboard strut attach point. I’ve not done crop dusting with these birds, but I do have over 600hrs in Pawnees on glider tow duty. We are about 1200# below MaxGW. You are hard pressed to get over 120mph in a dive without that extra weight.
I used to fly the Pawnee (later the Canso) spraying in Africa, in the 70s. It is now a nostalgic chapter of my life and I found this video both illuminating and sad. Thanks Juan, you ALWAYS produce such high value information. Pilots would do well to follow EVERY ONE of your videos. Thank you.
As I recall… during the low level skip-bombing assault on the Ruhr Valley Dams during WWII, 5 of the 8 attempts resulted in loss of aircraft to both defensive gunnery and catastrophic structural failures.
I have a small 2x2” piece of “AJE” , a Lancaster lost on the dambusters mission, AKA “operation chastise” … flown by Flt. Lt. Norman Barlow and his crew, lost to ground fire at 23:50 hrs May 16-17 1943… Godspeed boys…..
Only one aircraft was lost over the dams, that happened at the Mohne dam. It pulled up but one wing was on fire and it broke up and crashed. The Eeder dam did not have defences. The aircraft that had to attack that dam all pulled up very steeply but none broke up.
@@chriss.4147 He could be talking about training / testing too. There's film of a least one where the bomb bounced into the tail and the aircraft went straight into the sea.
I have always loved aircraft but I am not a pilot. This is an excellent reminder to me why I should never try to fly. The details that must be remembered around the weight, G-force, stall speed, etc... are not my strong suit. Would love to be a mechanic again, but you guys that are (good) pilots get all my respect.
I fly SEATs and I can tell you that the airplane does pitch up when the load comes off. If you ever watch a cockpit view you’ll see the pilot push the stick forward (full forward for a salvo). I think the pilot wasn’t ready for the pitch up, was well above ideal drop speed, and the rapid increase in G’s caused structural failure. Keep in mind that the wings are producing around 2900lbs of lift at that airspeed and pitch angle. When the plane loses, let’s say 1000lbs within a few seconds the excess lift causes the plane to pitch up rapidly. If you aren’t ready to counter that with forward stick, you will find yourself behind the plane. This tendency only increases with speed.
As to the manuevering speed- weight relation - you can think about the ratio of your stall AoA and level flight AoA as the approximate max gload physically possible at given speed. To keep it below the airframe max gload, you want to keep a given minimum AoA in level flight, regardless of weight. To do that, you need to limit your speed, and that limit is higher when you are heavier.
If the hopper is forward of CG as it appears to be, isn't it possible the plane abruptly pitched up in response to the much lighter nose of the plane? The pilot may not have had training or ever practiced an emergency dump and would not have known to pitch hard down while dumping.
I remember a story my old C.O. told me, he was a young Buccaneer pilot on a squadron learning how to do toss bombing, only the airspeed indicator was not correctly calibrated and showing 20kts slower. Long and the short of it, coming in hot and releasing 2 1000lb iron bombs there was a slightly louder than normal thump and jolt only for his navigator to point out various bits of the aircraft where falling off as they where over g'ing the aircraft. 550kts, 200ft with what was supposed to be a 3g pull up.
Maybe another less counter-intuitive way to look at this is that for a given fixed wing load in this scenario, the rate at which the pitch changes will increase as the weight decreases. Classic F=ma. Less weight results in greater acceleration. Initially the rate of pitch was probably ok, but as the water exited, the rate progressively increased until the thing just about went vertical at the end and ripped the wings off.
I can from the good instruction see the pilot exceeded some limit but I still suspect a problem wing fitting probably waiting for a long time to fail..
I’m about to find out the gender of my baby. I’m gonna use this thing called my my mouth and vocal chords to reveal the gender to my friends and family.
It was very briefly mentioned, but can we also highlight the fact of how low his altitude was. From the video it shows his altitude was lower than the palm tree tops he crashed over. I believe this was a panicked pilot that pitched way too hard when he realized his mistake and simply overstressed the wings. It wasn't G-force that broke the wing. At that speed and very high angle of attack the wings were acting as an "air brake" at that point and simply broke off.
I believe the compression struts of the Pawnee don't help much. They have a big internal stiffening beam, but all the same I don't think the failure behaviour is the same when the failure mode is buckling instead of stretching, and effectively there is no or little yield phase where you merely bend things. Once the strut starts to buckle and bend off axis, and the load is still there, that's it that's all.
I'm struggling to make sense of this. The graph is for fully loaded performance, so let's say under these conditions it can handle 4 g's which produces 16k lb of wing load. When the aircraft is fully unloaded, it seems to no longer be appropriate to use the fully loaded graph anymore. You would need to check against the unloaded performance graph. However if you remade the graph for an unloaded aircraft, all of the points may change, so the 4 g's likely would no longer be the threshold. It might now take 8 g's to produce the same wing loading. So the theory of the video seems to be that the aircraft was at a safe point on the graph, and after unloading, the safe point on the loaded graph instantly represented a break point on the unloaded graph. The force is an aerodynamic force which is based on drag and lift, not mass. The force is based on geometry. When the mass is suddenly decreased, F=ma would say for a constant aerodynamic force, a sudden decrease in mass will be countered by an equal and opposite increase in acceleration. But again it does not seem to be appropriate to compare this new g value against the fully loaded chart. What it looks like happened to me is that the sudden acceleration increase caused by dropping the mass caused the aircraft to nose up beyond the desired angle of attack of the pilot. This uncontrolled increase in angle of attack caused an absolute increase in wing load. So it's not that for a load of 16k lb, the drop in mass caused g's to shoot from 4 to 8g's at the constant wing load, but that the additional increase in aoa caused the 16k lb load to increase to 25k lb, and the 4g's shot up to 12 g's, something like that.
I don’t get gender reveal parties. I really don’t. I would better understand if like one of the options was certain death. But all it really is blue for boy and pink for girl whoopee.
That seems completely counterintuitive that the lighter the load, the slower the maneuvering speed. I have zero experience with aviation, but that graph and your explanation were excellent. Thanks. And gender reveal parts are pure cancer. Why anyone wants to know the gender before the birth I don't understand. What does it matter. There are so few nice surprises in life why deprive yourself of one of the best. Most surprises are terrible news.
I had no idea manuvering speed would decrease with lower weight. I honestly dont understand why. I can understand that manuvering speed would stay the same even when lightly loaded but I dont see how it could decrease. Am i missing something?
It seemslike ground attack pilots would encounter the same issues when dropping bombs, especially old dive bombers. Are they just massively stronger structures?
The easiest way to ‘stack the odds’ in your favor is by starting any drop run well below maneuvering speed, this way you give yourself plenty safe margin even for a poorly executed technique. This should have been a fun event which certainly didn’t require a ‘high speed’ pass to ‘prove a point’… just very sad and completely avoidable and unnecessary 🤦♀️
Interesting & complex incident most of us aviators should learn from and understand. Having said this, the aircraft being outside the envelope of it’s maneuvering speed, is NOT what caused the structure of the wing to fail. Can anyone explain why?
The wing transitioned from airfoil to air-brake in a few seconds. Analogous to suddenly doubling air mass density during a pitch maneuver, pitch rate will double. Or at least the force generated by the control surfaces responsible for the pitch moment will double. During the transient the structure may yield under the suddenly increased load. Well outside the safe flight envelope into an unstable regime tragically in this case.
I've been curious as I've been watching the incident over and over how much the pilot actually pulled back on the stick. Wouldn't dumping that much load that suddenly, and that far forward of the CG, coupled with not enough experience and that high a ground speed cause the same reaction in the plane?
Damn, plane folds up, crashes and camera turns back, they keep celebrating like nobody just died in front of them…. Hugging, cheering. That’s f***ed up.
Aside from everything else, dropping 1200lb of water over/onto a crowd of people is incredibly dangerous in and of itself. Water has significant mass and being hit with such a large volume of water at so great a speed, without giving the water sufficient time to disperse , could very well cause serious injury.
PSA: Stop the gender reveals. This one was especially stupid. But anyone who hikes also knows how many forests and lakes are being ruined by mylar balloons and glitter that people just explode and leave. I can't tell you how many times I've been walking a lake trail and there's another mylar balloon and glitter contaminating an area the size of a sports field. Babies don't have gender anyway but that's a whole dictionary argument. Babies have biological sex and people aren't comfortable in English because we use the same word for biological sex as for mating. So they say gender. But "my baby has boy gender" is like saying "my unborn fetus likes to grow a full beard and work on cars". It's nonsense. So this whole thing is dumb and bad. The whole industry needs to stop. Party stores and catering companies are just making so much money. Meanwhile dozens die in fires, crashes...
I began my ag flying career flying the Pawnee and I never flew with more than 100 gallons. Never filled the hopper with liquid but we used the large hopper for dry fertilizer. I was trained at Ayers Corp. in Albany Georgia, where they make the thrush aircraft. You had to do a demonstration flight to get certified FAR 137 and part of the flight was a emergency dump. You had to learn to push the stick forward hard to keep the aircraft level cause dumping that much weight the aircraft wanted to climb like all get out.
The Pawnee pitch trim system was simple but not comfortable. A large spring on one end of a lever in the back of the fuselage attaches to a cable that attaches to the stick just above the pivot point. Moving the trim handle aft pulls, through another cable, the spring lever to tighten the spring and provide pull on the stick. Forward on the trim handle will slacken the tension on the spring and allow the nose to go down. Taking off with 150 gallons, usually the load is less for DA, will require a strong pull on the stick which the trim spring will help with. Emergency dumping with full aft trim will result in a significant pitch up unless the pilot pushes forward on the stick. The dump gate in the bottom of the hopper, also used to release dry material through a slim crack, allows slow release of liquid material as well. Liquid goes to the pump on a spray rig through a hose. The pilot may have been startled by the rapid pitch up of a full dump lever travel, fully open gate, dump. Or he may have been going for a spectacular pitch up. Or both. I personally know of two practice emergency dump fatalities.
@@gomertube I understand your comment - but a Crop Duster doesn't dump his whole load in one shot, it's sprayed in a fine mist. Which means that he's not experiencing a massive change in wing loading and Center of Gravity displacement.
Retired ag pilot here. I started out in a Pawnee 260 C model. It would carry the 150 gallons, I doubt that the 235 version could. That being said, I didn’t notice you saying anything about the hopper being well forward of the CG. I’ve dumped many times. There’s always a violent pitch up if you’re not trimmed in advance for it. If he also pulled back at the same time, then that would certainly overstress the aircraft. As previously mentioned, corrosion was probably involved.
I used to fly PBY water bombers and we called it “checking forward” as we dropped the load. With practice, you could time it just right, so you wouldn’t even feel the load being dropped.
My grandfather flew PBYs in WWII. I was about 10 when he passed away, I wish I could remember his stories. I remember one where they ended up damaging a wing dropping depth charges
I watched that maneuver from the ground as a firefighter in So. California. The large plane was almost vertical before it passed over a ridge, dump his phoscheck and dropped straight down the 3000 foot mountain. He missed the ridge by about 50 feet. Most of the pilots back in the 80's were ex-military guys.
@juliogonzo2718 gathering of the eagles web page has some stories. Major Jack Randolph Cram (USMC), was the personal pilot of Marine Gen. Roy Geiger's PBY-5A, the "Blue Goose." On 15 Oct 1942, he won the Navy Cross and permanent nickname " Mad Jack" in operations at Guadalcanal. There's a great story of Cram rigging that PBY with torpedoes and dive bombing Japanese ships. J R Cram was my grandfather's cousin. I met him when I was eleven years old in 1967. I believe he was working in DC at the time. He had a large great Dane named Ace that my sisters and I got to play with.❤
That’s really cool. Where did you fly? I would really like to know more about pby water bombers. The old Martin mars often flew over my home as a child.
These crop dusters are loaded to cover several fields before they need to be reloaded. The emergency dump is used if you have a in flight emergency and have to take weight off of the air frame for an emergency landing.
So the person filming the accident follows the plane up until the wing breaks and the plane disappears from line of sight then turns the camera back on the couple hugging and keeps it there like nothing ever happend? RIP to pilot.
I’m probably in the minority but I think that gender reveals are a stupid, look at me act. I remember a few years ago at least one of them started a forest fire that burned multiple houses to the ground. Why don’t people just wait until the child is born and announce its gender then?
0:17 I love how whoever is operating the camera paid enough attention to the plane to stay with it as the wings fold, but then just pans back to the soon-to-be parents as if they didn't just see what we all saw. "Screw that guy... it's a girl!" 🤔🤨
It probably didn't even register in their mind what just happened. That plane was literally flying by. 100+ mph. They just swung the camera back behind them and then right back to the over-spending, braggadocios couple.
I doubt very seriously that anyone was aware of the tragedy that just happened. I would love to see video of the next 5-10 minutes. My guess is that the mood changed drastically once reality sank in.
They were watch the video of it right when the wing bends there is a terrified high pitched scream followed by a glimpse of people running away towards it, people were absolutely aware of what happened the second it happened and the cameraman had a perfect view so put two and two together
Maybe, but the manoeuvre itself was pretty crazy too, I'm not an expert by any means but I would wonder how much of a difference that might make when the pilot put the plane under such forces in the first place. The wing might have snapped regardless of any wear and tear. If it is a factor, I'd expect it to be a footnote rather than anything that significantly contributed to this outcome.
@IrishmanAC many Ag pilots pull off these maneuvers several times on a daily basis. I have witnessed iy many times here in Ohio. I feel this pilot miscalculated his load and attempted a maneuver he was used to. A miscalculated load, and a potentially structurally weakened aircraft lead to this.
@@pennhiker5117 yes, it does. Unfortunately there are those owner/pilots out there that think it'll be ok unless they get caught. Sad but true. It happens a lot in the private aviation field and really is scary.. that said, I don't mean to accuse the pilot in the video.
They wanted to hire a stunt plane for their party. I don’t have an issue with that. At the end of the day the pilot needs to make the choices for safety of their aircraft. Blaming the couple for this is just silly.
Because people want to make a big deal and post it on social media. Narcissistic behavior while people die, houses burn, forests burn and people get maimed for these stupid stunts. Boy or girl who cares!!!
Juan with a PHD level lecture. No distractions no opinions no judgments, stayed on topic with serious attitude, as it deserves. Operating an aircraft or any other vehicle that may hurt or kill someone deserves to be taken with the most high responsibility.
I’m not a pilot, but I watch these for precisely that reason. These people have a responsibility to themselves, especially to their passengers, and to the rest of us on the ground to analyze these events and learn the lessons. Juan hosts an excellent channel.
@m.lozano9970 @Brotha00 Former railroad conductor here. I totally agree. When I was a railroad conductor, I took safety really seriously! The safety of my train crew and train passengers was my first concern. I don't like seeing preventable accidents like this. If something like this happened on the railroad, there would definitely be a rulebook violation. Someone would get fired. If you don't follow the rules and don't safely operate heavy equipment, things go wrong! That's why I followed the rulebook every trip, every time. I decided to switch jobs from being a railroad conductor. It was enjoyable, but highly stressful. I'm glad I pulled the pin when I did. It takes a toll on a person. I wanted a slower pace of life. I'm now a farmhand on a 7 generation family farm in Oregon.
I have much respect for Juan and his factual reporting combined with real experience analysis. It's really sad that this pilot lost his/her life during yet another stupid "baby gender reveal" party. RIP pilot, and sincere condolences to your family and friends.
The title of the video almost made me skip it entirely. Then I saw it was Blancolirio. Oh! Not the crap I was expecting. Glad I caught on quickly. Great coverage from Juan as usual.
Dumping the hopper causes an extreme nose up trim, it will take you by surprise if your not ready for it. A massive push on the stick is required during the dump. I am guessing he was a banner or glider tow pilot, not an ag pilot.
Thanks, that fits much better to what the accident video shows than Juan's explanation. Reducing weight (e.g. by dumping cargo) while in a turn with a constant wing-loading will increase the g-force on the aircraft, which can cause structural failure. But in that case it wouldn't be the wings that fail, those are at a constant load as we said. What would fail are the "fixed weight components", i.e. the high gees would rip the engine off its mountings or so. What happened in the accident video was that the aircraft pitched up massively as the hopper was dumped. As Juan explained, at lower air-speed that would have led to a stall instead of a structural failure, but I don't believe the pilot intended to put the aircraft into a stall so close to the ground. So an unexpected change in trim that caused the nose to pitch up is a more likely explanation.
@@DrAHorn The final picture in the video is stopped at exactly where the wing failed. You can clearly see it twisting as the attachment point failed. So the wing was fine. Just it decided to go one direction and the body another. With a poor couple of bolts left somewhere in the middle.
@@josephoberlander Well, O.K. it may technically not be the wing. But it's still part of the structure that is engineered to support the full force that the wings can carry.
@@DrAHorn True. It does look like it failed a bit earlier than it should have, but such are old machines. A little deformation, a loose bolt, a bit of rust and it could be still up to spec but just barely/needing replacement soon. It will get interesting to see what the reports say about the condition of it and the maintainence recrords.
It's amazing to me the lengths ppl will go to reveal a gender of a baby. Pilot killed, wild fire started and so on so on. Call or text your friends it a boy or girl. Ppl died because of this nonsense, enough all ready
This is again a sad story where pilots are pushed towards being a “flying circus” with a bad outcome. I will file this video for all my aerobatic, UPRT or instructor students, when I’m desperately try to explain a flight envelope. Thank you Juan for doing it for me! I like the visualisation with different colours. 👍🏻
Excellent video as usual! As a sometimes-getting-paid-for-it aerodynamics by training Ph.D. I view this through the basic physics lens. The force on the wings is proportional to the AoA and square of the airspeed (hence the exponentially rising limit curve vs. air speed). For a given speed, at heavy weight when you pull back on the stick the airplane cannot increase it's angle of attack quickly due to the airframe/load inertia and thus the rise in force on the wings is slow. At low weight when you pull back on the stick the AoA can rapidly increase because of the lower inertia/weight and quickly get to the point of generating a huge amount of force that's trying to yank the rest of the plane upward. Ever put your hand out the car window like an airplane wing and tilt it upward a little too much too quickly and your hand snaps upwards. If your hand was made of lead it would snap upward far more slowly than your water-ish made hand. That and the heavy plane/hand was already at a higher angle of attack to counter the aircraft weight/hand weight to keep it in the air. Ever see a light paper/balsa wood airplane suddenly get too much lift it pitches up very quickly whereas a heavier paper airplane does not pitch up nearly as fast. Excellent video as usual.
Ok that makes sense. I was about to rewatch the video. I was also wondering if destructive oscillation could be a factor as the wing load drops quickly as the water is dumped then loaded quickly when the pilot pulled up?
Thank you for confirming the reason for the "low weight" limits on maneuvering speed. This is the same reason why some friends who work as maintenance/defense contractors warn pilots to be extremely careful when flying aircraft on short ferry flights. Minimal fuel, no pax or cargo (or wing ordinance!) the jet will respond very differently than it normally does, and this is especially noticeable on takeoff as the jet will accelerate quickly, and overspeed the gear and flaps, etc. and a sudden pitch up, is at high risk of exceeding limits. Another risk for inexperienced pilots is scraping the tail on the runway.
Excellent explanation. Thank you, from one PhD (in an entirely different field) to another. I’m a student of aerodynamics as a hobby, especially low-speed aerodynamics for soaring and the use of negative flaps (“drag buckets”) for increasing L/D at various speeds. So this nice summary really resonated with me. Thanks again.
Once again you did an outstanding job gathering all this info and putting it all together so we can all understand and learn from these horrible accidents.
As a private pilot this was never mentioned to me and I was unaware that at minimal weight this could be a factor. I guess that's why they call it a license to learn. Great video.
It's troubling that your training did not cover this. If you got your license in the US, please re-read chapter 5 of the PHAK (Aerodynamics of Flight), specifically the section on "Load Factors", which includes everything mentioned in this video, including the V-G diagram.
@@oisiaa The POH of the PA28 and C172 that I'm familiar with both publish a VA at multiple weights, showing a lower speed for lower weights. I have an extra step in my preflight planning that determines my VA based on my weight by interpolation. This is always my personal Vne
@@owisagrom I fly big jets where Va isn't really a thing. "Maneuver speed" speed for us is the speed at which we can fly a 30 degree turn with stall margin. We have a hard g limit, not Va.
Great class for all pilots. Usually, there is more than one link broken for an accident to happen, this may well be the case. Thanks Juan. Poor guy didn’t know what he was getting into. RIP.
The most eerie thing in my opinion is that the person filming definately noticed but filmed back to the couple as if it didn't happen. Like they didn't want the plane crash to ruin the day.
its a somewhat common response to some types of traumatic events. almost as if the brain just overwrites that portion of memory to avoid dealing with it. always creepy to see though. people dying and everyone just going about acting like its not happening
@@kekke2000 "he person filming definately noticed " The phone follows the plane past the point where the wing broke, but that does not mean the person holding the phone was looking at the phone or the plane.
Flying fighters, we use a version of the V/G diagram to show 2 important features of performance-corner velocity (smallest turn radius which happens to match Vm) and best turn rate airspeed (faster and G-limited). If you lay two competing [Em] diagrams on top of each other, you can find your maneuvering advantage. As always, fantastic video Juan.
It looks like the left wing bent backwards, causing a runaway pitch-up moment until it snapped off. That is, in the first frame where the wing flexes it looks like the wingtip flexes first, rather than at the root. You can even see the wing crease just outboard of the root.
I just can't relate to people who do stuff like this. I guess trying to do something cool and memorable trumps good sense. A flyby with a plane is cool and I've seen things like this done with skydivers and it makes no sense. It's cool if it all goes well but look at the penalty for failure!
It looks like they were still celebrating even though they literally watched the plane break up directly over head. Maybe they thought the wrong falling off was part of the show?
Aero Engineer here with a lot of ag design/testing/certification testing..... When you emergency drop, the effluent drops down entraining air which increases the angle of attack at the horizontal tail which increases the down force at the horizontal tail. This tends to pitch the aircraft nose up without any input from the pilot. A number of AT-802's have been lost because of this phenomenon, but in this case the horizontal tail stalls and the aircraft bunts (uncontrollable nose down).
I think you have the answer sir. After watching the video frame by frame it appears the tail got sucked down by the water down wash coupled with sudden wing unloading. Maneuvering speed has to do with full control deflection limits, as I recall from ground school.
wow I never thought about it, counter intuitive and scary.. of course I never had the option to dump all my passengers out the bottom of the aircraft and yes I have had my mother-in-law in the back before :)
Wouldn't have even thought that dropping something (heavy) from an aircraft would be legal, outside of some exceptions like agricultural or fire fighting activities. Far better to release colored smoke or something like colored confetti/chaff
It’s legal (in the US) as long as you make sure it won’t harm anything on the ground and you have landowner permission, etc But low altitude dropping over a crowd in the US would probably be a quick license pull
Right, was wondering why no one else had pointed this out! A guy plumetting to his death... Pan back to the choreographed reveal hug. Lost a little more faith in humanity...
THis has @@worldwideflyby prompted much reaction. BUT I highly doubt they really seen what we did in a post flight event w\video review...think about it PERSPECTIVE → point of view[actual] then also add in SPEED & flight altitude & then window of visual [time] before out of. SemperProrsum~Godspeed
If I follow (which I my not), by halving the planes mass and not changing it’s profile in the air, it’s accelearation from aerodynamic forces double - which if you’re pulling a 1-g nose up maneuver as you do that, you go from 1g to 2g of force on the fuselage. The wings may be fine taking those forces, but it’s going to maneuver more nimbly, and it’s going to mean 2g of force on the engine mounting in the nose.
@@Relkond thanks, thats what I needed to finally understand it. Reducing the weight suddenly doesn't change the lift the wings are creating, but it does increase the G's the airplane is pulling.
My thoughts as well. He is essentially dumping over a half ton of weight from the nose of the aircraft in less then 2-3 seconds. Seems like that would cause a CG shift, that maybe he tried to counter too much?
I'm leaning towards structural failure from either pass flights or an ongoing issue that was unnoticed. That plane should not have failed during a simple maneuver like that.
@@flyinbryanfpv even if it was perfectly centered on the cg of the airframe that much weigh loss in that time frame would cause it to at least "balloon" up a bit. Which the pilot might have tried to counter with forward stick. Which would have been bad idea. I am not saying I know any of these things to be fact, just stating my own point of view from the video provided. It could have been coupled with a problem airframe as well. Just a bad way to go and for no good reason.
@omegawolf81 I agree with you. The part I was addressing was the possibility of cg shift being the cause. Its more likely the sudden loss of 1000+lbs of water and pilot input causing the catastrophic failure
my CFI fully explained why VA reduces with weight. we did different manoeuvres with 2 people onboard a C152 ....and i learnt how VA reduced with one person. i placarded the airspeed indicator for VA with just me flying alone.
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I remember as a kid watching in Bishop Ca, a contract pilot showing off in a Turbine Aero Commander make a high speed run down the runway then pulling up hard. The mechanic the next day noticed fuel leaking out of the left wing. Measuring the wing tips, the left wing was 9 inches higher off the ground and the top of the wing was wrinkled. He was no longer a contract pilot.
The only Pilot that knew how to fly an Aero Commander with amazing feats was Bob Hoover. RIP. His plane now sits in the Smithsonian. What an awesome pilot.
@@dutchtubahe was definitely a smooth operator.
At Bishop i saw a Lear type private jet that was ruined when the pilots were screwing around came over the sierras crest and got caught up in the sierra wave(140 mph jet stream winds)--it bent the jet and they were able to emergency land at Bishop--i heard the jet was totaled
he had a future in the fast food industry
@@dethray1000LOL. Of all the things that never happened, this never happened the most. 😂
Many years ago ('94-'95), as a young A&P, we had a Pawnee with Hutch metal wings that were just full of cracks. We pulled the wings to repair them and found the fuselage wing attach points badly rusted internally. They looked great with nice paint on the outside, but just ugly inside with much material missing. It left on a truck to an aerospace welding facility for replacement. Scary stuff considering how they get yanked and banked in a highly corrosive environment.
Like old houses near the sea, paint layers is only thing holding them together. I think Popeye the sailor man had a song about that
@@shable1436 we had a water tank like that at work. you knew the metal had gone through when you saw the bubble in the paint. then we used to just drill it out and stick a nut and bolt in with a rubber washer.
the glory[& FAILS] always shines on the OPERATORS/pilots but, the MECHANICS and all that attached to support their mission[s] really is so important......maybe more so [idk4sure]
OPERATORS are the ones also in the line of weather a vehicle or equipment is safe too operate.
So it maybe would[have] passed PILOT pre-flight inspection but really it is a TEAM that creates the missions capability to be a success as in returning. The total success ends with safe return.
Thanks Juan,great report w\insights
Semper Prorsum ~ Godspeed
It's fineeeee
You save money by replacing maintenance with paint.
I had to rewatch the part about why maneuvering speed decreases with weight... I don't know if I'm the only one who got a little lost, but I could still use a deeper dive into the physics. I appreciated that you explained it multiple ways, but for some reason it's still not clicking for me. Thank you for diving into these tragic events so that we can all learn to be better and safer pilots.
If Juan is reading this I agree. I do not refute anything in the video, but clarification on the physics of why this happens would be good.
There is a detailed comment above this one that goes into how lower weight makes the airplane more nimble, and therefore able to apply more stress to the airframe. This feels right intuitively, but hearing it from a pilot would be cool.
Yeah I feel the same. The reason why it is not “clicking” is because he didn't explained it at all.
@@kingsizedmidget7294 I was doing some reading just now and while there's a lot of talk about critical angles of attack, weight, etc, I think distilling it down to the nature of flight helped me understand it better:
Flight is overcoming gravity. At straight and level flight, you are always pulling 1G. You are in balance with gravity because you are producing 1G of upward lift to counteract Earth's 1G of downward pull. When you start to climb, you pull more than 1G, because you're overcoming gravity. To generate 1G of lift in a heavy plane, you need a higher angle of attack from your wing than if you were lighter.
If you suddenly dump a lot of weight, your lift is going to go up at any given angle of attack (in the same way that taking off in a heavy plane will have a more sluggish climb, taking off in a light one will have a much faster climb).
So when a plane dumps a lot of water in the air while pulling some number of Gs, it will now generate more lift at that same angle of attack, which means more Gs. So what was a 4G maneuver becomes, say, a 6G or an 8G maneuver, then your wings rip off.
The way I heard it put is a heavy load will stall. A lighter load can generate more lift before the stall and thereby more stress on the frame. Think of the Va stall as a safety valve that dumps excess lift. The wings will eventually create the extra lift, but the frame can’t spread the lift. Even if the struts and spar distribute the force to the frame, now the engine mount is overstressed with its heavy load.
It’s because he’s looking at a case where the wing attachment failed, but then explains how the wing loading actually goes down. At 6:39 he briefly explains it’s not the wings that are overstressed by this issue, but the same wing loading applies higher Gs which can break other things. It’s just a bad example for the issue being explained.
Juan, let me add some details from my experience working as a aircraft structures certification engineer:
It is true that the maneuvering speed vA is defined by vS times the square rout of the design load factor. However, it is not a limit up to which the pilot cannot damage the airplane. vS is a calculated stalling speed (FAR/CS 23.335(c)), as estimated early in the design process. vA is a defined airspeed limitation to be used mainly for control surface and control system structural sizing. FAA AC 23-19A explains: "VA should not be interpreted as a speed that would permit the pilot unrestricted flight-control movement without exceeding airplane structural limits, nor should it be interpreted as a gust penetration speed."
The TCDS you present in this video is of a restricted category aircraft. Although limit maneuvering load factors seem not to be mentioned in this TCDS, in the restricted category certain limitations can be lowered below the FAR-/CS-23 minimum requirements, including limit load factors and structural safety margins. That is especially used for cropdusters to allow higher take off masses.
As far as wing structural loading is concerned: it does actually not change when you empty the hopper tank. Given, that speed and angle of attack stay the same. Why is that? The aerodynamic forces on the wing are unchanged as long as airspeed, angle of attack and it's configuration (flaps, ailerons) don't change. So the lift force doesn't change. The same lift force acting on a lighter fuselage lighter than before means the vertical acceleration increased, as Newton claims in his second law. To maintain level flight, i.e. maintain 1g, the pilot needs to reduce the angle of attack during release of the payload, as you explain.
It seems that the unlucky pilot in the video did the opposite and increased the angle of attack, leading to increased lift forces, which resulted in structural failure of the wing.
speed can safely max deflection of a control surface
I found this very informative, thank you. Would suggest pinning it
I was a structural tech for a while and completely agree with this comment.
Pilots need to stick to talking about flying. They also have a bad habit of blaming pilots only.
This is not the first time wings have failed in Mexico… Mexico is known for ignoring maintenance and inspections.
I’m fairly confident a properly maintained aircraft would have survived that. I see those duster fly really hard in the states all the time and no issues.
@@1KDave Did you just say 'pilots need to stick to talking about flying.'
Did I read that right?
If you go to 8:12 and change the setting to 0.25 playback speed, there's a moment right around 8:14 where you see the wing fold back diagonally. At least intuitively, it seems to me that this supports what you're saying. It's reminiscent of the silly game we'd play as kids, sticking our hand out of a high speed car and "surfing" - once the angle goes a tiny bit too high, the effect snowballs as the wing flips up and back.
I don’t know why this was recommended by the algorithm but you did a great job explaining and teaching. Thank you.
Probably for me is because I’m subscribed to a channel that does mini documentaries on plane crashes and I watched one of the videos last night.
I think the video title: "PA25-235 Sinaloa MX Gender Reveal Party Structural Failure" broke the algorithm.
Coming from a third generation ag pilot, great break down of this accident a lot of people misunderstand accidents in the ag world. Although mistakes were made, I am also leaning to the fact there was probably corrosion involved. Great job Juan keep up the good work.
Agreed. I’m imagining crumbling white spalling at the attachment.
Decades of hard work, likely living outside, previous over stress and possible neglect.
Condolences to the family(s).
Even with potential corrosion, it likely wouldn't have been an issue if the pilot hadn't pulled up so hard put so much load on the wings.
@@davidfrench5407he probably didn’t pull up. He just didn’t nose down while he was dumping. Most of the time you’d never pull the dump handle coming out of a dive and at high speed. You wouldn’t shed weight in an emergency under those circumstances in very many situations.
I started my ag flying career in an O-320 150 hp Pawnee before I moved to an O-470 Ag Wagon and later an O-520 Ag Wagon.
@@JoshJones-xd5mw from that angle he would have at least been conscious that he was heading toward a tree line. Tragic regardless of the exact cause, hopefully others can learn from this.
@@moretrash4you no, the nose came up. Did you watch the video? Juan explains it quite succinctly
Wow, what an educational video. That explains why there are several videos floating around the web showing structural failure AFTER dumping the load. Never made sense to me, but now I understand. I am a commercial pilot, helicopter, multi-engine, instrument rated, as well as A&P mechanic (all in the past, I am 80 years old). I was always keenly interested in areodynamics, and so am really grateful for your explanation of maneuvering speed dependence upon wing loading. As an A&P, I have performed the wing spar attach AD you talk about. I always liked the Pawnee 235, a very smooth and capable airplane, and a shame to see one lost. Thanks again.
While it is true that low weight does increase max Gs for the same control input at any given speed, the lift of the wings and so the couple at the wings roots is the same, so I don't see how low weight can be to blame for this kind of structural failure. Other parts of the airframe indeed are more stressed with more Gs, but not the wings because of this low weight situation. Thanks for your response, it meens a lot for us GA pilots your videos. Congrats.
Lightly loaded, the wings can produce more lift before stalling because it has more available angle of attack.
The way I heard it put is a heavy load will stall. A lighter load can generate more lift before the stall and thereby more stress on the frame. Think of the Va stall as a safety valve that dumps excess lift. The wings will eventually create the extra lift, but the frame can’t spread the lift. Even if the struts and spar distribute the force to the frame, now the engine mount is overstressed with its heavy load.
I had seen personally three of that aircraft in the early 70's where the tubing next to the tail wheel was corroding apart from the chemicals, speaking of such, why would anyone, especially pregnant, want pesticides and defoliant tank water to be dropped on them???
Anyone who wants this kind of nonsense for a 'gender reveal' probably has a IQ so low that they struggle with any concept above 'Whoo pink pretty stuff'
I thought the same thing.
Probably cartel members... not exactly geniuses.
Mexicans dont care we should let all if them into our country NOT
Thanks! There are numerous Airworthiness Directives on the struts, the one you showed for the main spar attachment and another for the aft spar attach. It does not look like either of those failed. As you mentioned, it does appear that the left wing failed at the outboard strut attach point. I’ve not done crop dusting with these birds, but I do have over 600hrs in Pawnees on glider tow duty. We are about 1200# below MaxGW. You are hard pressed to get over 120mph in a dive without that extra weight.
I used to fly the Pawnee (later the Canso) spraying in Africa, in the 70s. It is now a nostalgic chapter of my life and I found this video both illuminating and sad. Thanks Juan, you ALWAYS produce such high value information. Pilots would do well to follow EVERY ONE of your videos. Thank you.
As I recall… during the low level skip-bombing assault on the Ruhr Valley Dams during WWII, 5 of the 8 attempts resulted in loss of aircraft to both defensive gunnery and catastrophic structural failures.
One of my favorite movies as a kid was "The Dam Busters".
I have a small 2x2” piece of “AJE” , a Lancaster lost on the dambusters mission, AKA “operation chastise” … flown by Flt. Lt. Norman Barlow and his crew, lost to ground fire at 23:50 hrs May 16-17 1943… Godspeed boys…..
Nice reference!
Only one aircraft was lost over the dams, that happened at the Mohne dam. It pulled up but one wing was on fire and it broke up and crashed. The Eeder dam did not have defences. The aircraft that had to attack that dam all pulled up very steeply but none broke up.
@@chriss.4147 He could be talking about training / testing too. There's film of a least one where the bomb bounced into the tail and the aircraft went straight into the sea.
If you look at the still photo at 10:32 it looks like the left wing is folding up a few feet outside of the attaching point and not at the fuselage
Superb analytics so clearly explained
Thanks so much
Chris
Cambridge UK
Thank you for covering this tragic loss. You have given me a good understanding of what went wrong
I have always loved aircraft but I am not a pilot. This is an excellent reminder to me why I should never try to fly. The details that must be remembered around the weight, G-force, stall speed, etc... are not my strong suit. Would love to be a mechanic again, but you guys that are (good) pilots get all my respect.
I fly SEATs and I can tell you that the airplane does pitch up when the load comes off. If you ever watch a cockpit view you’ll see the pilot push the stick forward (full forward for a salvo). I think the pilot wasn’t ready for the pitch up, was well above ideal drop speed, and the rapid increase in G’s caused structural failure. Keep in mind that the wings are producing around 2900lbs of lift at that airspeed and pitch angle. When the plane loses, let’s say 1000lbs within a few seconds the excess lift causes the plane to pitch up rapidly. If you aren’t ready to counter that with forward stick, you will find yourself behind the plane. This tendency only increases with speed.
Juan, extremely well done. Thank you for the effort into the clarity and detail.
As to the manuevering speed- weight relation - you can think about the ratio of your stall AoA and level flight AoA as the approximate max gload physically possible at given speed. To keep it below the airframe max gload, you want to keep a given minimum AoA in level flight, regardless of weight. To do that, you need to limit your speed, and that limit is higher when you are heavier.
How do they know their child's gender? That usually isn't decided until years or decades after the baby is born.
If the hopper is forward of CG as it appears to be, isn't it possible the plane abruptly pitched up in response to the much lighter nose of the plane? The pilot may not have had training or ever practiced an emergency dump and would not have known to pitch hard down while dumping.
I remember a story my old C.O. told me, he was a young Buccaneer pilot on a squadron learning how to do toss bombing, only the airspeed indicator was not correctly calibrated and showing 20kts slower. Long and the short of it, coming in hot and releasing 2 1000lb iron bombs there was a slightly louder than normal thump and jolt only for his navigator to point out various bits of the aircraft where falling off as they where over g'ing the aircraft. 550kts, 200ft with what was supposed to be a 3g pull up.
Maybe another less counter-intuitive way to look at this is that for a given fixed wing load in this scenario, the rate at which the pitch changes will increase as the weight decreases. Classic F=ma. Less weight results in greater acceleration. Initially the rate of pitch was probably ok, but as the water exited, the rate progressively increased until the thing just about went vertical at the end and ripped the wings off.
I can from the good instruction see the pilot exceeded some limit but I still suspect a problem wing fitting probably waiting for a long time to fail..
I’m about to find out the gender of my baby. I’m gonna use this thing called my my mouth and vocal chords to reveal the gender to my friends and family.
That's why I would do these maneuvers with a vintage Curtis P-40.. There is no maneuver you can do that would cause a structural failure.
It was very briefly mentioned, but can we also highlight the fact of how low his altitude was. From the video it shows his altitude was lower than the palm tree tops he crashed over. I believe this was a panicked pilot that pitched way too hard when he realized his mistake and simply overstressed the wings. It wasn't G-force that broke the wing. At that speed and very high angle of attack the wings were acting as an "air brake" at that point and simply broke off.
I believe the compression struts of the Pawnee don't help much. They have a big internal stiffening beam, but all the same I don't think the failure behaviour is the same when the failure mode is buckling instead of stretching, and effectively there is no or little yield phase where you merely bend things. Once the strut starts to buckle and bend off axis, and the load is still there, that's it that's all.
I'm struggling to make sense of this. The graph is for fully loaded performance, so let's say under these conditions it can handle 4 g's which produces 16k lb of wing load. When the aircraft is fully unloaded, it seems to no longer be appropriate to use the fully loaded graph anymore. You would need to check against the unloaded performance graph. However if you remade the graph for an unloaded aircraft, all of the points may change, so the 4 g's likely would no longer be the threshold. It might now take 8 g's to produce the same wing loading. So the theory of the video seems to be that the aircraft was at a safe point on the graph, and after unloading, the safe point on the loaded graph instantly represented a break point on the unloaded graph. The force is an aerodynamic force which is based on drag and lift, not mass. The force is based on geometry. When the mass is suddenly decreased, F=ma would say for a constant aerodynamic force, a sudden decrease in mass will be countered by an equal and opposite increase in acceleration. But again it does not seem to be appropriate to compare this new g value against the fully loaded chart.
What it looks like happened to me is that the sudden acceleration increase caused by dropping the mass caused the aircraft to nose up beyond the desired angle of attack of the pilot. This uncontrolled increase in angle of attack caused an absolute increase in wing load. So it's not that for a load of 16k lb, the drop in mass caused g's to shoot from 4 to 8g's at the constant wing load, but that the additional increase in aoa caused the 16k lb load to increase to 25k lb, and the 4g's shot up to 12 g's, something like that.
It's crazy how out of touch people are, they continue on partying after watching the plane fold and go down...... wow smh
I don’t get gender reveal parties. I really don’t. I would better understand if like one of the options was certain death. But all it really is blue for boy and pink for girl whoopee.
I had never even heard of it before this. A what? Smh
That seems completely counterintuitive that the lighter the load, the slower the maneuvering speed. I have zero experience with aviation, but that graph and your explanation were excellent. Thanks. And gender reveal parts are pure cancer. Why anyone wants to know the gender before the birth I don't understand. What does it matter. There are so few nice surprises in life why deprive yourself of one of the best. Most surprises are terrible news.
Excellent explanation about this accident. Thanks Juan!
I had no idea manuvering speed would decrease with lower weight. I honestly dont understand why. I can understand that manuvering speed would stay the same even when lightly loaded but I dont see how it could decrease.
Am i missing something?
Oh boy, Juan, this is so terrible. Thank you for another excellent report.
It seemslike ground attack pilots would encounter the same issues when dropping bombs, especially old dive bombers. Are they just massively stronger structures?
The easiest way to ‘stack the odds’ in your favor is by starting any drop run well below maneuvering speed, this way you give yourself plenty safe margin even for a poorly executed technique. This should have been a fun event which certainly didn’t require a ‘high speed’ pass to ‘prove a point’… just very sad and completely avoidable and unnecessary 🤦♀️
Not to be a homer, but G in VG diagram stands for gust, not G forces
I don't understand the physics of why the maneuvering speed goes down with lighter weight.
100 gallons of water at 8.3 lbs per gallon (with dye) is 1200 lbs? There was 300+ lbs of dye?!
Interesting & complex incident most of us aviators should learn from and understand. Having said this, the aircraft being outside the envelope of it’s maneuvering speed, is NOT what caused the structure of the wing to fail. Can anyone explain why?
NOBODY notices the plane just broke up and crashed? Didn't the big bang behind the tell them something?
That was crazy the camera just went back to the couple like nothing even happened
Fortunate no ground casualties. I suppose there will be a totally unbiased, thorough and factually based investigation ... in Sinaloa, MX.
Imagine how that family feels, they will never unsee this..
Worth noting the couple had no idea the plane just crashed, or just didn’t want to ruin the moment.
The wing transitioned from airfoil to air-brake in a few seconds. Analogous to suddenly doubling air mass density during a pitch maneuver, pitch rate will double. Or at least the force generated by the control surfaces responsible for the pitch moment will double. During the transient the structure may yield under the suddenly increased load. Well outside the safe flight envelope into an unstable regime tragically in this case.
I've been curious as I've been watching the incident over and over how much the pilot actually pulled back on the stick. Wouldn't dumping that much load that suddenly, and that far forward of the CG, coupled with not enough experience and that high a ground speed cause the same reaction in the plane?
Damn, plane folds up, crashes and camera turns back, they keep celebrating like nobody just died in front of them…. Hugging, cheering. That’s f***ed up.
One of the first things i did in Flight Simulator was pull too hard too fast and got a game over.
A phone call telling me your child’s gender would suffice!
Aside from everything else, dropping 1200lb of water over/onto a crowd of people is incredibly dangerous in and of itself. Water has significant mass and being hit with such a large volume of water at so great a speed, without giving the water sufficient time to disperse , could very well cause serious injury.
Excellent, thanks Juan.
PSA: Stop the gender reveals. This one was especially stupid. But anyone who hikes also knows how many forests and lakes are being ruined by mylar balloons and glitter that people just explode and leave. I can't tell you how many times I've been walking a lake trail and there's another mylar balloon and glitter contaminating an area the size of a sports field.
Babies don't have gender anyway but that's a whole dictionary argument. Babies have biological sex and people aren't comfortable in English because we use the same word for biological sex as for mating. So they say gender. But "my baby has boy gender" is like saying "my unborn fetus likes to grow a full beard and work on cars". It's nonsense.
So this whole thing is dumb and bad. The whole industry needs to stop. Party stores and catering companies are just making so much money. Meanwhile dozens die in fires, crashes...
Excellent video
They don't call it the chicken stick for nothing (emergency hopper release lever)
That was very interesting, safe manoeuvre speed being lower with a lighter airplane is rather counter intuitive
There are old pilots and there are bold pilots. But very few old bold pilots.
So why would the pilot pull so many G’s. Whether it be 4.4 or 3.8, or 3, or even just 2 G’s.
I began my ag flying career flying the Pawnee and I never flew with more than 100 gallons. Never filled the hopper with liquid but we used the large hopper for dry fertilizer. I was trained at Ayers Corp. in Albany Georgia, where they make the thrush aircraft. You had to do a demonstration flight to get certified FAR 137 and part of the flight was a emergency dump. You had to learn to push the stick forward hard to keep the aircraft level cause dumping that much weight the aircraft wanted to climb like all get out.
That will tend to keep you out of trouble.
The tank looks so far from the CoG, i’m curious now what the training manual looks like for an emergency drop.
I agree. Looks to me like a rapid change in CG pitched the nose up.@@PaleoWithFries
The Pawnee pitch trim system was simple but not comfortable. A large spring on one end of a lever in the back of the fuselage attaches to a cable that attaches to the stick just above the pivot point. Moving the trim handle aft pulls, through another cable, the spring lever to tighten the spring and provide pull on the stick. Forward on the trim handle will slacken the tension on the spring and allow the nose to go down. Taking off with 150 gallons, usually the load is less for DA, will require a strong pull on the stick which the trim spring will help with. Emergency dumping with full aft trim will result in a significant pitch up unless the pilot pushes forward on the stick. The dump gate in the bottom of the hopper, also used to release dry material through a slim crack, allows slow release of liquid material as well. Liquid goes to the pump on a spray rig through a hose. The pilot may have been startled by the rapid pitch up of a full dump lever travel, fully open gate, dump. Or he may have been going for a spectacular pitch up. Or both. I personally know of two practice emergency dump fatalities.
@@gomertube I understand your comment - but a Crop Duster doesn't dump his whole load in one shot, it's sprayed in a fine mist. Which means that he's not experiencing a massive change in wing loading and Center of Gravity displacement.
Retired ag pilot here. I started out in a Pawnee 260 C model. It would carry the 150 gallons, I doubt that the 235 version could. That being said, I didn’t notice you saying anything about the hopper being well forward of the CG. I’ve dumped many times. There’s always a violent pitch up if you’re not trimmed in advance for it. If he also pulled back at the same time, then that would certainly overstress the aircraft.
As previously mentioned, corrosion was probably involved.
One other thing. Water weighs 8.33 pounds per gallon. Assuming 150 gallons, that’s an additional almost 50 pounds.
Looking at the pitch up, it’s entirely possible that the sudden change in the moment arm at the release of the load caused it as well.
Yup.
@@bryanrackard9268 Elvis, you captain now?
Thanks I was wondering how the CG was affected.
I used to fly PBY water bombers and we called it “checking forward” as we dropped the load. With practice, you could time it just right, so you wouldn’t even feel the load being dropped.
My grandfather flew PBYs in WWII. I was about 10 when he passed away, I wish I could remember his stories. I remember one where they ended up damaging a wing dropping depth charges
I watched that maneuver from the ground as a firefighter in So. California. The large plane was almost vertical before it passed over a ridge, dump his phoscheck and dropped straight down the 3000 foot mountain. He missed the ridge by about 50 feet. Most of the pilots back in the 80's were ex-military guys.
@juliogonzo2718 gathering of the eagles web page has some stories. Major Jack Randolph Cram (USMC), was the personal pilot of Marine Gen. Roy Geiger's PBY-5A, the "Blue Goose." On 15 Oct 1942, he won the Navy Cross and permanent nickname " Mad Jack" in operations at Guadalcanal. There's a great story of Cram rigging that PBY with torpedoes and dive bombing Japanese ships. J R Cram was my grandfather's cousin. I met him when I was eleven years old in 1967. I believe he was working in DC at the time. He had a large great Dane named Ace that my sisters and I got to play with.❤
until the day you misjudge it.....and C-130 rips its wings off.
That’s really cool. Where did you fly? I would really like to know more about pby water bombers. The old Martin mars often flew over my home as a child.
These crop dusters are loaded to cover several fields before they need to be reloaded. The emergency dump is used if you have a in flight emergency and have to take weight off of the air frame for an emergency landing.
So the person filming the accident follows the plane up until the wing breaks and the plane disappears from line of sight then turns the camera back on the couple hugging and keeps it there like nothing ever happend? RIP to pilot.
I’m probably in the minority but I think that gender reveals are a stupid, look at me act. I remember a few years ago at least one of them started a forest fire that burned multiple houses to the ground. Why don’t people just wait until the child is born and announce its gender then?
I miss the good old days when the cigar ring had the blue or pink on it. A simpler time.
Yup. If you wanted to get fancy, you bought a pack of announcements at the Hallmark store and mailed them.
Or the pink and blue bubblegum cigars!
0:17 I love how whoever is operating the camera paid enough attention to the plane to stay with it as the wings fold, but then just pans back to the soon-to-be parents as if they didn't just see what we all saw. "Screw that guy... it's a girl!" 🤔🤨
It probably didn't even register in their mind what just happened. That plane was literally flying by. 100+ mph. They just swung the camera back behind them and then right back to the over-spending, braggadocios couple.
Aye, I suspect they didn’t process what was happening and just swung back to the couple on instinct.
I doubt very seriously that anyone was aware of the tragedy that just happened. I would love to see video of the next 5-10 minutes. My guess is that the mood changed drastically once reality sank in.
The first clue that the person making the vid has no idea what they’re doing is the vertically held phone. It goes downhill from there.
They were watch the video of it right when the wing bends there is a terrified high pitched scream followed by a glimpse of people running away towards it, people were absolutely aware of what happened the second it happened and the cameraman had a perfect view so put two and two together
This is a great analysis. Really sorry for the pilot and family. RIP. Corrosion will be a factor, no doubt. It's always somewhere isn't it.
Maybe, but the manoeuvre itself was pretty crazy too, I'm not an expert by any means but I would wonder how much of a difference that might make when the pilot put the plane under such forces in the first place. The wing might have snapped regardless of any wear and tear. If it is a factor, I'd expect it to be a footnote rather than anything that significantly contributed to this outcome.
These are old planes. It’s not unheard of to find cracks in the tube structure after decades of rough service
@IrishmanAC many Ag pilots pull off these maneuvers several times on a daily basis. I have witnessed iy many times here in Ohio. I feel this pilot miscalculated his load and attempted a maneuver he was used to. A miscalculated load, and a potentially structurally weakened aircraft lead to this.
@@BamaRailfan AD 95-12-01 addresses In-flight separation of wing from airplane.
@@pennhiker5117 yes, it does. Unfortunately there are those owner/pilots out there that think it'll be ok unless they get caught. Sad but true. It happens a lot in the private aviation field and really is scary.. that said, I don't mean to accuse the pilot in the video.
Gender reveal parties have long been over the top. Now it just seems like it's out of control.
They wanted to hire a stunt plane for their party. I don’t have an issue with that. At the end of the day the pilot needs to make the choices for safety of their aircraft. Blaming the couple for this is just silly.
Totally irrelevant to the poor technique of the pilot who made a tragic mistake and died.
Nice job, both of you. I didn't lay fault to the couple.
And they only have two colors!
Because people want to make a big deal and post it on social media. Narcissistic behavior while people die, houses burn, forests burn and people get maimed for these stupid stunts. Boy or girl who cares!!!
Juan with a PHD level lecture. No distractions no opinions no judgments, stayed on topic with serious attitude, as it deserves. Operating an aircraft or any other vehicle that may hurt or kill someone deserves to be taken with the most high responsibility.
I’m not a pilot, but I watch these for precisely that reason. These people have a responsibility to themselves, especially to their passengers, and to the rest of us on the ground to analyze these events and learn the lessons. Juan hosts an excellent channel.
Unlike that other TH-camr…. You know the one…. Named Dan…. Lol jk love them both!
@m.lozano9970 @Brotha00
Former railroad conductor here. I totally agree. When I was a railroad conductor, I took safety really seriously! The safety of my train crew and train passengers was my first concern.
I don't like seeing preventable accidents like this. If something like this happened on the railroad, there would definitely be a rulebook violation.
Someone would get fired. If you don't follow the rules and don't safely operate heavy equipment, things go wrong! That's why I followed the rulebook every trip, every time.
I decided to switch jobs from being a railroad conductor. It was enjoyable, but highly stressful. I'm glad I pulled the pin when I did. It takes a toll on a person. I wanted a slower pace of life. I'm now a farmhand on a 7 generation family farm in Oregon.
I have much respect for Juan and his factual reporting combined with real experience analysis.
It's really sad that this pilot lost his/her life during yet another stupid "baby gender reveal" party.
RIP pilot, and sincere condolences to your family and friends.
The title of the video almost made me skip it entirely. Then I saw it was Blancolirio. Oh! Not the crap I was expecting. Glad I caught on quickly. Great coverage from Juan as usual.
So the airplane crashes and people continue celebrating?
Yeah
Dumping the hopper causes an extreme nose up trim, it will take you by surprise if your not ready for it. A massive push on the stick is required during the dump. I am guessing he was a banner or glider tow pilot, not an ag pilot.
Not in a Fletcher - the hopper is right over the wing - relatively neutral compared to forward hopper planes like Pawnees and AgWagons when dumped
Thanks, that fits much better to what the accident video shows than Juan's explanation.
Reducing weight (e.g. by dumping cargo) while in a turn with a constant wing-loading will increase the g-force on the aircraft, which can cause structural failure. But in that case it wouldn't be the wings that fail, those are at a constant load as we said. What would fail are the "fixed weight components", i.e. the high gees would rip the engine off its mountings or so.
What happened in the accident video was that the aircraft pitched up massively as the hopper was dumped. As Juan explained, at lower air-speed that would have led to a stall instead of a structural failure, but I don't believe the pilot intended to put the aircraft into a stall so close to the ground. So an unexpected change in trim that caused the nose to pitch up is a more likely explanation.
@@DrAHorn The final picture in the video is stopped at exactly where the wing failed. You can clearly see it twisting as the attachment point failed. So the wing was fine. Just it decided to go one direction and the body another. With a poor couple of bolts left somewhere in the middle.
@@josephoberlander Well, O.K. it may technically not be the wing. But it's still part of the structure that is engineered to support the full force that the wings can carry.
@@DrAHorn True. It does look like it failed a bit earlier than it should have, but such are old machines. A little deformation, a loose bolt, a bit of rust and it could be still up to spec but just barely/needing replacement soon. It will get interesting to see what the reports say about the condition of it and the maintainence recrords.
It's amazing to me the lengths ppl will go to reveal a gender of a baby. Pilot killed, wild fire started and so on so on. Call or text your friends it a boy or girl. Ppl died because of this nonsense, enough all ready
Monkey see, monkey do... it's rampant.
And they didn't even see the aircraft breaking and crashing and just continue celebrating! 😡
Was looking for this comment.
Though it seems that one person actually did and ran towards the crash site.
I'm sure they didn't celebrate for much longer, after realizing the plane had crashed.
It was in the video, someone should have noticed. Or heard.
I could not believe that no one, or almost no one, noticed the airplane come apart and crash.
@@flightsimguides The cameraman noticed and didn't give a shit
This is again a sad story where pilots are pushed towards being a “flying circus” with a bad outcome. I will file this video for all my aerobatic, UPRT or instructor students, when I’m desperately try to explain a flight envelope. Thank you Juan for doing it for me! I like the visualisation with different colours. 👍🏻
They proberly often did flying g displays that was ptoberly their job what was this one sny different
They're the captains of their aircraft. No one is forcing anyone to do anything. If you're not comfortable with a request, don't do it. That simple.
Excellent video as usual!
As a sometimes-getting-paid-for-it aerodynamics by training Ph.D. I view this through the basic physics lens. The force on the wings is proportional to the AoA and square of the airspeed (hence the exponentially rising limit curve vs. air speed). For a given speed, at heavy weight when you pull back on the stick the airplane cannot increase it's angle of attack quickly due to the airframe/load inertia and thus the rise in force on the wings is slow. At low weight when you pull back on the stick the AoA can rapidly increase because of the lower inertia/weight and quickly get to the point of generating a huge amount of force that's trying to yank the rest of the plane upward. Ever put your hand out the car window like an airplane wing and tilt it upward a little too much too quickly and your hand snaps upwards. If your hand was made of lead it would snap upward far more slowly than your water-ish made hand. That and the heavy plane/hand was already at a higher angle of attack to counter the aircraft weight/hand weight to keep it in the air. Ever see a light paper/balsa wood airplane suddenly get too much lift it pitches up very quickly whereas a heavier paper airplane does not pitch up nearly as fast. Excellent video as usual.
Ok that makes sense. I was about to rewatch the video. I was also wondering if destructive oscillation could be a factor as the wing load drops quickly as the water is dumped then loaded quickly when the pilot pulled up?
Thank you for confirming the reason for the "low weight" limits on maneuvering speed.
This is the same reason why some friends who work as maintenance/defense contractors warn pilots to be extremely careful when flying aircraft on short ferry flights. Minimal fuel, no pax or cargo (or wing ordinance!) the jet will respond very differently than it normally does, and this is especially noticeable on takeoff as the jet will accelerate quickly, and overspeed the gear and flaps, etc. and a sudden pitch up, is at high risk of exceeding limits. Another risk for inexperienced pilots is scraping the tail on the runway.
So…as I understand it…Don’t treat an aircraft like some video game!
Or a high performance jet fighter!@@57Jimmy
Excellent explanation. Thank you, from one PhD (in an entirely different field) to another. I’m a student of aerodynamics as a hobby, especially low-speed aerodynamics for soaring and the use of negative flaps (“drag buckets”) for increasing L/D at various speeds. So this nice summary really resonated with me. Thanks again.
Once again you did an outstanding job gathering all this info and putting it all together so we can all understand and learn from these horrible accidents.
Yes indeed. Very upsetting for the family who presumably hired this guy.
I’m a chemistry guy with no aviation knowledge, but this was so easy to follow while still diving into the technical. Excellent
Grandma killed by shrapnel, massive wildfire and now a dead pilot. How about just saying "it's a boy".
I wonder how the child will feel about this when she grows up.
I'm sure the child will never know.
As a private pilot this was never mentioned to me and I was unaware that at minimal weight this could be a factor. I guess that's why they call it a license to learn. Great video.
It's troubling that your training did not cover this. If you got your license in the US, please re-read chapter 5 of the PHAK (Aerodynamics of Flight), specifically the section on "Load Factors", which includes everything mentioned in this video, including the V-G diagram.
@@owisagrom I'm a commercial, multi-engine pilot and I was never taught that Va changes with weight. I always assumed it was for the worst condition.
@@oisiaa The POH of the PA28 and C172 that I'm familiar with both publish a VA at multiple weights, showing a lower speed for lower weights. I have an extra step in my preflight planning that determines my VA based on my weight by interpolation. This is always my personal Vne
@@owisagrom I fly big jets where Va isn't really a thing. "Maneuver speed" speed for us is the speed at which we can fly a 30 degree turn with stall margin. We have a hard g limit, not Va.
There's a reason why no markings for Va are on the AI. It is directly affected by weight. @@oisiaa
Great class for all pilots. Usually, there is more than one link broken for an accident to happen, this may well be the case. Thanks Juan.
Poor guy didn’t know what he was getting into. RIP.
In the first clip it seems the party attendees didn't notice the crash...?
Sad indeed and well done Juan.
The most eerie thing in my opinion is that the person filming definately noticed but filmed back to the couple as if it didn't happen. Like they didn't want the plane crash to ruin the day.
@@TELE6220 definitively
its a somewhat common response to some types of traumatic events. almost as if the brain just overwrites that portion of memory to avoid dealing with it.
always creepy to see though. people dying and everyone just going about acting like its not happening
Like "Oh the plane just had a huge structural failure and the wings ripped off...it's a girl, yayayy!!" :/
@@kekke2000 "he person filming definately noticed "
The phone follows the plane past the point where the wing broke, but that does not mean the person holding the phone was looking at the phone or the plane.
Thank you for explaining this. The old C130 that lost both wings is an example as well.
Flying fighters, we use a version of the V/G diagram to show 2 important features of performance-corner velocity (smallest turn radius which happens to match Vm) and best turn rate airspeed (faster and G-limited). If you lay two competing [Em] diagrams on top of each other, you can find your maneuvering advantage. As always, fantastic video Juan.
It looks like the left wing bent backwards, causing a runaway pitch-up moment until it snapped off. That is, in the first frame where the wing flexes it looks like the wingtip flexes first, rather than at the root. You can even see the wing crease just outboard of the root.
@@michaelbigelow3255 Electrical engineer. I've never flown anything but a 172. Aircraft are mostly cool for the engineering 😄
A wing is the pitch axis , it cannot affect pitch .
Yes like a forward swept wing. I can see that. I just came across this tragic video btw.
If I had nickel for every gender reveal disaster…
and notice how the pilot plundering to his death was not enough stop the celebration.
You'd have about 15 cents
I wish I had a nickel for every flight disaster caused by poor flying and/or poor maintenance.
@@bradsanders407 keep counting.
That was crazy! Even the guy recording it!!@@DaveG-qd6ug
What a tragic event, that was supposed to be full of joy. My deepest sympathies go out to the family and friends of the pilot.
I just can't relate to people who do stuff like this. I guess trying to do something cool and memorable trumps good sense. A flyby with a plane is cool and I've seen things like this done with skydivers and it makes no sense. It's cool if it all goes well but look at the penalty for failure!
It looks like they were still celebrating even though they literally watched the plane break up directly over head. Maybe they thought the wrong falling off was part of the show?
@@Skank_and_Gutterboy Everything has to be on Facebook even the morning bowl movement.
Aero Engineer here with a lot of ag design/testing/certification testing..... When you emergency drop, the effluent drops down entraining air which increases the angle of attack at the horizontal tail which increases the down force at the horizontal tail. This tends to pitch the aircraft nose up without any input from the pilot. A number of AT-802's have been lost because of this phenomenon, but in this case the horizontal tail stalls and the aircraft bunts (uncontrollable nose down).
I think you have the answer sir. After watching the video frame by frame it appears the tail got sucked down by the water down wash coupled with sudden wing unloading. Maneuvering speed has to do with full control deflection limits, as I recall from ground school.
wow I never thought about it, counter intuitive and scary.. of course I never had the option to dump all my passengers out the bottom of the aircraft and yes I have had my mother-in-law in the back before :)
😆I know the content was not funny but your comment is. Very.
Wouldn't have even thought that dropping something (heavy) from an aircraft would be legal, outside of some exceptions like agricultural or fire fighting activities.
Far better to release colored smoke or something like colored confetti/chaff
Exactly!!! People don’t think, is everyone more idiotic by the day?
@@BrainWasherAttendent Yes.
It’s legal (in the US) as long as you make sure it won’t harm anything on the ground and you have landowner permission, etc
But low altitude dropping over a crowd in the US would probably be a quick license pull
@@BrainWasherAttendent Yes they are.
It's been done before. But narcissistic parents always want to one-up their reveal parties.
Dying fighting fires or some other practical function is bad enough, but dying for something so utterly ridiculous and pointless is even worse.
$$$
So dying is worse than dying.
Amazing how everyone saw the wings fold and the plane start spinning but didnt miss a beat with their task on the reveal or miss the shot.
Right, was wondering why no one else had pointed this out! A guy plumetting to his death... Pan back to the choreographed reveal hug. Lost a little more faith in humanity...
THis has @@worldwideflyby prompted much reaction. BUT I highly doubt they really seen what we did in a post flight event w\video review...think about it
PERSPECTIVE → point of view[actual] then also add in SPEED & flight altitude & then window of visual [time] before out of.
SemperProrsum~Godspeed
Your chart explains why I’m not an Engineer. All I knew was the weight changed and he stressed the plane’s limits. Thank you for the explanations.
I had a very similar response. I also realised yet again why I am not a pilot (though I am a keen armchair aviator).
Even that’s too much information for most of us.
If I follow (which I my not), by halving the planes mass and not changing it’s profile in the air, it’s accelearation from aerodynamic forces double - which if you’re pulling a 1-g nose up maneuver as you do that, you go from 1g to 2g of force on the fuselage. The wings may be fine taking those forces, but it’s going to maneuver more nimbly, and it’s going to mean 2g of force on the engine mounting in the nose.
@@Relkond thanks, thats what I needed to finally understand it.
Reducing the weight suddenly doesn't change the lift the wings are creating, but it does increase the G's the airplane is pulling.
@@Koi-Koi-Koiwasn’t paper. Was colored water. And the palms didn’t have anything to do with this.
I'm just wondering how much Ag spraying experience the pilot had... thinking not much.
No telling how many G's had been pulled on that aircraft during its life of dusting, particularly if the same Pilot had been flying it.
Really great breakdown, as soon as I saw the crash video a few days ago, I thought "I hope Juan makes a breakdown video on this crash".
Is it possible that this emergency dump imposes a transient dramatic shift in the center of mass too, that contributes to that large nose-up rotation?
My thoughts as well. He is essentially dumping over a half ton of weight from the nose of the aircraft in less then 2-3 seconds. Seems like that would cause a CG shift, that maybe he tried to counter too much?
I think the hopper is on the CG so shouldn't have a shift as it was dumped all at once
I'm leaning towards structural failure from either pass flights or an ongoing issue that was unnoticed. That plane should not have failed during a simple maneuver like that.
@@flyinbryanfpv even if it was perfectly centered on the cg of the airframe that much weigh loss in that time frame would cause it to at least "balloon" up a bit. Which the pilot might have tried to counter with forward stick. Which would have been bad idea. I am not saying I know any of these things to be fact, just stating my own point of view from the video provided. It could have been coupled with a problem airframe as well. Just a bad way to go and for no good reason.
@omegawolf81 I agree with you. The part I was addressing was the possibility of cg shift being the cause. Its more likely the sudden loss of 1000+lbs of water and pilot input causing the catastrophic failure
Suggestion - attach smoke canisters, approach with white smoke, switch to pink overhead, fly tomorrow.
Ride a motorcycle with training wheels.
my CFI fully explained why VA reduces with weight. we did different manoeuvres with 2 people onboard a C152 ....and i learnt how VA reduced with one person. i placarded the airspeed indicator for VA with just me flying alone.