How does the Boeing 737 Bleed-air system work?!

[@robsteele2087]

The red and green pillows are correctly oriented port and starboard.

[@andraslibal]

That was something the viewers suggested :) we were very happy when they happened.

[@XouZ88]

@@andraslibal It was his own idea as well since he had thought about that before anyone mentioned it.

[@fistsofsteel5]

lol. I didn't even notice that.

[@ronakknikam]

So stern would be us

[@latware]

@@fistsofsteel5 me too :)

[@vivianisz761]

I think I just struck gold here. This is more fun and understandable than reading books.

[@MentourPilot]

So glad you think so! Enjoy!

[@royalewithchz]

Couldn’t agree more. I’m learning so much from this man.

[@kamakaziozzie3038]

It is enjoyable and understandable. Nice presentation! For a jet turbine mechanic in training, you can’t beat a textbook.

[@Ganosioskuprai]

Dont forget that Books possess their own value.😉

[@NicholasRiviera-Dr]

@@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

[@mysock351C]

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.

[@tassosanastasopoulos1206]

Every time you say "as always" in a normal sentence I hear "I hope you're doing absolutely fantastic" in my head 🤣

[@Volkswagenitalia.]

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

[@qlemens6273]

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!

[@PauloGaetathe_original]

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

[@NicholasRiviera-Dr]

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

[@mattesrocket]

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!

[@shijudevarajan143]

That means KZbin learns to read your thoughts now

[@technophant]

They need to add humidifiers

[@mattesrocket]

@@technophant there is not enough water on board for humidifiers but we could use water and pee from the toilet 🤔 🙄 😑

[@dalegawne5286]

@@shijudevarajan143 google has been doing this for years

[@NicholasRiviera-Dr]

@@mattesrocketyou are suggested to drink plenty of water while flying to combat the effects of dehydration

[@CNder77]

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

[@rogerhargreaves2272]

It’s very complicated; but very well explained. Thank you for taking your time putting these videos together. RgY 👍💯

[@MarioFischer22]

Your video in 19 minutes, has more easy explanation than 1 month of class with my teacher at uni. Thanks from Brazil!!

[@darkprose]

Planes are outstanding. Absolutely fantastic.

[@frilime1710]

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.

[@julianarroupe]

It is so nice to see you using footage from argentina in 2:22! SABE airport

[@mikebelanger4165]

We used to call the ground ASUs (Air Start Units) "Huffers".

[@muskiet8687]

Just a clarification on the working of the packs.. The air cycle machine that cools the bleed air consists of a compressor and turbine. After a first heat exchanger, the air goes through the compressor so the temperature is raised before going through a second heat exchanger. This makes this heat exchanger more efficient because there is a higher temperature difference. Then it goes through the turbine to cool it back down, run the compressor and a fan that draws outside air over the heat exchangers because when it is sitting at the gate they need air flow as well. At this point the temperature can be below freezing so some bleed air can be routed to bypass the air cycle machine to keep it above freezing and keep any water in the air from icing up the system. This cold air is kept at a stable temperature that way and the system regulates cabin temperature by allowing more or less uncooled bleed air to mix with the cold air.

[@st4rskream]

Do you work for Honeywell, Liebherr or Secan? You must work for one of them with such a good understanding of the whole system

[@muskiet8687]

@@st4rskream I'm an aviation maintenance technician (plane mechanic). I've worked on many different planes and systems.

[@st4rskream]

@@muskiet8687 Similar to me although i work only on the bleed air systems for the A320, B747, F7X and A380.

[@andrewpease3688]

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.

[@joet603]

Near space? Not even close

[@andrewpease3688]

@@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 +.

[@clintonmead]

Love the videos, but two questions on this one Mentour: 1. Why is the water removed from the air intentionally when this is a common complaint on aircraft. Why not keep a comfortable level (or at least more comfortable) level of humidity in the air by removing less water or none at all? 2. How can you smell a bird burning after a bird strike if the burn chamber is after the bleed chamber. If you're not smelling burning jet fuel usually why would you smell burning bird?

[@gordonrichardson2972]

Clinton Mead Water is only removed on departure from humid tropical airports.

[@ArmyofSeaturtles]

At altitude there is very little moisture up there, also dry air is good for preventing corrosion on the air frame, Bleed air is compressed air about 250C degrees at about 40 psi, when u compress air it heats up at that temp. U will easily roast that bird to bits

[@NicholasRiviera-Dr]

@@gordonrichardson2972how does the water separator know what airport you are at?

[@ACCPhil]

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 ...

[@dreddwailing6395]

It was a shame the captain got the blame for that, rather than the useless instrumentation.

[@MikeyMcBryan]

I just have to say... that is one kickass thumbnail!

[@FrederickOpado]

2 days ago I ended up in that 737-900ER windowless 'window' seat. Thanks for letting me know why it exists

[@e30mark]

I have the pleasure of repairing parts of the bleed air systems, great to see how you use it. 👍

[@raffleschan6885]

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).

[@LunarCavalier]

you have no idea how much this helped me, I'm going up for easa module 7 exam next month and this helped me a lot, thanks!

[@henriklmao]

1:48 "And make it possible to breed inside of the Aircraft" 😂

[@revenevan11]

Mile high club here we come! 🤪

[@beboboymann3823]

Your illustrations are always top notch and help your narrative immensely. Way to go!

[@deadfreightwest5956]

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!

[@flyingark173]

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.

[@billi996]

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

[@petersteitz200]

Some times your aircraft is sucking in exhaust from another aircraft in front of you. If the wind is just right, this may happen. Peter mentioned the packs (air cycle machines) keep the cabin pressurized but needed to mention that the outflow valve(s) in the rear bulkhead really control the pressurization. The functioning of the air cycle machine is a study in thermodynamics. It is a complete course by it's self. I never completely understood it.

[@NicholasRiviera-Dr]

You make some good points. This video is a very basic overview of not only the pneumatic system but also the air conditioning and pressurisation systems. The air cycle machine is a very interesting device, as is the rest of the pack

[@Uluc994]

If there’s only one source to prep for the cadet pilot interviews I would choose mentourpilot… Thank you so much Petter, you helped me immensely in the interviews

[@Quasihamster]

Q: How does the Boeing 737 Bleed-air system work?! A: It bleeds air into the Boeing 737.

[@novel9481]

have a good times sir greetings from Turkey This video will make me succesfull on my exam that is tomorrow

[@jbee1011]

Love your Port and Starboard pillows!

[@thaifoodtakeaway]

Great video, I love the technical ones where you explain the details to the questions that come to mind when I fly in a 737

[@ikechukuchukumah6288]

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.

[@Pilotmoradi]

The best video ever on aircraft pressurization and system knowledge ! Thank you

[@rdvgrd6]

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

[@davidwhite2011]

@Minella Mita How tough would it be to toss a few gallons of distilled water into the cabin?

[@HobkinBoi]

@@davidwhite2011 I'd imagine they'd have enough water to humidify the air for the entirety of a flight.

[@markg7963]

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.

[@CrazyPetez]

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👍.

[@rolandkronqvist1034]

I don't know why I find "the smell of burnt bird" so funny. :D

[@saxojon]

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.

[@yatorke1761]

You mean it startles your appetite?!

[@rolandkronqvist1034]

@@yatorke1761 Well... No. 😁

[@billbright1755]

Cap Eddy Rickenbacker use to have to come down from high altitude ( for his aircraft ) to try to warm up. Your cabin heater was a silk scarf, leather helmet and googles, flying togs. Open cockpit and engine noise and fumes at practically arms length. Those pioneer air men were as supermen with an incredible indomitable spirit. Medal of Honor and many conspicuous outstanding Valor Awards. 🇨🇭🇺🇸🇨🇭

[@privskorp.9865]

THANKS VERY MUCH FOR ALL THE INFO!

[@yvonnejacko5644]

I just started watching this guy. He's absolutely amazing 👏

[@arjunshah2451]

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!

[@gus9459]

We`ve missed the doggies. :) Thank you, very instructive and the way you explained it makes it easy to understand.

[@Jonathan-wc2dk]

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?

[@brentbeacham9691]

Yes. No.

[@maximbatov9947]

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.

[@bobrice3957]

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.

[@NicholasRiviera-Dr]

@@bobrice3957cross feed is for fuel. Cross bleed is for air

[@hardrockuniversity7283]

Whoever does your graphics is very good. A+

[@johnfitzpatrick2469]

Excellent presentation, very informative.

[@MentourPilot]

Glad you liked it!

[@Jota_I_Ce]

Nice you were in Argentina! been following your channel for last couple weeks, excellent work Peter!

[@pierre2105]

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

[@harmattan77]

best quality tutorial ever. thanks

[@scottwilson7849]

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.

[@alexphillips4325]

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.

[@SofaKingShit]

I don't care about my own discomfort just anything to stop the babies crying.

[@howebrad4601]

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

[@aortoiliac]

Very informative, one of your best. Thank you.

[@SsiolisP]

Ahh! This explains the KFC smell in the cabin whenever engines swallow a bird.

[@WELLINGTON20]

It doesn’t explain it though you’ve just roasted yourself and you don’t know it

[@SsiolisP]

@@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.

[@Kooooyooooy]

@@WELLINGTON20 it does - mentour himself literally said this is why you get a KFC smell (in another video)

[@ajg617]

Interesting video. Regarding smoking, I flew on props and jets in the '50s and '60s and don't recall being overwhelmed by smoke - the cabin seemed to clear pretty quickly and most smokers were in a lounge area. There were ashtrays in the arm rests even back on the DC6s I flew on but I rarely noticed anyone smoking near me. Not sure if the DC8 or 707 used bleed air for pressurization but believe they took in a bit more outside air as did the DC9. Aside from that, the number of 'fume' events related to the bleed air seals seems to be increasing - for some reason affecting certain airlines more than others.

[@marsgal42]

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.

[@gordonrichardson2972]

Laura Halliday Interesting, I never thought about that!

[@JOSEGONZALEZ-wx9fb]

Great video man. I am downloading the app because this is just fascinating.

[@HolyHeinz]

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 !

[@_entrxpy]

Americans will use anything but the metric system.

[@xxxxxxxxxx6903]

This video is very informative and well narrated! You should really do training and instructional videos for the aviation industry! 👍

[@carlosladen]

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.

[@tdgreenbay]

Great information that's why this and blancolirio channels are the best for aviation information

[@kevinconvocar488]

You are very intelligent am very proud of you Captain 😘😘😘

[@NicholasRiviera-Dr]

Not a bad video but I would like to clarify a few things, @2:13 that is not a B737. Apart from the engine and strut being wrong, the airstart truck would be parked on the right hand side of the aircraft because that is the side with the pneumatic ground air connection so #1 engine can be started first @2:53 nice animation - has a few problems, but that is not a B737 engine @4:45 “the packs are basically controlling the pressurisation” - the air conditioning packs force the air into the airplane pressure vessel and the cabin pressurisation system controls the rate that the air flows out of the cabin @5:38 that is a very simplified diagram of the pack @9:11 I think you will find that during flight the air from the equipment cooling system is used to heat up the sidewalls of the forward cargo compartment. Recirculation fans pull air in from the passenger cabin and supply it to the main distribution manifold. The right recirculation fan pulls in air from the collector shroud in the forward cargo compartment. Floor grills in the passenger compartment (at the bottom of the cabin side wall panels) permit airflow into the collector shroud. The left recirculation fan pulls in air from the distribution compartment. @9:50 my understanding of the recirculation system is that it supplies air for ventilation which decreases the use of air from the engine bleed system and therefore saves on fuel, ie: decreases fuel consumption. It’s not to reduce the strain on the packs, that’s just a side effect @11:50 only one Cabin Pressure Controller controls the outflow valve at any time. The other Cabin Pressure Controller is a backup. The active controller changes for every flight or when there is an autofail event. @12:31 would have been nice if you had explained about the pressure bump. During the takeoff phase, the system pressurises the cabin to 0.1 psid below field elevation. This prevents the uncomfortable pressure bump (momentary pressure increase) at airplane rotation. @17:17 CH 36 pneumatics probably has more defects than any other system on the aircraft

[@cruisemissle87]

When it smells of goose it's Christmas! 😍

[@bobrice3957]

If it smells of goose you have lost o e engine. Lol.

[@rekhachoudhury2723]

A very useful topic and learned a lot. Thank you, Captain Petter. You have explained very well.

[@garreth123]

@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!

[@sharoncassell9358]

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?

[@TheGibby3340]

The physics behind the operation of an air cycle machine (pack) are fascinating. Hot bleed air in...cool/cold air out. And all done without a refrigerant! Very clever manipulation of pressure and temperature with some heat exchangers along the way. Interesting piece...Cheers 👍

[@rishavnandi6697]

Just a bit more specific, Air cycle machine is one system inside the PACK. PACK(Pressurisation Air Conditioning Kit) is also responsible to recycle the stale air in a regulated airflow to maintain Pressurisation

[@NicholasRiviera-Dr]

@@rishavnandi6697I never knew what the acronym PACK stood for 😅 You are correct that the ACM is just one part of the PACK system. However, l’m not sure what you mean by it’s responsible to recycle the stale air?

[@bierce716]

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.

[@victorwong3311]

Thank you; I always wondered why ear pops when changing altitude above 10,000 feet if cabin was pressurized

[@kanthikiiran]

What if the heat exchanger and air conditioning fail? Will the hot bleed air be passed into the passenger cabin?

[@e30mark]

No hot bleed air will get into the cabin, there are shut off valves to regulate and isolate the bleed air.

[@kanthikiiran]

@@e30mark thanks for clearing my doubt 👍

[@barneygoogle2720]

Very interesting video. Clear explanation of bleed air system

[@Howrider65]

All I care about is that the damn things have no leg room..

[@annatamparow4917]

H B Ryanair AND leg room? Not possible!

[@JavaSQL]

Excellent appreciable content on bleed air, Petter. Much appreciated!

[@WilliamJones-Halibut-vq1fs]

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.

[@FirstnameLastname77777]

This was a well made video Question... Can you manually depressurise an aircraft during cruise Also do all these pressure valves add aerodynamic drag to the aircraft if so then how does it affect the aircrafts performance on things like fuel and speed

[@Petertronic]

When I flew on a 737-200 as a child, the pain in my ears was excruciating.

[@matthijsklomp]

Two questions: 1. Can planes communicate with ATC via the flight computer (and vice versa) or only via audio? 2. Why don’t airplanes have 3-point seatbelts?

[@uzaiyaro]

Ahh, air starters. Using a turbine to spin another turbine which starts the actual engine turbine. I love aviation.

[@hugolafhugolaf]

[img]Xzibit picture[/img]

[@EinkOLED]

And then using the other engine to build up bleed duct pressure to cross start the other engine.

[@JDJD-mw9rr]

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

[@stephenbarringtonleigh367]

And then using said bleed air to keep us all alive at 35,000 feet.

[@everydayfixer8446]

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.

[@abd.f5744]

Thank you for that effort u had spent, really it is very valuable video and very amazing informations about air system In aircraft.

[@plzbgaming]

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...

[@jaroslavsevcik3421]

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.

[@rommysoeli]

10:20 It's very noticeable for me when I had sinus infection, while other can equalize pressure differential in their ear without any thought, I had deliberately force myself to yawn. The landing part is the most painful part, I have to see barometer on my phone to see how much more suffering left I have to endure. at least when I see the barometric altitude at negative on final, I know it was the peak of the pain and once we've landed and the engine has spooled down the pain would be gone. 8000 ft is painful, idk about 40K feet, people who have sinus infection and severe cold would have probably lose their hearing.

[@LilYeshua]

One plane I boarded had smelly jet fuel fumes in the cabin until they started something up.

[@gnranger]

The smell is from the Ramp

[@LilYeshua]

@@gnranger but from inside the cabin????

[@ZimmMr]

@mentour. Thank you so much!! I don't know if you saw that I texted you on your app's forum (and on few other videos) to make a please make a video like this one, I super appreciate you releasing it this week ! 🙂🙂🙂🙂 Your the best! .

[@billi996]

Why is the captain always sat on the left seat

[@RazvanMaioru]

It's the other way around in helicopters, though. I've always wondered why that is.

[@FromtheWindowSeat]

Great video. Very insightful. Really appreciated the animations as well. 👏

[@AlessandroGenTLe]

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?

[@danielrose1392]

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.

[@AlessandroGenTLe]

@@danielrose1392 Thanks Daniel! It makes sense!

[@pawelpablo898]

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 :)

[@FRDRCE]

I was thinking of this same smell I experienced a while ago. Smells like burnt kerosene!

[@johno9507]

@@FRDRCE It is burnt kerosene, that's basically what JetA fuel is.

[@AayushGore-]

I like the fact he uses red green cushion like red green wing end strobe lights on a plane ! ✈️ ❤😂

[@JayStClair-mh5wv]

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.

[@MentourPilot]

Yes, that’s a different video

[@mattesrocket]

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.

[@JayStClair-mh5wv]

@@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 KZbin 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.

[@Hoekstes]

Scary AOA on that graph lol. Interesting video thanks!

[@HelloKittyFanMan.]

"It uploads air," haha!

[@williamjones4483]

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.

[@bobbob5570]

so what happens if both engines set on fire? where does air come from?

[@bobbob5570]

Lancashirelad ty:)

[@JimmyMon666]

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.

[@airfoxtrot2006]

Great video Mentour I enjoyed watching it, have a fantastic weekend my friend.

[@Palpatine001]

8:23 burnt bird. Last vid that talked about Bird Strike said "smells like KFC" :-P

[@sagar4manutd]

You are such a gem. Love your dog.

[@Inkling777]

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.

[@gordonrichardson2972]

Controlling the humidity requires a source of pure water. Such a system was proposed, but never implemented on the B787.

[@NicholasRiviera-Dr]

@@gordonrichardson2972as far as I am aware there are 3 humidifiers on the B787

[@AdhamNafea]

Another great video, loved the animation, Well done

[@FerrySwart]

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?

[@stewiegriffin9218]

cameras sound impractical, also they'd need deicing and what not, so in essence u're introducing more problems than u're solving

[@hugolafhugolaf]

@@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.

[@FRDRCE]

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

[@rickyhall7514]

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.

[@GaiusCaesarAugustusGermanicus.]

Weight and the most important maintenance cost. Flight attendants and flight engineers can perform the same function a camera can.

[@JoanManuelG25]

Thanks a million for these videos!

[@CaptainBobSim]

7:45 Literally everybody coming from the news outlets: "Actually, MCAS is the worst system on the 737."

[@mikegirard4388]

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.

[@CaptainBobSim]

@@mikegirard4388 That's the joke :)

[@RichieRouge206]

Fascinating video! I didn’t realise it was before the burn stage which makes sense! Thank you for your brilliant explanation of how it all works

[@MentourPilot]

Glad you liked it!