4 ms·

After V1, the accelerate-stop distance, the pilot is committed to continue flying. The cargo area of most airliners is not pressurized, so the gash is not an i

After V1, the accelerate-stop distance, the pilot is committed to continue flying. The cargo area of most airliners is not pressurized, so the gash is not an immediate problem. In a case like this, the pilots would want to climb to several thousand feet and evaluate the situation before landing. Looks like the pilot did a great job once it was realized the airplane was damaged of remaining calm and flying the airplane.

lavrov 8y ago
Not a pilot, and not trying to be an armchair pilot, but why would he have ascended all the way to 36000 feet? Isn't there a real risk of depressurization with hull damage?
- sandworm101 8y ago
  No. If there was a leak then it wouldnt pressurize properly on the way up. If it was holding pressure, it would probably keep doing so.
  - spectre256 8y ago
    It totally depends. A weakened structure can hold pressurization for a while, and then suddenly (and possibly catastrophically) fail. A famous example of this is American Airlines flight 96 (1972): https://en.wikipedia.org/wiki/American_Airlines_Flight_96 https://en.wikipedia.org/wiki/American_Airlines_Flight_96
    - jedmeyers 8y ago
      Also Japan Airlines Flight 123
  - Johnny555 8y ago
    I'd rather not trust my life to "probably". If there was some damage to the hull or a cargo door that could lead to failure, it's under more stress and is more of a hazard as the altitude increases.
    - sandworm101 8y ago
      Less stress imho. At altitude the forces on wings/structure are far less than during takeoff.
      - Johnny555 8y ago
        The takeoff has already happened, and a landing (of some sort) will have to happen (which also means flying near ground level). The thing that doesn't need to happen is flying at full flight altitude when the pressure differential between the inside and outside is greatest.
      - TylerE 8y ago
        Incorrect. In level flight the wings have - by definition - 1g of upward load. Regardless of speed or altitude.
        nutcracker46 8y ago
        Consider cabin pressure differential versus the outside ambient air.
        FabHK 8y ago
        That’s what sand worm was saying - level flight puts less stress on the wings than takeoff (where you accelerate vertically, thus have more than 1g). Still, you don’t want to take a structurally damaged plane high up.
        sandworm101 8y ago
        1g in up/down force. But thicker air means more forwards/back forces. Higher engine power = more force, regardless of G.
        TylerE 8y ago
        Engine power is a fraction of weight. Even at full thrust (which is rarely used in commercial service, even for takeoff), the engines are only capable of 0.25g or so.
  - inferiorhuman 8y ago
    One minor UX gotcha: the alarm for a pressurization problem on a 737 is not all that intuitive. https://en.wikipedia.org/wiki/Helios_Airways_Flight_522 https://en.wikipedia.org/wiki/Helios_Airways_Flight_522
  - TheOtherHobbes 8y ago
    "probably"
  - FabHK 8y ago
    To take a structurally damaged plane to altitude with that argument (if it holds pressure, it probably won’t explode) is reckless folly.
- deleted 8y ago
  [deleted]
voodooranger 8y ago
the cargo hold of a 737 is indeed pressurized https://aviation.stackexchange.com/questions/8252/are-cargo-holds-pressurised-these-days https://aviation.stackexchange.com/questions/8252/are-cargo-...
- deleted 8y ago
  [deleted]
14 8y ago
@ codeisawesome If he only had a small drink he might have though a couple hours flight time is all his body needed to metabolise the alcohol to where it wouldn't be detected. Again I hate to speculate here and hope that there is a more rational explanation as to why things went the way they did. For example like captain_perl said at a certain speed the pilot is commited to take off. Ok, but why continue flying and not get enough height to turn around and land immediately? Was he following some protocol that states continue climbing then assess damage? Did air traffic tell him to proceed as planned? To the casual observer here, things don't add up. I am hoping there is some explanation but at this point something weird seems to have happened or we are missing a part of the picture. Very interesting.
- comex 8y ago
  You replied to the wrong comment.
sandworm101 8y ago
Cargo is definitely pressurized. Not heated/aced, but pressurezed the same as the rest of the cabin. Everying from the skin inwards is under 5000ish feet of pressure.
- Johnny555 8y ago
  It's heated above freezing too as far as I know, I've never had anything in my luggage freeze.
  - sandworm101 8y ago
    Heated in that the air becomes warmer as it is compressed. But not the additionally-heated air provided the main cabin. Even so, at low air density even -30 would take a while to cool the large mass of bags.
- selectodude 8y ago
  The front cargo hold is heated with engine bleed air.
sokoloff 8y ago
V1 is the takeoff decision speed, not the accelerate-stop distance. The accelerate stop distance is the distance it takes to accelerate to V1, reject the takeoff, and stop the aircraft. V1 is in KIAS (knots of indicated airspeed). ASD is in feet/meters. You are correct that passing V1, the aircraft is committed to fly unless an emergency relating to controllability surfaces.
jimktrains2 8y ago
> After V1, the accelerate-stop distance, the pilot is committed to continue flying. I'm not a pilot, but I'm 100% sure V1 means you can't safely abort the takeoff, _not_ that you're committed to the remainder of the flight. Also, the ILS is at the end of the runway, they were surely airborne by this point (i.e. past V2), so I'm not sure why you even brought up V1 in this discussion. In fact, I can't imagine being so low at the end of the runway. At somewhere like Midway (MDW), you'd almost certainly hit a house, at the very very least the perimeter fence. > In a case like this, the pilots would want to climb to several thousand feet and evaluate the situation before landing. I'm fairly certain that in an emergency situation you don't "evaluate the situation". Short of actually being unable to fly, you have to take off after V1. If there is any issue whatsoever, you alert the tower and begin to come around to do an emergency landing using "normal" emergency procedures.

lavrov 8y ago

Not a pilot, and not trying to be an armchair pilot, but why would he have ascended all the way to 36000 feet? Isn't there a real risk of depressurization with hull damage?

sandworm101 8y ago
No. If there was a leak then it wouldnt pressurize properly on the way up. If it was holding pressure, it would probably keep doing so.
- spectre256 8y ago
  It totally depends. A weakened structure can hold pressurization for a while, and then suddenly (and possibly catastrophically) fail. A famous example of this is American Airlines flight 96 (1972): https://en.wikipedia.org/wiki/American_Airlines_Flight_96 https://en.wikipedia.org/wiki/American_Airlines_Flight_96
  - jedmeyers 8y ago
    Also Japan Airlines Flight 123
- Johnny555 8y ago
  I'd rather not trust my life to "probably". If there was some damage to the hull or a cargo door that could lead to failure, it's under more stress and is more of a hazard as the altitude increases.
  - sandworm101 8y ago
    Less stress imho. At altitude the forces on wings/structure are far less than during takeoff.
    - Johnny555 8y ago
      The takeoff has already happened, and a landing (of some sort) will have to happen (which also means flying near ground level). The thing that doesn't need to happen is flying at full flight altitude when the pressure differential between the inside and outside is greatest.
    - TylerE 8y ago
      Incorrect. In level flight the wings have - by definition - 1g of upward load. Regardless of speed or altitude.
      - nutcracker46 8y ago
        Consider cabin pressure differential versus the outside ambient air.
      - FabHK 8y ago
        That’s what sand worm was saying - level flight puts less stress on the wings than takeoff (where you accelerate vertically, thus have more than 1g). Still, you don’t want to take a structurally damaged plane high up.
      - sandworm101 8y ago
        1g in up/down force. But thicker air means more forwards/back forces. Higher engine power = more force, regardless of G.
        TylerE 8y ago
        Engine power is a fraction of weight. Even at full thrust (which is rarely used in commercial service, even for takeoff), the engines are only capable of 0.25g or so.
- inferiorhuman 8y ago
  One minor UX gotcha: the alarm for a pressurization problem on a 737 is not all that intuitive. https://en.wikipedia.org/wiki/Helios_Airways_Flight_522 https://en.wikipedia.org/wiki/Helios_Airways_Flight_522
- TheOtherHobbes 8y ago
  "probably"
- FabHK 8y ago
  To take a structurally damaged plane to altitude with that argument (if it holds pressure, it probably won’t explode) is reckless folly.
deleted 8y ago
[deleted]

voodooranger 8y ago

the cargo hold of a 737 is indeed pressurized https://aviation.stackexchange.com/questions/8252/are-cargo-holds-pressurised-these-days https://aviation.stackexchange.com/questions/8252/are-cargo-...

deleted 8y ago
[deleted]

14 8y ago

@ codeisawesome If he only had a small drink he might have though a couple hours flight time is all his body needed to metabolise the alcohol to where it wouldn't be detected. Again I hate to speculate here and hope that there is a more rational explanation as to why things went the way they did. For example like captain_perl said at a certain speed the pilot is commited to take off. Ok, but why continue flying and not get enough height to turn around and land immediately? Was he following some protocol that states continue climbing then assess damage? Did air traffic tell him to proceed as planned? To the casual observer here, things don't add up. I am hoping there is some explanation but at this point something weird seems to have happened or we are missing a part of the picture. Very interesting.

comex 8y ago
You replied to the wrong comment.

sandworm101 8y ago

Cargo is definitely pressurized. Not heated/aced, but pressurezed the same as the rest of the cabin. Everying from the skin inwards is under 5000ish feet of pressure.

Johnny555 8y ago
It's heated above freezing too as far as I know, I've never had anything in my luggage freeze.
- sandworm101 8y ago
  Heated in that the air becomes warmer as it is compressed. But not the additionally-heated air provided the main cabin. Even so, at low air density even -30 would take a while to cool the large mass of bags.
selectodude 8y ago
The front cargo hold is heated with engine bleed air.

sokoloff 8y ago

V1 is the takeoff decision speed, not the accelerate-stop distance. The accelerate stop distance is the distance it takes to accelerate to V1, reject the takeoff, and stop the aircraft. V1 is in KIAS (knots of indicated airspeed). ASD is in feet/meters. You are correct that passing V1, the aircraft is committed to fly unless an emergency relating to controllability surfaces.

jimktrains2 8y ago

> After V1, the accelerate-stop distance, the pilot is committed to continue flying. I'm not a pilot, but I'm 100% sure V1 means you can't safely abort the takeoff, _not_ that you're committed to the remainder of the flight. Also, the ILS is at the end of the runway, they were surely airborne by this point (i.e. past V2), so I'm not sure why you even brought up V1 in this discussion. In fact, I can't imagine being so low at the end of the runway. At somewhere like Midway (MDW), you'd almost certainly hit a house, at the very very least the perimeter fence. > In a case like this, the pilots would want to climb to several thousand feet and evaluate the situation before landing. I'm fairly certain that in an emergency situation you don't "evaluate the situation". Short of actually being unable to fly, you have to take off after V1. If there is any issue whatsoever, you alert the tower and begin to come around to do an emergency landing using "normal" emergency procedures.