Which people? Where have you read it?
Any jet jockeys know the steepest decent rate possible out of 20K? I would think that low enough to do something extreme and get away with it. It has to be done without an airspeed indicator because I think they lost the panel display.
There should be an analogue airspeed for backup. In our machine with the airbrake out we’d easily get 3000 foot per minute below 10,000’ and 5000 fpm above 10,000’. I have no idea what an MD11 could achieve though.
I expected the opposite. Is that a structural limit, engines to idle, everything deployed, cross controlled hail-Mary run or what the book says you can do in general?
The plane certainly could HAVE made it to a safe landing if the emergency had been recognized early enough. But “smoke in the cockpit” wasn’t interpreted to mean “we must land with all deliberate speed or we will all certainly die.”
It has occurred to me that many air disasters over the past 50 years could have been avoided if only the pilots knew of the seriousness. In some cases, pilots didn’t know the engine was torn off, or the wing, the cargo compartment or other areas were on fire.
In today’s world, it seems like a dozen tiny GoPro cameras at $300 each, placed at strategic locations, might provide the viewpoints needed. Smoke coming from the cargo area? Let’s see what the camera shows…OMG, we’re on fire!..
What do you mean by “the opposite”? Lower descent up high and higher down low or something?
The book doesn’t give any limitations for descent rate. Normally the descent is limited by the cabin, if you “catch the cabin” then the cabin pressure will be increasing at the same rate as ambient and the passengers will have ear problems. I know from experience in the simulator that we can get 6000 fpm in an emergency descent from 30,000 feet. That’s with engines at idle, maximum speed and air brake out, cross controlling would be unwise and unnecessary at those speeds. Below 8000’ we are limited to 250 knots IAS which reduces your descent capabilities a bit. I know from every day experience that at 250 knots, engines at idle and the air brake stowed we will get about 1500-1700 fpm rate of descent. The air brake will at least double that. If it was me and I could see an altimeter and air speed indicator, I’d be happy with max rate of descent until about 7 mile final and 2000’. I don’t fly an MD11 though, and I suspect it, along with other largish passenger jets, isn’t nearly as flexible as my little Avro RJ100.
It was my impression after watching the Air France crash investigation that getting close to the upper envelope meant you were limited to what could be done as far as radical changes without stalling it.
Ah ok. Well first, 20,000 feet is no where near high enough for those kind of effects to come in to play. Second, limitations like that are related to how much positive G you can achieve before you stall or get mach buffet. If all you want to do is descend quickly you will be reducing the power to idle, increasing speed to maximum mach or IAS depending on your height and then deploying your drag devices (air brake and/or spoilers.) Other than the rumble through the airframe from the drag devices it should be no more harsh than initiating a normal descent from the cruise.
It’s in this documentary that it’s described that an ATC controller missed an important transmission.
that’s the original atc recording.
The video then stated that 30 seconds after that important transmission, the cockpit was an inferno and ATC never heard from the flight again. Even if the controller had heard it, there wouldn’t have been a thing he could do at that point in that timeframe.
I enjoy watching Air Crash Investigation but they have to overdramatize everything to keep it interesting. In their report on BA38, they made a ridiculous heroic production of the pilot shifting from flaps 30 to flaps 25 to avoid crashing into a motorway or a tube station, and then the AAIB analysis later determined that it merely saved the plane from clipping a couple of lightweight antennae near the perimeter fencing.
Yes the controller missed the call but by then it was too late. The program doesn’t seem to blame the controller for this, just points out that it happened.
The program also goes on to say the investigators determined that even if they had gone to Halifax immediately, they would not have had enough time. Doesn’t that answer your OP?
Yes.
I read somewhere, many years ago, that the pilots were panicking and speaking Swiss German to ATC. I see that there is a YouTube recording of the ATC conversations out there, but since this one is kind of close to home, I don’t want to listen to it. Maybe they were just speaking with a thick Swiss German accent.
My family and I flew on this flight from NYC to Geneva when we moved to Switzerland a few months earlier that year.
They were actually very calm up until near the end when it became suddenly clear that the situation was a lot more serious than they first thought. They spoke in easily understandable, though accented, English the whole time except in one small bit where the first officer accidentally transmitted a comment over the radio that was intended to go over the intercom. Normally the intercom is “hot” so you don’t need to push a button to speak but when you have O2 masks on the breathing is very noisy and distracting (I’d hate to be Darth Vader) and so you turn the intercom off and just key the mic when you want to talk. Push the switch the wrong way and you’re talking to the world instead of the other pilot though.
The recordings aren’t bad to listen to. The ATC is fairly mundane until near the end and the cockpit voice recorders stopped recording about 6 minutes before the crash so there aren’t any horrible sounds or anything.
I know that reverse thrust cannot be used in flight (and for good reason, see for example Lauda Air Flight 004). But in a situation like this, would that be helpful?
My knowledge of thrust reversers is purely theoretical as the BAe146 doesn’t have them or need them. Using them in flight would certainly make you come down quickly though I’m not sure how the engine pylons would cope with the stresses at those speeds. It’s a moot point though because not only is using them in flight not permitted it is also not normally physically possible so you can’t even use them in a thinking-outside-the-box kind of way.
Yes. I did some more research on this (well, I skimmed a Wikipedia article), and while most airplanes can’t do it, it’s very impressive in the ones that can.
Actually they can be used on some aircraft in flight (DC-8’s come to mind). Not sure about trying it on a plane not designed for it though. I’m thinking back to the American Airlines crash of an Airbus where the PIC used the rudder to compensate for a wing vortex created by the plane in front of him. It tore the vertical tail plane OFF (a whole thread unto itself). And unless this was practiced in a simulator the pilots wouldn’t know what to expect. It may pitch the nose down at a ridiculous angle and create a bunting situation (if I’m using the term correctly). Basically it would radically take the center airframe out of the slipstream and create a massive G load in a non-linear fashion. Imagine breaching the outer shell allowing 400 knot air to feed a fire.