Germanwings Flight Carrying at Least 148 Crashes in Southern France

[Caliga]

He could have reprogrammed the autopilot to descend to 'x' feet.  You can also program the descent rate and the aircraft will hold that as well.  You can cancel that at any time and take control, but of course you can't do that while unconscious.

[Admiral Yi]

Why would he have reprogammed the autopilot to make a controlled descent into the Alps?

[grumbler]

Why would he have reprogammed the autopilot to make a controlled descent into the Alps?

Why wouldn't he have wanted to make a controlled descent if the plane had depressurized?

[grumbler]

He could have reprogrammed the autopilot to descend to 'x' feet.  You can also program the descent rate and the aircraft will hold that as well.  You can cancel that at any time and take control, but of course you can't do that while unconscious.

Handy general rule:  when Yi starts asking leading questions, respond with leading questions, not answers (which only encourage him to ask more leading questions).  Cuts out a lot of the headache, and has to potential to start a discussion.

[DGuller]

If the crew conked out from depressurization, why would the plane make a controlled descent for 8 minutes?

Did the pilot nudge the Controlled Descent lever when he passed out?

Modern Airbuses have a lot of "survival instincts" built in.  I don't know whether automatically descending to low altitude when detecting depressurization is one of those things, though, but it would make perfect sense to have it.

[dps]

16 students and two teachers from small town high  school...damn. 😕

Yeah, that's horrible.   There was a flight out of New York on the way to Paris (I think) that went down off of Long Island in the 80s or 90s and there was like an entire high school's French club + French teachers on that flight.

edit: TWA Flight 800.

Yeah, and that was also the set-up at the beginning of the first Final Destination movie, which caused some controversy at the time--a lot of people felt that mirroring the TWA Flight 800 crash so closely was in very poor taste. 

Wasn't TWA Flight 800 also the one that they never could figure out a cause for?

[Berkut]

If the crew conked out from depressurization, why would the plane make a controlled descent for 8 minutes?

Did the pilot nudge the Controlled Descent lever when he passed out?

Modern Airbuses have a lot of "survival instincts" built in.  I don't know whether automatically descending to low altitude when detecting depressurization is one of those things, though, but it would make perfect sense to have it.

That seems plausible in theory, but given how advanced they are, it seems unlikely that such a fail safe would not include something as basic as "Oh, btw, while descending in this critical situation, don't descend so low that you fly into the ground".

[DGuller]

That seems plausible in theory, but given how advanced they are, it seems unlikely that such a fail safe would not include something as basic as "Oh, btw, while descending in this critical situation, don't descend so low that you fly into the ground".

That is a good point.  Terrain avoidance would probably top even emergency descent on the list of survival priorities.  It wouldn't crash until it ran out of fuel.

[celedhring]

Two people from a small company I worked for died in the crash - I didn't know them personally, but it's still a bit of a shock.

[grumbler]

That seems plausible in theory, but given how advanced they are, it seems unlikely that such a fail safe would not include something as basic as "Oh, btw, while descending in this critical situation, don't descend so low that you fly into the ground".

There is a difference between "don't fly so low you hit the ground" and "I'm so smart I can see that mountain right in front of us."  I don't think there is any such thing as an autopilot that can see ahead of the plane.

[Berkut]

That seems plausible in theory, but given how advanced they are, it seems unlikely that such a fail safe would not include something as basic as "Oh, btw, while descending in this critical situation, don't descend so low that you fly into the ground".

There is a difference between "don't fly so low you hit the ground" and "I'm so smart I can see that mountain right in front of us."  I don't think there is any such thing as an autopilot that can see ahead of the plane.

I dunno, gps and terrain mapping and radar ground avoidance and all that?

You could certainly be correct that perhaps the fail safe isn't sophisticated enough to account for that, but I would be a little surprised if it wasn't on these modern planes. The dang things can land themselves, right? Terrain avoidance (and this is gross terrain avoidance, not nap of the earth type stuff) has been around a long time, hasn't it?

[celedhring]

This particular plane was built in 1990, so it wasn't all that modern. Maybe it didn't have all the state-of-art failsafe systems, although I presume these things are upgraded throughout their service life.

[KRonn]

16 students and two teachers from small town high  school...damn. 😕

[DGuller]

That seems plausible in theory, but given how advanced they are, it seems unlikely that such a fail safe would not include something as basic as "Oh, btw, while descending in this critical situation, don't descend so low that you fly into the ground".

There is a difference between "don't fly so low you hit the ground" and "I'm so smart I can see that mountain right in front of us."  I don't think there is any such thing as an autopilot that can see ahead of the plane.

What about this: http://en.wikipedia.org/wiki/Terrain_awareness_and_warning_system ?

[grumbler]

I dunno, gps and terrain mapping and radar ground avoidance and all that?

You could certainly be correct that perhaps the fail safe isn't sophisticated enough to account for that, but I would be a little surprised if it wasn't on these modern planes. The dang things can land themselves, right? Terrain avoidance (and this is gross terrain avoidance, not nap of the earth type stuff) has been around a long time, hasn't it?

GPS doesn't tell you about that mountain ahead, just about your current latitude and longitude.  These aircraft wouldn't have been fitted with "terrain mapping" radar, nor can an airliner autopilot connect to terrain mapping radar (which is used in bombers, not airliners, because of the stresses it places on the plane and crew).  You need to consider that mountains feature massive changes in terrain (kinda by definition) and radar altimeters just give you the distance to the ground now, not the distance to the ground ahead of you.  The kind of system that could predict the lay of the land ahead of the aircraft such that an airliner could automatically fly through mountains doesn't exist, as far as i know.  If the land were relatively flat (no mountains higher than the minimum altitude allowed by the automatic system) the plane would presumably fly until the crew recovered or the plane ran out of fuel.  That wasn't the case here, though.