How does the Boeing 737 Bleed-air system work?!
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Why are Jet-engines essential in order for humans to be able to breathe in Aircraft, once they are above a certain altitude? How does the bleed-air and AC system work on an aircraft and how is it operated?
These are some of the questions that will be offered in this Video. As always I would love to hear if you have more questions and what else you would like me to talk about. Send in your suggestion below or contact me inside the Mentour Aviation app!
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The red and green pillows are correctly oriented port and starboard.
That was something the viewers suggested :) we were very happy when they happened.
@@andraslibal It was his own idea as well since he had thought about that before anyone mentioned it.
lol. I didn't even notice that.
So stern would be us
@@fistsofsteel5 me too :)
Every time you say "as always" in a normal sentence I hear "I hope you're doing absolutely fantastic" in my head 🤣
Tassos Anastasopoulos The first time I watched a video, before I got used to his accent, I thought he was saying “As always, I will be doing absolutely fantastic.” Haha
I think I just struck gold here. This is more fun and understandable than reading books.
So glad you think so! Enjoy!
Couldn’t agree more. I’m learning so much from this man.
It is enjoyable and understandable. Nice presentation!
For a jet turbine mechanic in training, you can’t beat a textbook.
Dont forget that Books possess their own value.😉
@@kamakaziozzie3038this video is very general in nature and should be treated that way. If your studying how to fix these machines, stick to the text books. There are a couple of BOEING videos out there that are excellent for system description and operation
Ahh! This explains the KFC smell in the cabin whenever engines swallow a bird.
It doesn’t explain it though you’ve just roasted yourself and you don’t know it
@@WELLINGTON20 not about to review this entire episode, but Mentour has explained it thoroughly. Hence my comment. You definitely must have missed it. Remember, you really must light the charcoal first if you are going to roast anything.
@@WELLINGTON20 it does - mentour himself literally said this is why you get a KFC smell (in another video)
Q: How does the Boeing 737 Bleed-air system work?!
A: It bleeds air into the Boeing 737.
having studied ...air conditioning I like this episode. And when I landed with my last flight weeks ago and outside looked back to the plane (or at boarding) I saw this openings for the heat exchanger and thought "what is that? that's a cool question for Mentour" but forgot it then. Shortly later, today... here we go! 👍 And thank you for the effort for all this graphics and pictures, that was a lot!
That means TH-cam learns to read your thoughts now
They need to add humidifiers
@@technophant there is not enough water on board for humidifiers but we could use water and pee from the toilet 🤔 🙄 😑
@@shijudevarajan143 google has been doing this for years
@@mattesrocketyou are suggested to drink plenty of water while flying to combat the effects of dehydration
1:48
"And make it possible to breed inside of the Aircraft"
😂
Mile high club here we come! 🤪
Ahh, air starters. Using a turbine to spin another turbine which starts the actual engine turbine. I love aviation.
[img]Xzibit picture[/img]
And then using the other engine to build up bleed duct pressure to cross start the other engine.
AND THEN using engine motive flow fuel pressure to move fuel from the tanks to the engines without needing to use the fuel boost pumps
And then using said bleed air to keep us all alive at 35,000 feet.
And then, taking some air from that process, which is way to hot to pump into the cabin as heat, and cooling it down to a point where it is way to cold to use as AC. AND THEN adding more hot air to it to make it the right temperature.
All I care about is that the damn things have no leg room..
H B Ryanair AND leg room? Not possible!
I don't know why I find "the smell of burnt bird" so funny. :D
It is little known that pilots need to have a top-notch olfactory sensory system. It's one of the first things you learn in aviation school, just like sommeliers who are trained to smell cork taint in wines. You have to smell different burned things and identify which one is the burnt bird. Failure to identify which smell is the burnt bird results in immediate expulsion.
You mean it startles your appetite?!
@@yatorke1761 Well... No. 😁
I commend Boeing for its bleedless, all electric pressurization in the B787. If the bearing seals of the engines fail smoke from the engines enters the cabin. It’s carcinogenic and a neurotoxin. Happens a lot.
One interesting fact about pressurisation that I read about is that this process of pressurising and de pressurising the aircraft is what makes most of the structural stress on the aircraft, so a plane that flies many short flights per day will get much more wear and tear than a plane flying long haul flights with more hours but only one pre/de pressurisation processes
Sure but the aircraft are designed with that in mind. Some B737 do 5 or more sectors a day, which equates to many flight cycles over its life time
When I flew on a 737-200 as a child, the pain in my ears was excruciating.
It’s very complicated; but very well explained. Thank you for taking your time putting these videos together. RgY 👍💯
When you say burnt bird, I think of sunday lunch and the chicken in the oven, my missus is usually quite good at setting the oven timing
For what its worth the "dryness" at altitude is due to the _very_ low dew point of the air at 30,000 ft. Something like -40 degrees or so. If you take a wet napkin and hold it over the air vent at altitude, it will freeze quite rapidly since the air is so dry. The water separator in the air cycle machine is really only needed when you're closer to the ground and the dew point is high enough to condense inside the expansion section.
This video is a life saver! I'm gonna do my Aircraft General Knowledge ATPL exam next week and air conditioning was the one chapter i really struggled to understand. Until now. Thank you so much!
Thank you Mentour for the video, can you explain the effciency difference in the "old" bleed air system and the newer compressor driven air system? What level of fuel saving is between the two systems?
Thank you again and have a great day.
We breathe jet engine farts.
My thoughts exactly! XD
That's more like regurgitation, same as penguins feed their chicks with partially digested food :)
It's not really farts. Farst would be exhaust gases from turbine, which... you can't breathe at all. Not for long for sure.
@@Stasiek_Zabojca Jokes aren't usually scientifically accurate. 🙂
Gabe's Hacks 😂😂😂
Went on a plane for first time and because of you and your videos I felt better about going. Thanks for being the awesome pilot you are and making these videos:) Thank you
Me from a week ago: mentor ur a 737 pilot why is a 777 in ur intro
Mentor: takes away the 777 on the vertical stabilizer
Me now: it’s still a 777...
Actually I see it as a common airplane because @Mentor wants to unite aviation. You can notice that he more often talks about other airplanes, not only his favorite 737.
8:23 burnt bird. Last vid that talked about Bird Strike said "smells like KFC" :-P
What happens when the seal on the turbine shaft starts failing? Does everyone breath in atomized turbine oil? Is there a way to monitor air quality on board?
Yes. No.
That's possible with older engine types, like JT8 D for example.
Newer engines, like cfm56 in 737s were designed with bearing sumps sealed with multiple labyrinth seals, pressurized with air to keep lubricating oil inside. If any leak occurs, it will be drained from the sump overboard. Maint crew will notice increased oil consumption, nothing more.
It smells of old socks. If it occers the crew will shut off the bleed on the affected engine. They will then open the crossfeed valve and feed the packs from the other engine. But, yes, it is rare as the air in the compressor section is at a higher pressure than the bearing housings so tends to leak into the housing pushing any oil inwards.
@@bobrice3957cross feed is for fuel. Cross bleed is for air
I just have to say... that is one kickass thumbnail!
We used to call the ground ASUs (Air Start Units) "Huffers".
Hi mentour, can you please do a video comparing the A220 family and the 737 family and what impact the success of the A220 have on the 737 especially the smaller variants of the 737.
Not air conditioning, life support. Its amazing how we trust technology to keep us alive in near space and even more amazing how rarely it fails.
Near space? Not even close
@@joet603 so where does near space start? It's a term I just made up.I can't find any reference to it. Outer space is reguarded as 100km +.
Back in the 70's/80's it was popular to hand out candies during descent to help with ears popping. Question: Was air pressure manually controlled in those days? There seemed to be more abrupt changes in cabin air pressure. I don't even notice my ears popping in modern a/c. BTW, always great videos and massive amounts of interesting info.
I think it's a newer control system that takes external air pressure into account, instead of just having an extremely basic reactive control system for the outflow valve. It seems to me the older the plane the more abrupt the changes are as well. The automatic controls he describes follow a system of proportional ascent and descent when climbing and descending, whereas back then, they simply maintained a certain cabin altitude, descending rapidly with the descent once below 8000 ft, and ascending rapidly until 8000ft before it suddenly stops ascending.
I don't care about my own discomfort just anything to stop the babies crying.
737s and a319 320 seem pretty good. The old dc9 used to always cause me ear discomfort. Those are old planes so that's maybe why
I’m glad newer aircrafts are getting away from bleed air system, it is too dry and easily prone to fume events which can be lethal in the long term especially for pilots and flight crew
@Minella Mita How tough would it be to toss a few gallons of distilled water into the cabin?
@@davidwhite2011 I'd imagine they'd have enough water to humidify the air for the entirety of a flight.
The newer aircraft still have the same fundamental problem... outside air is super old and therefore carries very little moisture. When that air is subsequently warmed up the relative humidity is even lower. Doesn’t matter how the air got pressurized, it’s the source. Adding humidity would be possible by humidifier, but impractical weight to carry.
When it smells of goose it's Christmas! 😍
If it smells of goose you have lost o e engine. Lol.
Without having even opened this video the answer is No. The Cessna P-210 is a Cessna 210 Centurian which has been cabin pressurized. The airplane is powered by a turbocharged six-cylinder engine. It's capable of climbing up and into the 20K flight levels. They were first produced from early versions in 1978 (834 Built) and remodeled to a more sophisticated version around 1985-86 with a Riley Turbine P-210 (40 built). There are not too many of them around today but they were considered "pressurized" airplanes that could carry six people back in the day. They had propellers and retractable gear. They were very easy to fly airplanes.
It's weird. The larger Cessnas were easier to fly than the smaller Cessnas. The C-152 is easy to fly. The C-172 has a slow roll rate and is more "sluggish" and thus more difficult to handle. However, the Cessna C-182 Skylane is a beauty to fly with a much faster roll rate than the C-172 Skyhawk. Almost all of the other Cessnas are very easy to fly, but the C-172 Skyhawk has the least aileron response compared to all of the other single-engine Cessnas. I have a few hours in Cessnas, about four (4) thousand hours in Cessnas. This does not account for the other hours I have in Mooneys, Bonanzas, Pipers, and other types, even in Eurcoups. So I have a little experience in single-engine Cessnas.
What you were saying about being able to identify which engine was affected by bird strike depending upon where the smell was. Well, I'm reminded of the Kegworth air crash in 1989. The captain having been used to a previous model of 737 assumed that the problem was in the right-hand engine due to the smell in the cabin. In fact the left-hand engine had thrown a blade. I'd guess that there is better training now when pilots move from one model to another. Although MCAS ...
It was a shame the captain got the blame for that, rather than the useless instrumentation.
Everybody repeat after me three times: BURNED BIRD, BURNED BIRD, BURNED BIRD.
We sacrifice a bit of fuel in order to keep the PAX alive.... Thank you Boeing, thank you Ryan Air!!!!
The Cabin pressurized with exhaust gasses for the flight duration can not be a good thing ,
Can't be nice for the Pilots and Cabin Crews knowing that their work place is heated with exhaust fumes from the jet engines,or the Ground Crews breathing exhaust gasses for a good percentage of their shift ,
The upside the pay is good !
@@markf5437 I believe the bleed air is extracted from the engine before the burn chamber. You are just breathing the air that enters the turbofan but compressed, heated, and cooled.
The PACS keep the PAX alive!
@@tonyperez8683 It is air that has been through internals of a mechanical compression process of shafts turbines bearings etc operating @ +600c or above there will be fumes from the oil lubricating the bearings
Interesting. The interesting question though is do you try and keep passengers warm to make them sleepy, or cold to keep them alert, or a mixture of cold and warm or take off, flight and landing :-)
Depends on airline and crew culture
10:08 yeah thats why everyone is breathing fart at the back end of a long haul flight, first class or not😂
Pressurized cabin with talkative passengers and screaming kids or built in oxygen bar through a mask? Uh I’ll have the oxygen mask please!
One plane I boarded had smelly jet fuel fumes in the cabin until they started something up.
The smell is from the Ramp
@@gnranger but from inside the cabin????
Aren't some of the newer planes designed to fly at lower cabin altitude levels somewhere in the neighborhood of 5000 to 6000ft?
Yes, the B787 is designed to have a cabin altitude of 6000ft
Q: How does the Boeing 737 Bleed-air system work?!
A: It bleeds air into the Boeing 737.
I work for the company that makes the heating packs and precoolers for the Boeing 747. Im the person who has to repair them and ive had to remove many birds from the Ram Heat Exchanger, normally its only a few feathers a beak and bones that are left by the time it arrives with me to repair.
What if the heat exchanger and air conditioning fail? Will the hot bleed air be passed into the passenger cabin?
No hot bleed air will get into the cabin, there are shut off valves to regulate and isolate the bleed air.
@@e30mark thanks for clearing my doubt 👍
"Nice and survivable flight" :D
Hi Mentour, nice video ! Quick question: Would it be possible to re-moisture the cabin air ? Waking up during a long flight with your eyes, tongue and al completely dry is the worst feeling. thanks
If the aircraft is on ground,and the temperature is hot(like 30°C). How can the ram air cool the bleed air down to the comfort temperature(like 20°C),thanks~
5:32 he says that after it is cooled by the ram air, it then goes through a refrigeration system called an Air Cycle Machine
Aircraft cannot be effectively cooled on the ground, without an external source of air conditioning.
Hi, i will give you the long answer so that hopefully you will understand how a pack works, if not feel free to ask more questions - there is not such a thing as a futile question! * The bleed air entering the pack via a primary heat exchanger is routed through a compressor driven by the coaxial expansion turbine - mounted on the same shaft - and where it is compressed increasing the potential energy made available to the turbine and thus its cooling efficiency compensating for the adiabatic rise in temperature - for adiabatic we mean a change in temperature due to a variation in pressure, the more the pressure is increased the closer the molecules are squeezed together, the more they collide, the greater the energy they release under the shape of heat, and viceversa- a secondary heat exchanger removing the heat from the compression process; a water extractor extracting the moisture from the air as it has been cooled down to its dew point - the amount of water vapor a gas can hold depends upon its temperature, the higher the temperature the more it can hold before becoming saturated, the lower the temperature the least it cab hold, the temperature at which a gas must be cooled down to to become saturated is referred to as dew point, at that specific temperature moisture forms - by the secondary heat exchanger; through the core of a re-heater into a condenser at the turbine outlet and preventing the formation of ice in the same condenser; back to the re-heater where it is heated to an optimal temperature, into the expansion turbine cooling it adiabatically to about 2C. The re-heater and the condenser are not part of the pack itself.
* The primary and the secondary heat exchangers basically consist of radiators using as cooling medium outside air entering the ram air duct via an inlet door operated by the onside controller in such a manner to maintain the compressor discharge temperature at 110C, and then exhausted overboard. The controller will drive the door fully open on the ground or during slow flight with the flaps extended triggering the RAM AIR DOOR OPEN light and fully closed as the airplane accelerates. The flow of air through the duct is also facilitated by the suction effect created by an impeller housed in the same ducts and driven by the coaxial compressor-expansion turbine assembly while deflector panels open on the ground to minimize risks of fod.
Hope it helps! Ciaoo
@@gordonrichardson2972the ACM cools the air. You must be a B747 man where the packs on that aircraft struggled to keep the cabin cool on the ground on a hot day. The B737 doesn’t struggle the same way
Why is the captain always sat on the left seat
It's the other way around in helicopters, though. I've always wondered why that is.
@mentour what is the point of drying out the air. Why take out all the moisture
2 days ago I ended up in that 737-900ER windowless 'window' seat. Thanks for letting me know why it exists
Do all pilots know as much as you do?? Such complex systems.
Yes, this forms part of the typerating of the aircraft
Yes and no. As he states this is part of the type rating for your aircraft. So he knows all this info about the 737. I don't fly the 737. I know...very little about this. We all know the systems of our specific aircraft (though his ability to teach it has more to do with his training captain position than the avg 737 pilot)
You perfectly describe why flight is so miserable for me... I am sensitive enough that I develop problems as low as 5,000 feet- when visiting family in the West I had to have my wife drive because crossing the Rockies was hell. So for me, cruising at an effective 8,000 feet is physically debilitating for hours at a time.
You are very intelligent am very proud of you Captain 😘😘😘
Hello Petter, why, during the startup of the engines (or at the beginning of the taxi phase) often a strong smell of jet fuel invades the cabin? Is this caused by the bleeding? Isn't the fuel injected valley of the compressor?
On low power settings while standing still jet engines tend to recirulate air. Meaning the air is pushed out at the back and some of that air is sucked back in at the front. Combined with some incomplete combustion during startup, you might smell jet fuel.
@@danielrose1392 Thanks Daniel! It makes sense!
So many times passengers pressing callbels and asking the crew why there is this smell. Sometimes they turn on bleed air too fast after startup :)
I was thinking of this same smell I experienced a while ago. Smells like burnt kerosene!
@@FRDRCE
It is burnt kerosene, that's basically what JetA fuel is.
Last 737 I was on had bad filtration. I smelled farts for 3 hours. 😟
Pressurized piston-engine planes usually get air from their turbochargers. I was just looking at a Cessna P210T that was in the shop who look after my plane. Nice plane, but the bill for the spar inspection was several times what my much-more-modest plane is worth.
Laura Halliday Interesting, I never thought about that!
The beeding air system can be dangerous when some poisonous motor oil gets in the air: passengers can be intoxicated! Why don't you mention this? It's one of the reasons why the bleeding air coming from the engines will be avoided by using separate air compressors
Very good. I think it would be interesting to cover the British Midland Flight 92 accident, wich is related with wrong assumptions about the bleeded air source.
10:55: I remember back in the 70s riding with my brother in his Datsun 510 sedan trying to get up to Paradise on Mount Rainier. That poor car was gasping half way up the ascent, lol!
THANKS VERY MUCH FOR ALL THE INFO!
What about WW2 fighter pilots; where did they get their oxygen from, when they were escorting B-17 bombers over Europe?
Craig Bathurst Unpressurised cockpit with oxygen cylinders.
@Mentour Pilot: Often when I'm sitting in last rows of a plane, I can smell burnt fuel when engines are started. When I get places in the front I never have that sensation. Could you tell me why this could happen? If feel that it is connected with the things you discussed in this video. Thanks!
At the beginning the APU starts to assist engine start thus smell. Or do you mean after takeoff when engines are already running and airbourne?
Hi Petter, very informative video as always thank you. I have two question: how do you pilots get around being left/right handed flying an Airbus w no yoke and is there any rule that you and other pilots find excessive our outright stupid? Thanks.
Thanks for all your videos. I'm a nervous flyer so learning more helps to make sense of everything that's going on. I think I've actually been converted to an aviation enthusiast (although the fear probably won't completely go away lol).
Why not pressurize to sea level, so there are no headaches or sinus problems? Also, why not give people more fresh air? I always feel sick after flying. Probably because I've been breathing stale air.
It's not pressureized to sea level because giving the fuselage the required strength would make it so heavy that it couldn't fly. The air quality is quite good. You're more likely to get sick from the tray table and surrounding areas than the air.
Do pilots need to practice with the oxygen masks on, so they can understand each other?
Maniac3020 the oxygen masks have microphones just like our headsets.
Yes we do practice. Once every year (US) we board an aircraft and go through a drill using the masks and smoke goggles. Some airlines do this in a simulator.
@@Valantir Oh, I see. The microphones cannot be wired up the camera, so the viewers can't hear it.
One day I flew in an unpressurised airplane (Beech 99) at 18, 000 ft. The bag of chips was really balooned up. Also we had oxygen with us. :) Also, some aircraft like the Emb-120, C-17, C-5 use Oxygen tanks and not generators.
Planes are outstanding. Absolutely fantastic.
My question is why not maintain ground-level cabin pressure throughout the whole flight? Maybe I'm just a big baby or maybe my ears are just extra sensitive to pressure but it seems like very time I have flown my ears hurt like hell.
The fuselage can't withstand the pressure. To make one strong enough to do so would make it so heavy that the plane couldn't fly.
Love your Port and Starboard pillows!
That method of diagnosing the bad engine led to an infamous crash in England. An engine was malfunctioning and they smelled smoke in the cabin. So the flight crew shut the engine down -- but the *WRONG* engine (the *GOOD* one). What happened? They were flying a newer submodel of an aircraft they were familiar with. One of the changes the manufacturer made was to switch the cabin air to a different engine. Crash investigators concluded that the crew weren't adequately trained on the newer plane! 😥
The 787 approach is better. When you make pressurization and climate control independent of bleed air from the engines, you can also do a better job of controlling the temperature and humidity.
Controlling the humidity requires a source of pure water. Such a system was proposed, but never implemented on the B787.
@@gordonrichardson2972as far as I am aware there are 3 humidifiers on the B787
Great video. Very insightful. Really appreciated the animations as well. 👏
so what happens if both engines set on fire? where does air come from?
Lancashirelad ty:)
doesn't matter as your plane falls out of the sky and you die. :) As mentioned the APU, he mentioned it at the start of the video, but didn't really go into it.
Why is it pressurised at around 8000ft and not much lower? Also why do they not put some of the water back to the cabin to make it less dry, is it an ‘all or nothing’ type system
Amy Wagstaff if they pressurise to 0ft that would be a huge amount of force exerting on the airframe and it would weaken much sooner. The pressure at 0ft pushing on the frame is more than 8000ft so it’s a fine balance. The 787 and A350 can pressurise to 6000ft I believe because the fuselage is made from composites instead of pure metal so it’s stronger and doesn’t bend and flex as easily. Therefore it can take more force
Mentour, you should do a video on all of the worst or out-dated systems on the 737-NG’s! Would love to know your opinion!
That thumbnail is absolutely horrifying.
Excellent presentation, very informative.
Glad you liked it!
If I paid for a window seat that turns out to not be there I would start digging one my self
No I am just joking ;-)
"It uploads air," haha!
Now I know why it smell like fuel burn and water.
7:45 Literally everybody coming from the news outlets: "Actually, MCAS is the worst system on the 737."
It’s only on the newer MAX versions with the larger engines that caused a change in handling dynamics, not the older 737’s that make up the majority of the aircraft in service.
@@mikegirard4388 That's the joke :)
The APU wasn't working on a flight? Are they allowed to fly with inoperative APU?
tisoy909 yes. It's quite common.
Petra, I recently watched a 60 Mins segment in which they discussed this very topic of the bleed air system. In this interview they talked with several pilots who are suffering from various illnesses that they claim are in direct connection to breathing this engine bleed air. From watching this I got the impression that this air is not tested and the filtration process is not nearly as effective as the airlines and manufacturers claim. Do you have any input? Have you seen this program? I am quite concerned about breathing this air and more importantly concerned for the flight crews.
Yes, that’s a different video
I have the feeling, that at this topic there is a lot of missunderstanding. My perception is the following: The air does not get polluted by the system directly, by the construction or the components themselves. The problem is the air all around the aircraft while standing at the gate: When it's standing there and the APU (Auxiliary power unit) at the tail is running it creates such a polluted air and when then the wind carries this directly into the cabin via open doors or the starting air conditioning then we get the very bad air inside, the same when the main engines starts and the plane is still standing, and the engines are running slowly and therefore the exhaust gases aren't yet blown so strong away but get blown by the wind (if it comes from behind) directly to the entrance of the engines where this exhaust gases are sucked in again and goes then in parts into the cabine... so it's just the bad exhaust air around the engines that gets sucked in again or simply comes in by the open doors, but it's not the construction itself getting the air from the engines compressors. I saw all this very often, when I was flying, even the last time: I had to enter the plane at the rear door, people jamming, I had to stop 1 step outside the rear door, the APU was running and strong wind blew the exhaust fume directly into my face (and into the open door into the cabin), I had to stop breathing, had the feeling breathing in directly the exhaust fume would be very bad, hardly couldn't breath. The bad thing: before me was a father with a baby. I had this once even more extrem because it was very stormy and both doors were open at boarding and the very strong wind somehow very directly brought all the exhaust fume from the APU into the cabin and the bad air was getting worse and worse inside and (I am also a bit sensitive) had the feeling I hardly couldn't breath anymore properly and bording went so slowly, so it was for long, and I thought why the hell don't you close one door, the rear door near the APU that the wind can't push in the air. That I might be right with my theory could be maybe proofed because all this bad air situations always stop after a couple of minutes after we are in the air, so then the wind can't push bad exhaust fume anymore through the doors or towards the entrance from the engines. For me it's a tragedy for the crews, that have to breath in every day this dirt. Why can't they start the APU later or at least leave the rear door closed when the wind is coming from behind, why not placing the plane always in that direction into the wind (at "open field standing places") that the wind is not coming from behind, is the health of people not worth this bit of complications that would come along with this methods? Would like very much to know form @Mentour Pilot if my technical suggestion is right.
@@MentourPilot Great. I look forward to that video. I am a Patreon customer of yours and support your channel. I find it easier to communicate with you on TH-cam as opposed to the app simply because my phone is old and doesnt support your app to well. None the less...thank you for all that you are doing for aviation.
I used to hear a lot of stories about air quality on aircraft pre and post smoking bans(allegedly better before) urban legend or fact?
I mean, in aircrafts air is constantly recirculated soooo... Mmmmight be kind true but at the same time it sounds absurd..... Oh and recently i took a flight from Turin to Messina in a 738 and in the lavatory there is indeed a ashtray..... Wtf
@@giovannimonchietto1863 I can't remember if it was Mentour, but the explanation was something akin to: There needs to be somewhere to safely extinguish smoking materials when someone breaks the rules.
It’s only partially recirculated - it comes in from the engines, through the cabin, and out through the pressurization control valves.
We`ve missed the doggies. :)
Thank you, very instructive and the way you explained it makes it easy to understand.
Do I need Mentour Pilot to learn how to fly a boeing 737 max?
No, you just need to say NO to this piece of crap.
@@hugolafhugolaf What ??
You mean say no to the 737 max? If he wants to, sit in one on the tarmac ;)
It is so nice to see you using footage from argentina in 2:22! SABE airport
take a shot every time mentor says cabin
Bad day
Brofights sorry to hear that man
Very informative, one of your best. Thank you.
You were talking in this video how you can detect which engine is hit by a bird by where the smell comes into the hull the first. But there are several crashes happened where the pilot shuts down the wrong engine. Also because they cannot see the engines from the cockpit. What i was always wondering is why there are no camera's pointed to critical aircraft parts like the wing edges, landing gear, engines and rudder. In case of a problem the cockpit crew can put the image on one of the screens?
cameras sound impractical, also they'd need deicing and what not, so in essence u're introducing more problems than u're solving
@@stewiegriffin9218 A Goprto type of cam in a shatterproof glass enclosure is likely not a big deal. To retrofit, yes. To implement in the design phase, no.
Some asian airliners already have external cameras so passengers can see above/under the plane. This makes sense to have cameras pointing at the wings/engines
Or the crew can just look out a window. If there's something abnormal, there's generally passengers that are also keen enough to alert the crew. But often with bird strikes, it's not visibly apparent which engine was stuck. So a camera isn't necessarily helpful anyhow.
Weight and the most important maintenance cost. Flight attendants and flight engineers can perform the same function a camera can.
Many years ago, I flew from San Francisco to Honolulu in an OLD L1011. We could smell kerosene in the cabin for the entire flight. There were no mishaps, but I wondered how well maintained the old Lockheed had been. Good video👍.
35 Years ago, our Thermodynamics Professor shows us, that a jet-engine breathe the air of a tennis court per second (6 to 700 kg/m³)! Nower days it's up to 1,2 tonns of air per second...
Thank you, for that very infiormative channel! Greetings from Germany !
Americans will use anything but the metric system.
Scary AOA on that graph lol. Interesting video thanks!
Why in some old aircrafts the cabins have a strong smells like diesel fuel specially before the takeoff?
When in a line waiting for takeoff you may be smelling exhaust from the plane(s) ahead of you or even behind you if there is a strong tailwind.
How come the plane is allowed to fly with APU not functional???????
It's not required and can be started by battery power. Unlike the main engines.
I knew that. When I first began flying I could always detect a very faint odor of jet exhaust. It was later on that i found out that the air we breathe is indeed bled off from the engine and it acquires that very faint odor.
Why is all the moisture removed from the air, instead of leaving some moisture so that the cabin air is not so dry?
If moisture remained in the air, it would freeze and form ice at the exit of the ACM
If both engines fail, can you use the APU to provide cabin pressurization?
Yes
If both engines fail, cabin pressure is the least of your concerns, since the aircraft will descend rather rapidly!
You mentioned several times that the engines need bleed air to start the engines. I'd love to see a video about why that is, plus any other technical information about how jet engines work. I know there are several videos out there that dryly explain it, but it's just so easy to understand things the way you explain them. Thanks for the great video.
Whoever does your graphics is very good. A+
Great video Mentour I enjoyed watching it, have a fantastic weekend my friend.