What really happened aboard Air France 447 • Hacker News Board

Re: What really happened aboard Air France 447

#61

Post by ookblah » Thu, Dec 08, 2011, 5:28 AM UTC

Such a tragedy...

Forgive my ignorance, maybe some pilots can shed some light on this. In the article it mentions that even though the plane was flying in "alternate" mode, my understanding is that it still has limits to what inputs can be given.

That said, even if autopilot is off, why wouldn't the computer have emergency functions to negate strange situations like this? When would pulling completely back on the stick while losing altitude rapidly ever be considered within the range of normal?

Re: What really happened aboard Air France 447

#62

Post by fr0sty » Thu, Dec 08, 2011, 5:35 AM UTC

Also potentially of interest:

http://news.ycombinator.com/item?id=3327828

In several of these transcripts you can read the pilots reactions to various warnings (including stall warnings) which might be interesting to look at for comparison.

Re: What really happened aboard Air France 447

#63

Post by sandee » Thu, Dec 08, 2011, 5:46 AM UTC

runningdogx wrote: post #29

I've followed the discussion of the AF447 investigation on several flight discussion forums. The PF (Bonin) apparently never became aware of his angle of attack (once the airplane fully stalled, AOA was absurdly high). He did not seem to be aware that his constant inputs had caused the Airbus's THS (trimmable horizontal stabilizer, horizontal flaps on the tail) to deflect to maximum in order to try to keep the nose u…

>at night, over an ocean, in a storm, with no visibility, in possibly significant turbulance

Instead of finding out strategies on how to fly under these circumstances, why can't the plane change its course, if they anticipate the flying route to have these conditions. How about running some reconnaissance drones in the popular routes if they suspect a bad weather and want to check out. Or try out better weather monitoring methods and tools on these routes.

Edit : Ok my mistake.On reading again, the article states "Unlike other planes' crews flying through the region, AF447's flight crew has not changed the route to avoid the worst of the storms. ".

Re: What really happened aboard Air France 447

#64

Post by biot » Thu, Dec 08, 2011, 5:50 AM UTC

rguzman wrote: post #39

bdonlan wrote: post #34

Earlier quoted context omitted.

Surely he's been in exciting situations in simulators, at least? (And if not, he probably should arrange for some simulated excitement :)

oh yeah... due to a complicated set of fortunate circumstances i once got an observer seat during re-current simulator training (happens every 6 months). all the flying i've ever done was on ms flight simulator, but i know enough to read gauges and what not. it was so intense that even i was too stressed to finish paying attention to the whole session. lots of exciting situations there. and stop calling me surely.

Training in a flight simulator is an entirely different thing... altogether!

Re: What really happened aboard Air France 447

#65

Post by andrewfelix » Thu, Dec 08, 2011, 5:50 AM UTC

I physically sweated and got an acid taste in my mouth while reading that transcript.

Re: What really happened aboard Air France 447

#66

Post by celoyd » Thu, Dec 08, 2011, 5:52 AM UTC

blinkingled wrote: post #18

The men are utterly failing to engage in an important process known as crew resource management, or CRM. They are failing, essentially, to cooperate. It is not clear to either one of them who is responsible for what, and who is doing what. I have read a few other transcripts from crashed planes and this seems to be the most common and significant contributor. I see variations of this problem almost daily in my day to…

CRM is interesting stuff. It got popular in aviation after the crash of United 173,[0] where the crew was so involved in a serious landing gear problem that the only one who noticed that they were running out of fuel apparently didn’t want to be rude enough to insist on dealing with it before it was too late. In that case, it was generally interpreted as too much respect for authority: the junior crew member didn’t want to distract the captain by raising the fuel problem too often. So that can go both ways.

United 173 was only a particularly good example of exactly what you point out: many plane crashes happen when individual crew members miss simple things that others could easily correct but don’t. After flight crews got CRM-based training, the incidence of this kind of thing went down measurably. But as I was reading this transcript, it was eerie to see how little they were applying it. Why were they practically silent? If they’d each volunteered a little more information about observations, intentions, and actions (“I’m leaving the stick full forward”), they’d have been fine.

Anyway, I think CRM has some pretty clear applications to normal business environments, but especially to startups. The jumbled panorama of interlocking and quickly developing options confronting a small team of coders is not unlike an aviation emergency, though at a slower pace.

0. http://en.wikipedia.org/wiki/United_Airlines_Flight_173

Re: What really happened aboard Air France 447

#67

Post by wavephorm » Thu, Dec 08, 2011, 5:56 AM UTC

maeon3 wrote: post #27

Pilot stalls the plane out of panic to get out of the storm, ignoring 75 reminders that you are stalling and losing altitude, does nothing to remedy the stall until it is too late. I expect blunders like that from drunk drivers.

This is a lot more akin to a sober driver with a car that constantly blinks "service" and not realizing that they're stepping on the gas instead of the brakes, and it's not pedals, but a joystick, and it's a blizzard, and you can't feel simply by inertia which which direction you're going.

Re: What really happened aboard Air France 447

#68

Post by bhickey » Thu, Dec 08, 2011, 5:57 AM UTC

afterburner wrote: post #50

runningdogx wrote: post #29

I've followed the discussion of the AF447 investigation on several flight discussion forums. The PF (Bonin) apparently never became aware of his angle of attack (once the airplane fully stalled, AOA was absurdly high). He did not seem to be aware that his constant inputs had caused the Airbus's THS (trimmable horizontal stabilizer, horizontal flaps on the tail) to deflect to maximum in order to try to keep the nose u…

You suggest that one problem might be that Bonin didn't know his angle of attack. Alternately, I remember a similarity here with an Egypt Air flight that went down when some instruments went dead: when one of the instruments experienced malfunction, the pilots suddenly found it hard to believe anything the computer was saying. So maybe, on some level, Bonin dismissed the stall warning because the speed sensor had fai…

The NTSB concluded that 990 was a homicide. A relief pilot assumed control after take-off and then deliberately crashed the aircraft. From what I hear, it wasn't a fun week at the RI Medical Examiner's office.

Re: What really happened aboard Air France 447

#69

Post by jrockway » Thu, Dec 08, 2011, 5:58 AM UTC

sliverstorm wrote: post #43

jarcoal wrote: post #40

Earlier quoted context omitted.

Supposedly they do de-ice themselves, but that obv didn't work properly here.

Ah, I was not aware they already could. My next question is why not make themselves de-ice better? This maybe seems trollish or silly, but in all seriousness, if your sensors aren't good enough, first rule out improving the sensors before you try to compensate with the system.

There is other debris that can clog pitot tubes. Birgenair Flight 301 crashed because some wasps built a nest in a pitot tube during an extended layover:

http://en.wikipedia.org/wiki/Birgenair_Flight_301

189 people died.

(Also note the failure to react properly to the stall warnings. This comes up again and again.)

Re: What really happened aboard Air France 447

#70

Post by antoinehersen » Thu, Dec 08, 2011, 5:59 AM UTC

sandee wrote: post #63

runningdogx wrote: post #29

I've followed the discussion of the AF447 investigation on several flight discussion forums. The PF (Bonin) apparently never became aware of his angle of attack (once the airplane fully stalled, AOA was absurdly high). He did not seem to be aware that his constant inputs had caused the Airbus's THS (trimmable horizontal stabilizer, horizontal flaps on the tail) to deflect to maximum in order to try to keep the nose u…

>at night, over an ocean, in a storm, with no visibility, in possibly significant turbulance Instead of finding out strategies on how to fly under these circumstances, why can't the plane change its course, if they anticipate the flying route to have these conditions. How about running some reconnaissance drones in the popular routes if they suspect a bad weather and want to check out. Or try out better weather monit…

Not changing course like almost all other flight that night was their first mistake.