Air France Flight 447 report

[Skeptical Greg]

Someone has put this spreadsheet, unfortunately just as a jpg here, but it is very good.

Thanks for that ... It actually has all the data from the flight data recorder..
Very informative..

Everything else I read indicated there was no stick priority control ..

 

[LTC8K6]

There was some confusion for the PF. When the plane stalled, the airspeed dropped so low the stall warning stoppped, as the warning system does not function when air speed is too low. When he finally did dip the nose, the airspeed picked up and the stall warning came on again. So he pulled back, because that stopped the stall warning.

Yes, I think that was the case a few times, but not for all of the stall warnings. We can see that in the data.

 

[LTC8K6]

http://cdn-www.airliners.net/aviation-photos/photos/7/3/2/1850237.jpg

The red button disconnects the A/P with a single push, and gives your stick priority with a double push.

If the A/P is already off, then it's just the priority button.

 

[Skeptical Greg]

According to the spreadsheet, it all played out in less than 5 minutes .. Mind boggling..

 

[stilicho]

I really enjoy that show, especially for the investigation stories. Pitot tube blockage, distrust of instruments, not seeing the big picture, pilot communication failure, and continuing to pull back on the stick with stall warning, are some features of the following accidents and an incident related on the show:

China Airlines Flight 006^WP
Birgenair Flight 301^WP
Aeroperú Flight 603^WP
Colgan Air Flight 3407^WP

All are on YT.

Among my favourites are the ones on the Gimli Glider, Air Canada Flight 143^WP, The Heathrow Enigma, British Airways Flight 38^WP, and Falling From The Sky, British Airways Flight 9^WP, where the pilots overcame trouble and everyone on board survived. They're all good, of course, and every time I board a plane I look at it in admiration. It's almost hard to believe that this technology started out as a something like a motorised bicycle with canvas attached to it. If I had a bucket list, one of the items would be to be a gunner on an Airco_DH.2^WP.

The intriguing part about Flight 447 is that the pitot tube issue (something I'd honestly never heard of until watching Mayday!) fixed itself about half way into the crisis. It was the lack of communication, inexperience of one of the pilots, vague command structure on the flight deck, and other largely human errors that brought the plane down. Weather and aircraft design played a part but those factors were not nearly as significant as I see it.

 

[RecoveringYuppy]

The intriguing part about Flight 447 is that the pitot tube issue (something I'd honestly never heard of until watching Mayday!) fixed itself about half way into the crisis.

Wasn't it likely fixed by the de-icing system?

 

[stilicho]

I didn't mean to sound like I disagreed with you. Most of those stall warnings were real, and it is strange that they seemed to ignore them.

I guess we will never know why the PF made that initial rapid climb after the A/P disconnect.

Wasn't the fellow pulling back throughout because of the weather?

 

[Daald]

The Colgan Air incident has a link to http://www.flyingmag.com/pilots-places/pilots-adventures-more/going-direct-push-or-pull which might explain that guy's tendency to pull the stick back.

It seems the problem might be systematic by the training in stall recovery where they can't lose more than 100 ft to recover. This was changed in FAA regulations it seems after Colgan Air incident.

Still doesn't explain why he kept pulling after other pilot took control from him and why he never announced. It does explain why he was still confused to the end though.

 

[I Ratant]

Wow, that brought back memories. I used to fly quite often to Saudi (as a passenger) on a Tristar when my dad worked there in the early 80s. Occasionally it'd be a 747.
I remember an incident where there was fire on a Tristar and the whole roof of the plane was peeled off. Fortunately not a plane I was on, but I saw it sat on the tarmac.
...?

.
That airplane had a cabin fire when some sheepchaser's hibachi overturned while he was cooking dinner.
It returned to the airport and landed, on fire.
All the exit doors were so jammed by frantic people; none of them opened.
The fire department was guarding the King's airplane, which was due to depart, and would not come to the aid of the plane on fire.
Everyone on board died.

 

[I Ratant]

The stall warning is one of the most fundamentally important warnings a pilot can get. It astonishes me that the warning was ignored to the extent it was. Has there ever been a case where a false stall warning was issued by the avionics of a commercial jetliner?

.
We were testing the terrain avoidance system on the Tristar, and were making a low pass across Santa Catalina Island, just in and out of the low clouds..
The system activated, with "PULL UP! PULL UP!".. the PIC turned to the avionics guys and asked if they were pulling breakers, as they were kwown to do.....
Looking out the side window, I got this photo of the Catalina VOR........ waaay too close to us!
And the terrain avoidance system triggers on approaching Burbank from the north, as the plane passes over the San Gabriels.
When we first started testing the system, the coneheads had the plane dive over the mountain to the west of Palmdale, to see if the system would activate on the upgoing slope on the other side of Leona Valley. It was that method was fraught.... so they found an isolated peak out in the desert with the proper slope rate that would trigger the system when flying over, in level flight.

 

[AdMan]

The Colgan Air incident has a link to http://www.flyingmag.com/pilots-places/pilots-adventures-more/going-direct-push-or-pull which might explain that guy's tendency to pull the stick back.

It seems the problem might be systematic by the training in stall recovery where they can't lose more than 100 ft to recover. This was changed in FAA regulations it seems after Colgan Air incident.

Still doesn't explain why he kept pulling after other pilot took control from him and why he never announced. It does explain why he was still confused to the end though.

I can understand the intent to minimize altitude loss when recovering from stalls, but the Air France pilot didn't even start trying to recover from it--he kept pulling back on the stick even after the stall alarm started going off. It doesn't seem rational.

From the PM article:

Perhaps spooked by everything that has unfolded over the past few minutes—the turbulence, the strange electrical phenomena, his colleague's failure to route around the potentially dangerous storm—Bonin reacts irrationally. He pulls back on the side stick to put the airplane into a steep climb, despite having recently discussed the fact that the plane could not safely ascend due to the unusually high external temperature.

...Almost as soon as Bonin pulls up into a climb, the plane's computer reacts. A warning chime alerts the cockpit to the fact that they are leaving their programmed altitude. Then the stall warning sounds....

All pilots are trained to push the controls forward when they're at risk of a stall so the plane will dive and gain speed.

The Airbus's stall alarm is designed to be impossible to ignore. Yet for the duration of the flight, none of the pilots will mention it, or acknowledge the possibility that the plane has indeed stalled—even though the word "Stall!" will blare through the cockpit 75 times. Throughout, Bonin will keep pulling back on the stick, the exact opposite of what he must do to recover from the stall.

 

[Graham2001]

Other planes survived icing of the pitot. If you have enough events like this with enough crews, the odds are that one of them will screw up. When the event started, they should have consulted the manual for the correct procedure to follow.

The whole event took place in about four minutes. I am sure that if they could have stopped time, had a good think about what was happening and discussed it calmly amongst themselves, they would have worked out what they should do and have survived. They didn't have that luxury. The idea that the jet was falling like a stone out of the sky never occurred to the pilot flying.

It's happened in the past:

...the probable cause of this accident was the loss of control of the aircraft because the flightcrew failed to recognize and correct the aircraft's high angle of attack, low-speed stall and its descending spiral. The stall was precipitated by the flightcrew's improper reaction to erroneous airspeed and Mach indications which had resulted from a blockage of the pitot heads by atmospheric icing.

Northwest Airlines Flight 6231 (01/12/1974)

http://en.wikipedia.org/wiki/Northwest_Airlines_Flight_6231

 

[stilicho]

It's happened in the past:



Northwest Airlines Flight 6231 (01/12/1974)

http://en.wikipedia.org/wiki/Northwest_Airlines_Flight_6231

It looks like Wikipedia needs to update that article because it says that the flight we're discussing suffered the same issue that led to its loss.

Am I missing something though? When I read that article it appears that the issue was not the pitot tubes because that was fixed during the recovery effort. The problem was that the inexperienced pilot kept trying to climb over the weather without knowing exactly what the consequences of his actions were. From the earlier cite from a_unique_person, it appears that the PF really needed to hand over control of the aircraft to the more experienced pilot.

I'll repeat the disclaimer that I'm not a pilot and have no experience in the field but a circumspect analysis tells me that both the captain and the other more senior pilot would have done the right thing immediately they had full control of the aircraft. It almost seems like the opposite issue as downed Flash Airlines Flight 604^WP (another one featured on Mayday!) where the pilot evidently suffered vertigo or some other sort of spatial disorientation and the less experienced co-pilot refused to challenge the senior pilot's authority although he knew the plane was in trouble at the inception of the crisis.

What do you do then? How do you test that? Do you set up simulations where known or knowable issues arise but in some cases the senior officer must take control while in others he must surrender control to the co-pilot?

 

[a_unique_person]

What do you do then? How do you test that? Do you set up simulations where known or knowable issues arise but in some cases the senior officer must take control while in others he must surrender control to the co-pilot?

That appears to be the core problem. You have two people, one more senior than the other, and they both disagree. Sometimes the more senior is right, sometimes the more junior. How do you resolve the issue? Fisticuffs? Yelling and shouting? Teneriffe is a good example of a senior pilot screwing up majorly. And this Wiki articles refers to CRM, so the issue is now part of standard training. Didn't work in this case, though.

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

Less experienced flight crew members were encouraged to challenge their captains when they believed something was not correct, and captains were instructed to listen to their crew and evaluate all decisions in light of crew concerns. This concept would later be expanded into what is known today as Crew Resource Management. CRM training is now mandatory for all airline pilots.[5]

 

[stilicho]

That appears to be the core problem. You have two people, one more senior than the other, and they both disagree. Sometimes the more senior is right, sometimes the more junior. How do you resolve the issue? Fisticuffs? Yelling and shouting? Teneriffe is a good example of a senior pilot screwing up majorly. And this Wiki articles refers to CRM, so the issue is now part of standard training. Didn't work in this case, though.

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

This happens in all organisations, of course. The board chairman can announce a decision that everyone seated at the table knows full well is suicidal or, alternately, relinquish control to some bright-eyed newbie director who is completely divorced from reality. I would actually like to see some of the crisis/crew management from the air transportation industry transferred to other businesses and see how it works. The safety record of the airline industry ought to be a beacon for HR professionals looking reduce the effects of human error.

Won't happen but it would be nice.

 

[AdMan]

That appears to be the core problem. You have two people, one more senior than the other, and they both disagree. Sometimes the more senior is right, sometimes the more junior. How do you resolve the issue? Fisticuffs? Yelling and shouting?

Well, obviously there's no way to know before the fact which one--the less experienced or the more experienced--of the two is going to be right, but surely you would expect in an emergency that the more senior person is automatically given the controls if there's a choice, wouldn't you? Why did the less-experienced pilot keep grabbing the controls (and, more important, why did the systems allow him to do that?)? I still don't get that part.

 

[LondonJohn]

I can understand the intent to minimize altitude loss when recovering from stalls, but the Air France pilot didn't even start trying to recover from it--he kept pulling back on the stick even after the stall alarm started going off. It doesn't seem rational.

It wasn't rational at all - it was grossly bad airmanship. I used to hold a PPL, and my father was an RAF fast jet pilot, and the Air France pilots made a huge number of errors that compounded themselves to cause the crash. There's an adage, which is usually true, that most air crashes - especially where pilot error plays a major part - require a long chain of errors/mishaps to congregate in a "perfect storm" in order for a crash to happen. Of course, not many people ever hear about the numerous times where a shorter chain of errors/mishaps take place which don't result in a crash. But there are a lot of such events.

In this instance, the two junior pilots seemed to make two extremely serious aerodynamic errors that were the genesis of the eventual crash. Firstly, they failed to understand or apply the basic knowledge that when flying at high altitude, the thinness and oxygen depletion in the atmosphere mean that three of the four forces acting on the aircraft - lift, drag and thrust - are increasingly diminished, while the fourth force - gravity - remains constant. This of course has an increasingly dramatic effect on the way in which one should pilot an aircraft at high altitude. Failure to understand/this principle appears to be the main reason why the pilots manoeuvred the aircraft into a nose-up descent and stall (including, unbelievably, the apparent fact that they flew the aircraft to the limit of its altitude envelope, in a misguided attempt to overfly the weather)

The second basic aerodynamic error the pilots appear to have made is to have egregiously failed to apply standard stall recovery procedures. Regardless of the (temporary) failure of the pitot probes, the pilots should have been under no illusions that they were in a stall. And whether or not they thought that a FBW Airbus was technically incapable of stalling, the stall warning should have instinctively caused them to disengage the autopilot (assuming they thought it was still engaged, although in fact it had disengaged after the pitot probe problem) and perform a manual stall recovery. As plenty of others have already pointed out, if they had pointed the nose down and increased thrust, they would have recovered from the stall within a matter of seconds (depending on the altitude at which they started the recovery). Indeed, had the pilots simply taken their hands and feet off the controls, it's highly likely that the aircraft would have corrected its stall all by itself well before any threat of a crash.

Aside from these two errors related to aerodynamics, there also appear to have been serious errors in communication and CRM, and there may have also been errors in the way Air France trained its pilots to fly these aircraft. But I'd argue that regardless of these other "soft" factors, the shockingly poor airmanship of the pilots was the overwhelmingly major contributor to the crash. I'd argue that someone who'd had four basic flying lessons (and not even a licence), if they had been sat at the controls of that aircraft at the start of the problems, should (and would) have been able to fly the aircraft safely.

As a slight aside, my father was involved in many RAF boards of inquiry into military accidents, but he also had a few former RAF friends who worked for the UK Air Accidents Investigation Branch (AAIB), which investigates civilian accidents. One of my father's good friends was involved in many high-profile investigations, including PanAm 103, Kegworth, and - most notably for him perhaps - the British Airways BAC11 accident where the windscreen blew out, sucking out the captain, who was saved by other crew holding onto his feet and landing the aircraft safely. This incident was featured in an episode of "Mayday" (re-titled "Air Crash Investigation" over here), and my father's friend - Stuart Culling - was the AAIB investigator who cracked the case by using human factors to establish that sloppy (and too time-critical) maintenance procedures had led to bolts of the wrong size having been used to reattach the windscreen during maintenance.

 

[a_unique_person]

In this instance, the two junior pilots seemed to make two extremely serious aerodynamic errors that were the genesis of the eventual crash. Firstly, they failed to understand or apply the basic knowledge that when flying at high altitude, the thinness and oxygen depletion in the atmosphere mean that three of the four forces acting on the aircraft - lift, drag and thrust - are increasingly diminished, while the fourth force - gravity - remains constant. This of course has an increasingly dramatic effect on the way in which one should pilot an aircraft at high altitude. Failure to understand/this principle appears to be the main reason why the pilots manoeuvred the aircraft into a nose-up descent and stall (including, unbelievably, the apparent fact that they flew the aircraft to the limit of its altitude envelope, in a misguided attempt to overfly the weather)

The Pilot not flying gave the PF good advice, to do as little as possible, since the aircraft was flying well, and all that had happened was that one of the pitot tubes was iced over. He also encouraged the PF to lower the nose, and attempted to take control from the PF. So there was a disagreement right there about what to do. The PNF seemed to have the right idea.

 

[Sideroxylon]

.
That airplane had a cabin fire when some sheepchaser's hibachi overturned while he was cooking dinner.
It returned to the airport and landed, on fire.
All the exit doors were so jammed by frantic people; none of them opened.
The fire department was guarding the King's airplane, which was due to depart, and would not come to the aid of the plane on fire.
Everyone on board died.

It appears you are talking about Saudia Flight 163^WP which had a cargo fire for which the cause was not determined.

 

[Molinaro]

I have on a few occasions thought about making a thread to discuss the show "Mayday". It seems I'm not the only one who thoroughly enjoys it.