Armchair air crash investigator • Hacker News Board

Re: Armchair air crash investigator

#111

Post by nknighthb » Mon, Jul 08, 2013, 1:50 AM UTC

CamperBob2 wrote: post #110

nknighthb wrote: post #108

Earlier quoted context omitted.

> 40 years ago we did this stuff on the freakin' Moon. ... > In the "freakin' Moon" example, the human pilot still had to handle the tricky part. Since you're apparently well aware that the Apollo missions were conducted with manual docking and landing, why bring it up? Especially given the relative simplicity of "final approach" on the moon, given the lower gravity, zero wind speed, and slower pace, I don't understa…

Just pointing out that it's not valid to argue that this stuff is impossible, or even impractical.

What "stuff", though? The moon landings were conducted by a human brain in control of a (mostly[1]-)fully-functional machine. How does that translate to fully automated landing of an atmospheric aircraft already experiencing a malfunction?

[1] Actually, the Eagle did experience a computer malfunction that almost caused an abort to the landing before an engineer said they could ignore it. You want a computer to judge for itself whether it can still safely fulfill its mission while malfunctioning?

For further terror, consult the Apollo 12 lightning strike. When the computer is FUBAR, how do you propose it fix itself?

Re: Armchair air crash investigator

#112

Post by marvin » Mon, Jul 08, 2013, 1:58 AM UTC

VladRussian2 wrote: post #104

cpncrunch wrote: post #59

It looks like this was an unstabilized approach right down to the ground. It would be interesting to see what the company SOP is. Any safe airline has a no-fault go-around policy for unstabilized approaches, and you'll actually get in trouble if you continue with an unstabilized approach and you don't go around. From what pilots are saying on the message boards it seems that a lot of Asian airlines have pretty much t…

pretty much looks the same to me - the guy stalled and when he finally, at the last second (actually - well past the last second), decided to go around, he did jerk up the nose and that increased the stall, so they fell. Reminds me about the AirFrance fall in the Atlantic some years ago - that guy was trying to gain altitude by jerking the nose up (i.e. increasing the "angle of attack") instead of "pressing the accel…

If this is what really happened, I'll say the same thing I said then - it shocks me that airline pilots with thousands of flight hours can make the most elementary piloting mistake possible.

But I've read accident reports before, and it's rarely a good idea to speculate. I won't have an opinion about this until the official report is published.

Re: Armchair air crash investigator

#113

Post by CamperBob2 » Mon, Jul 08, 2013, 2:02 AM UTC

nknighthb wrote: post #111

CamperBob2 wrote: post #110

Earlier quoted context omitted.

Just pointing out that it's not valid to argue that this stuff is impossible, or even impractical.

What "stuff", though? The moon landings were conducted by a human brain in control of a (mostly[1]-)fully-functional machine. How does that translate to fully automated landing of an atmospheric aircraft already experiencing a malfunction? [1] Actually, the Eagle did experience a computer malfunction that almost caused an abort to the landing before an engineer said they could ignore it. You want a computer to judge…

So, just to make sure I don't misrepresent your position, you're saying that the people who built and programmed this hardware ( http://www.space.com/16878-mars-rover-landing-sky-crane-guid... ) couldn't safely land a 777 in SFO (or, for that matter, an A320 in the Hudson) any day of the week. Is this the case?

Re: Armchair air crash investigator

#114

Post by gcv » Mon, Jul 08, 2013, 2:04 AM UTC

jervisfm wrote: post #18

It goes without saying that my qualifications in aviation matters are only as an aviation enthusiast and for the full cause of the accident, we'll have to wait for the NTSB report (which has access to vital black box data and cockpit recordings). However, I did give this accident some thought as well given the circumstances of the accident and came the pretty much the same final conclusion as the OP. An airline pilot…

So the price of automation is eternal vigilance? Reminds me of the old argument that overuse of calculators means people have lost the ability to do mental arithmetic.

Re: Armchair air crash investigator

#115

Post by nknighthb » Mon, Jul 08, 2013, 2:06 AM UTC

CamperBob2 wrote: post #113

nknighthb wrote: post #111

Earlier quoted context omitted.

What "stuff", though? The moon landings were conducted by a human brain in control of a (mostly[1]-)fully-functional machine. How does that translate to fully automated landing of an atmospheric aircraft already experiencing a malfunction? [1] Actually, the Eagle did experience a computer malfunction that almost caused an abort to the landing before an engineer said they could ignore it. You want a computer to judge…

So, just to make sure I don't misrepresent your position, you're saying that the people who built and programmed this hardware ( http://www.space.com/16878-mars-rover-landing-sky-crane-guid... ) couldn't safely land a 777 in SFO (or, for that matter, an A320 in the Hudson) any day of the week. Is this the case?

What part of the skycrane experienced serious damage or malfunction that the software corrected for?

The whole point is we're not talking about when things go according to plan.

For that matter, how many times has the skycrane been used? What is its safety record? If you go ask the guys at JPL how many times out of 1000 they think it'll work perfectly, what will they say?

Incidentally, not cool moving goalposts.

Re: Armchair air crash investigator

#116

Post by cpncrunch » Mon, Jul 08, 2013, 2:15 AM UTC

marvin wrote: post #112

VladRussian2 wrote: post #104

Earlier quoted context omitted.

pretty much looks the same to me - the guy stalled and when he finally, at the last second (actually - well past the last second), decided to go around, he did jerk up the nose and that increased the stall, so they fell. Reminds me about the AirFrance fall in the Atlantic some years ago - that guy was trying to gain altitude by jerking the nose up (i.e. increasing the "angle of attack") instead of "pressing the accel…

If this is what really happened, I'll say the same thing I said then - it shocks me that airline pilots with thousands of flight hours can make the most elementary piloting mistake possible. But I've read accident reports before, and it's rarely a good idea to speculate. I won't have an opinion about this until the official report is published.

Pilots are human, and they make mistakes. Good training, having two pilots on the flightdeck and having good SOPs should prevent anything like this ever happening. It looks like training and/or SOPs were severely lacking here.

As well as the "don't waste our company money doing a go-around" fuckwitted notion, people are saying that Asian airlines don't like doing visual approaches period. Therefore whenever the pilot is required to do a visual approach, he/she will be severely lacking in the skills to do it.

Re: Armchair air crash investigator

#117

Post by krisoft » Mon, Jul 08, 2013, 2:30 AM UTC

nknighthb wrote: post #109

lisper wrote: post #96

Earlier quoted context omitted.

Actually, it is extremely rare for a human pilot to come up with a "creative solution" to an emergency. The vast majority of emergency responses are established procedures for which pilots train. Most of the time they're following a check list. I can only think of a single example of a "creative" response to an in-flight emergency that actually helped, and that was UA232 in 1989.

Is it standard procedure to land A320s in the Hudson? Prior to 2009, how likely do you think it would have been for someone to have programmed an autopilot with such a capability? Do pilots typically glide unpowered 767s to landings at abandoned military airfields? (A result, incidentally, that could not be reproduced by other crews in simulators; are you sure it's the crews, and not inadequate programming? Still tru…

Emergency landing on water is "standard procedure". You might have the impression that it's something which was creatively invented by the pilot at a moments notice, but it's really not. The engineers designed the airplane with the capability, included advice and checklist in the operation manual, they even put a button labeled "ditch" on the dash! Can't really see why they could not make such an autopilot program.

Re: Armchair air crash investigator

#118

Post by VladRussian2 » Mon, Jul 08, 2013, 2:33 AM UTC

marvin wrote: post #112

VladRussian2 wrote: post #104

Earlier quoted context omitted.

pretty much looks the same to me - the guy stalled and when he finally, at the last second (actually - well past the last second), decided to go around, he did jerk up the nose and that increased the stall, so they fell. Reminds me about the AirFrance fall in the Atlantic some years ago - that guy was trying to gain altitude by jerking the nose up (i.e. increasing the "angle of attack") instead of "pressing the accel…

If this is what really happened, I'll say the same thing I said then - it shocks me that airline pilots with thousands of flight hours can make the most elementary piloting mistake possible. But I've read accident reports before, and it's rarely a good idea to speculate. I won't have an opinion about this until the official report is published.

well, until report is out, we're here to speculate (or to read a good speculation if we're lucky :). From the Flightaware data the plane had 109kts at 100feet altitude before the seawall. The stall speed of 777 is about 110kts (its Vat is ~140, and it is 1.3 of the stall). And the speed was falling as the next recording is 85kts. While we can only guess about the original cause - pilot error or hardware, etc... - the stall seems to be there.

Re: Armchair air crash investigator

#119

Post by lisper » Mon, Jul 08, 2013, 2:36 AM UTC

nknighthb wrote: post #109

lisper wrote: post #96

Earlier quoted context omitted.

Actually, it is extremely rare for a human pilot to come up with a "creative solution" to an emergency. The vast majority of emergency responses are established procedures for which pilots train. Most of the time they're following a check list. I can only think of a single example of a "creative" response to an in-flight emergency that actually helped, and that was UA232 in 1989.

Is it standard procedure to land A320s in the Hudson? Prior to 2009, how likely do you think it would have been for someone to have programmed an autopilot with such a capability? Do pilots typically glide unpowered 767s to landings at abandoned military airfields? (A result, incidentally, that could not be reproduced by other crews in simulators; are you sure it's the crews, and not inadequate programming? Still tru…

> Is it standard procedure to land A320s in the Hudson?

Yes, ditching an airplane that has lost all of its engines is a standard emergency procedure.

> Prior to 2009, how likely do you think it would have been for someone to have programmed an autopilot with such a capability?

What difference does that make? I'm not saying it's a good idea to take pilots out of the cockpit right now, I'm just saying it's a lot more plausible than most people think. The main limiting factor is politics, not technology.

> Are you willing to bet your life that the computer on a 737 that looked like this[1] could find its way to a safe landing?

Sure, why not? Losing the top of the fuselage looks dramatic, but it probably doesn't change the flight characteristics all that much. Also, very good adaptive control algorithms exist that could almost certainly handle this.

Also, you're cherry-picking your anecdotes. There are plenty of examples of flights that would almost certainly have ended safely but for some stupid mistake the pilot made. Controlled flight into terrain accidents, for example, are much more common than heroic rescues, and they could be entirely eliminated if you took human pilots out of the loop.

Re: Armchair air crash investigator

#120

Post by nknighthb » Mon, Jul 08, 2013, 2:41 AM UTC

krisoft wrote: post #117

nknighthb wrote: post #109

Earlier quoted context omitted.

Is it standard procedure to land A320s in the Hudson? Prior to 2009, how likely do you think it would have been for someone to have programmed an autopilot with such a capability? Do pilots typically glide unpowered 767s to landings at abandoned military airfields? (A result, incidentally, that could not be reproduced by other crews in simulators; are you sure it's the crews, and not inadequate programming? Still tru…

Emergency landing on water is "standard procedure". You might have the impression that it's something which was creatively invented by the pilot at a moments notice, but it's really not. The engineers designed the airplane with the capability, included advice and checklist in the operation manual, they even put a button labeled "ditch" on the dash! Can't really see why they could not make such an autopilot program.

You completely misunderstand. I wasn't talking about a generic "emergency landing on water".

A plane suddenly loses power in a highly urbanized area. It's very near multiple airports. Prior to 2009, I have no expectation that an autopilot would have been equipped to judge whether it should attempt to land in a heavily-trafficked river. (I further have no expectation that it would have been equipped to notice in the highly plausible scenario of one or more small boats being in the way.)

It's not a question of landing on water, it's a question of making the decision to do so and where.

Humans have the judgement gained by a lifetime of learning. Computers only have what it occurs to us to put into them while we're sitting safe and sound in our little offices pushing little buttons that don't threaten our lives.