Why did Air France 447 go down?

[dagger]

http://online.wsj.co..._LEFTTopStories

Why won't they just come out and say it? They flew through a thunderstorm. Heavy icing and turbulence at fl350??

http://www.bloomberg.com/news/2011-05-27/air-france-crash-probe-shows-jet-stalled-plunged-3-1-2-minutes-to-ocean.html

[Miles]

While the original failure may not have brought he aircraft down, it was the ROOT cause of the accident. All subsequent issues that arose from that would never have occurred if the root failure did not occur. While the ultimate cause of the crash could well have been due to actions performed by the crew, those actions were being performed while dealing with the original issue.

We have seen this in the past where crews become entangled in troubleshooting the issue and diverting their attention from flying the aircraft. It was mentioned earlier that perhaps adding the third crew mewmber back into the flight deck may be a solution. This is not necessarily true as we have seen the same distractions happen in a 3 man cockpit as well (Flight 401 in FLA). Simply the basics of airmanship need to take the forfront when anything happens and sometimes we forget this. AVIATE, NAVIGATE, COMMUNICATE. Fly the plane is always #1 the rest can wait until you have your s#$% together.

Having said all that we can wait for the preliminary report where they will undoubtedly blame the pilots.

From that article I quoted, it looks like the pilots aren't solely to blame. The Airline can also be blamed for not training for a long standing known issue with the aircraft, and the manufacturer can also be blamed for being slow to fix the problem.

But I say again, that failure should NOT have resulted in a hull loss.

Sorry, in a hurry, gotta go Aviate, Navigate and Communicate.

[Jack Sparrow]

Looks like the BEA has released their prelim FDR and CVR discoveries:

BEA AF 447 Update

4S

[Moon The Loon]

While the original failure may not have brought he aircraft down, it was the ROOT cause of the accident. All subsequent issues that arose from that would never have occurred if the root failure did not occur. While the ultimate cause of the crash could well have been due to actions performed by the crew, those actions were being performed while dealing with the original issue.

We have seen this in the past where crews become entangled in troubleshooting the issue and diverting their attention from flying the aircraft. It was mentioned earlier that perhaps adding the third crew mewmber back into the flight deck may be a solution. This is not necessarily true as we have seen the same distractions happen in a 3 man cockpit as well (Flight 401 in FLA). Simply the basics of airmanship need to take the forfront when anything happens and sometimes we forget this. AVIATE, NAVIGATE, COMMUNICATE. Fly the plane is always #1 the rest can wait until you have your s#$% together.

Having said all that we can wait for the preliminary report where they will undoubtedly blame the pilots.

Boe

The ROOT cause of the accident was being where they were in the first place, with especially hazardous ITCZ weather forecast for that flight, and the Captain in the bunk unable to navigate successfully through severe weather. Your root CAUSE seems not to have been a cause at all, moreso a RESULT of past actions/inactions.

Your preaching is getting a little thin, especially when the facts aren't all in yet.

[Moon The Loon]

http://www.bloomberg.com/news/2011-05-27/air-france-crash-probe-shows-jet-stalled-plunged-3-1-2-minutes-to-ocean.html

"The analysis shows that the pilots had favored climbing above the approaching stormy clouds but were prevented from doing so because it wasn’t cold enough for the jet to ascend to that level."..."According to the BEA, the co-pilots continued to increase the angle of climb, rising rapidly from 35,000 feet to 37,500 feet. When a third stall warning sounded, they continued to pull back on the controls with the engines set to full thrust and rose to about 38,000 feet, where the plane entered a stall."

wow

[Kip Powick]

Reluctant to add...cause I am pretty well a 'nut and bolt" guy but to me the cause of the accident, based on what I have read , so far, was the inexperience of the two guys sitting in the front....seems pretty simple to me.

Basic aerodynamic knowledge, basic airmanship, basic actions in the event of an emergency...............all went out the window and the whole mess snowballed with NO ONE really taking control of the situation.

I am more amazed that the 4 ringer slept through the whole mess..if that was in fact what he did. Must have been a good party the night before.

I have given control to 2 FOs before, (Mil) and been in the prone position on the bunk, (C130) but the moment there was a change in engine noise or aircraft attitude...I was awake.

[Gumbi]

Reluctant to add...cause I am pretty well a 'nut and bolt" guy but to me the cause of the accident, based on what I have read , so far, was the inexperience of the two guys sitting in the front....seems pretty simple to me.

Basic aerodynamic knowledge, basic airmanship, basic actions in the event of an emergency...............all went out the window and the whole mess snowballed with NO ONE really taking control of the situation.

I am more amazed that the 4 ringer slept through the whole mess..if that was in fact what he did. Must have been a good party the night before.

I have given control to 2 FOs before, (Mil) and been in the prone position on the bunk, (C130) but the moment there was a change in engine noise or aircraft attitude...I was awake.

Well, according to this report from AP, the captain made it back the the FD just before the "descent" began... so he apparently didn't sleep through it all

"At about this time, "The speed displayed on the left side increased sharply," the report said. The aircraft was then at an altitude of about 37,500 ft.

The report said that at this time co-pilot PNF tried several times to call the captain back to the cockpit.

The aircraft then climbed to 38,000 ft and at around four hours 11 minutes and 40 seconds into the flight, the captain re-entered the cockpit. During the following seconds all of the recorded speeds became invalid and the stall warning stopped, the report said.

Co-pilot PF said "I don't have any more indications", and the co-pilot PNF said "we have no valid indications."

[boestar]

It seems there was a failure to properly control a stalled situation that was broought on by faulty speed indications and an inproper reaction to them. Storm or no storm the airspeed indication on both the primary and standby instruments went "Invalid". All indications relayed to the pilot (according to the report above) after that point, pointed to a Stall. The proper reaction to a stall in not to climb.

I do know there is more to come in the investigation and I am NOT PREACHING to any one only pointng out that in many past situations distraction has prevented pilots from Flying first. It appears that this is not the case based on the current findings. The pilots were trying to fly the plane.

I have hundreds of reports and transcripts of investigations and reports of past accidents and incidents and through the years you can see the same mistakes happenning over and over again.

I never pointed fingers at anyone, only pointed out MY opinion. When the FACTS are presented I will accept them.

[props2you]

The initial speculation on the chain of events seems to have been completely accurate: flying directly into the weather, leading to icing of the pitots, leading to the crash.

[Kip Powick]

The initial speculation on the chain of events seems to have been completely accurate: flying directly into the weather, leading to icing of the pitots, leading to the crash.

Thanks for the "Captain" info re sleeping..I missed it.

I think your last posting should have another line in it....

The initial speculation on the chain of events seems to have been completely accurate: flying directly into the weather, leading to icing of the pitots, leading into an inflight condition that was not handled well by the pilots which led to a crash.

I will be the first to admit that I know little about that aircraft types cockpit flight instrument set up but I find the fact that it took over 3 minutes to go from altitude to sea level /impact a very, very long time for 3 pilots, albeit one very inexperienced, to not know they were in a stall and apply the corrective actions.

Would not the cabin pressure decrease alert the crerw that they were descending very fast.???? (close to 10,000fpm)

[boestar]

Kip it was closer to 11000fpm by the report. they were falling like a rock tied to a bullet. The only saving grace is that impact at that speed would have resulted in a quick end.

[RGT2.0]

http://corporate.airfrance.com/en/press/news/article/item/af-447-reaction-dair-france-a-la-note-dinformation-du-bea/

AF 447 - Air France’s reaction to the BEA’s information report

Friday 27 May 2011

On the eve of second anniversary of the AF447 tragedy, Air France and its staff are turning their thoughts to the families of the passengers and crew and wish to express their full solidarity.

The perserverance of the authorities, Airbus and Air France has led to the flight recorders and parts of the aircraft being found after a two-year search. The French Accident Investigation Bureau (BEA) is now able to reveal the sequence of events leading to the crash of flight AF447 from Rio to Paris on 1 June 2009.

This description of the facts therefore replaces the assumptions that have been made over the past two years.

It appears that the flight deck crew was monitoring the changing weather conditions and thus altered the flight path, that the initial problem was the failure of the speed probes which led to the disconnection of the autopilot and the loss of the associated piloting protection systems, and that the aircraft stalled at high altitude. It also appears that the flight captain quickly interrupted his rest period to regain the cockpit. The crew, made up of three skilled pilots, demonstrated a totally professional attitude and were committed to carrying out their task to the very end and Air France wishes to pay tribute to them.

All the data collected must now be analyzed. It will only be at the end of this complex task, which requires patience and precision, that the BEA will be able to establish the causes that led to the disaster.....

[Kip Powick]

It also appears that the flight captain quickly interrupted his rest period to regain the cockpit. The crew, made up of three skilled pilots, demonstrated a totally professional attitude and were committed to carrying out their task to the very end and Air France wishes to pay tribute to them

A typical company PR spin but really...what else could they say/admit.

RIP to those that were unfortunate victims of......................?

[Jaydee]

Partial Voice Recorder transcript

http://www.avherald.com/h?article=41a81ef1/0068&opt=0

[Moon The Loon]

"At 02:12:02Z the thrust levers were placed into idle, the pilot flying made nose down inputs, the angle of attack reduced and the indicated airspeeds became valid again."

indicated airspeeds became valid again

So where does this take the theory about broken pitot heads? Or are these computed IAS's from the AoA's?

[boestar]

This should have been anindication that the aircraft was on its way to actually flying again. The reason they were not indicating is because there was noair flowing through them it was flowing across them. Once the nose was pointed down yjey became active because the pilots reaction was CORRECT. Why did theu change srategies.

[Moon The Loon]

This should have been anindication that the aircraft was on its way to actually flying again. The reason they were not indicating is because there was noair flowing through them it was flowing across them. Once the nose was pointed down yjey became active because the pilots reaction was CORRECT. Why did theu change srategies.

You've lost it.

[Specs]

Any Pilots care to clarify a speed question for me?

The decided to ease back to M.8 but 2 minutes later they dropped from 275 kts down to 60. 275 KTS at FL350 is .82.

Either way, (.8 or .82) that seems a bit high when you're heading into heavy turbulence which they had already acknowledged (discussion of reduction to M.80, advice to cabin)

Is that a bit high and what would the effect have been had the turbulence been heavy?

[props2you]

This is bound to raise troubling questions about the corporate culture at AF. Here you seem to find similar errors as the YYZ incident.

The disaster began about 2½ hours into the Rio de Janerio-to-Paris flight, and about nine minutes after the captain, the senior of three pilots on board, left the cockpit for a routine rest period. He designated the junior of the two first officers as the “pilot flying.”

First the Air France pilots flew straight into a towering series of massive thunderstorms – the only flight that night on a South America-to-Europe route that didn’t divert around the dangerous weather.

Then the speed sensors apparently failed – possibly choked by ice crystals – and the autopilot clicked off. That’s a problem but hardly creates an unrecoverable emergency. It does, however, require the pilots to take control and “hand fly” the big Airbus A330, something supposedly practised routinely to keep pilots from becoming overly reliant on automation.

Instead, nose-high, the aircraft zoomed upward, reaching nearly 38,000 feet, its speed decreasing in the sudden climb, and the first of repeated “stall warnings” sounded. In aerodynamics, a stall is when airflow over the wings slows to the point where lift is lost. Recovery requires an immediate lowering of the nose.

Instead, the pilots inexplicably kept pulling back on controls, kept the nose angled up, and then – for more than three long minutes – allowed the aircraft to free fall nearly straight down until it smashed, wings level, engines racing and nose still inclined up, into the sea at nearly 200 kilometres an hour. All 228 people on board were killed...

...After the AF447 loss in mid-Atlantic, an outside safety study faulted the airline’s top management and pilot arrogance. “In general, there is an absence of strong safety leadership at all levels,” the study said, adding pilots were elitist and treated other Air France personnel “in an autocratic and arrogant manner...

http://www.theglobeandmail.com/news/world/europe/air-france-crash-pilots-fought-with-controls/article2037022/

[RGT2.0]

I have a feeling these pilots did not know they where in a stall.

Do 'they' train for stalls in large aircraft like this ....at any airline.

Airspeed awareness and how to recognize a bad situation seems to be a problem for a lot of pilots (airlines).

[DEFCON]

Crew experience or the lack thereof, training or the lack thereof, ability or the lack thereof, complex aircraft, long range flight, circadian rhythms, programmed rest periods, poor air quality, poor food quality, etc,.

The above represents a list of ‘negative factors’ that are stacked against you on most long haul flights before the aircraft even leaves the gate. Add the unexpected in and……

[Miles]

"Truly superior pilots are those who use their superior judgment to avoid those situations where they might have to use their superior skills."

[bm330]

Blame the Pilots of Air France 447? Not So Fast

The original mistake of entering severe weather gets the ball rolling but after that, there are many scenarios that become a nightmare for modern FBW aircraft.

It's possible for an unreliable speed scenario to have both an overspeed indicated on the speed tape and the stall protection system activated at the same time. With the interconnectivity of auto thrust sytems to flight envelope, power can roll off because it senses an overspeed even though AOA sensors sense a stall.

The magic in a 330 needs to be severly compromised for it to sustain a stall. The standard escape manouever is to pull the stick all the way aft and hold it - the aircraft climbs without stalling until clear of ground/windshear/... For the aircraft to remain in a stall would require a major failure of the flight computer system. The report states the 330 was doing 107kts at impact but doesn't say if that was based on sensed airspeed or groundspeed. For the aircraft not to self recover from a stall, it would either have thought it was still flying or not have any flight computers engaged.

[J.O.]

From reading the BEA's report (http://www.bea.aero/...7mai2011.en.pdf), I believe that the aircraft was in a deep stall condition. I am not convinced that the crew had enough information to fully understand the situation they were in, particularly in terms of the angle of attack.

At 2 h 10 min 51, the stall warning was triggered again. The thrust levers were positioned in the TO/GA detent and the PF maintained nose-up inputs. The recorded angle of attack, of around 6 degrees at the triggering of the stall warning, continued to increase. The trimmable horizontal stabilizer (THS) passed from 3 to 13 degrees nose-up in about 1 minute and remained in the latter position until the end of the flight.

The altitude was then about 35,000 ft, the angle of attack exceeded 40 degrees and the vertical speed was about -10,000 ft/min. The airplane's pitch attitude did not exceed 15 degrees and the engines' N1's were close to 100%. The airplane was subject to roll oscillations that sometimes reached 40 degrees. The PF made an input on the sidestick to the left and nose-up stops, which lasted about 30 seconds.

At 2 h 12 min 02, the PF said "I don't have any more indications", and the PNF said "we have no valid indications". At that moment, the thrust levers were in the IDLE detent and the engines' N1's were at 55%. Around fifteen seconds later, the PF made pitch-down inputs. In the following moments, the angle of attack decreased, the speeds became valid again and the stall warning sounded again.

At 2 h 13 min 32, the PF said "we're going to arrive at level one hundred". About fifteen seconds later, simultaneous inputs by both pilots on the sidesticks were recorded and the PF said "go ahead you have the controls".

The angle of attack, when it was valid, always remained above 35 degrees.

The recordings stopped at 2 h 14 min 28. The last recorded values were a vertical speed of -10,912 ft/min, a ground speed of 107 kt, pitch attitude of 16.2 degrees nose-up, roll angle of 5.3 degrees left and a magnetic heading of 270 degrees.

When the air data was lost, the aircraft would have entered the second level of alternate law (ALT 2). In this configuration, most of the normal law protections are lost, with the exception of load factor protection. Pitch, angle of attack, bank angle and low energy protections are all lost. With the stab trim at 13 degrees nose up, it would be very difficult to lower the nose enough to reduce the angle of attack to a "flyable" angle. Any increase in thrust would only serve to increase the pitch attitude and angle of attack.

I'm starting to think that the AOA based indicator mentioned by Rich would have been a great help to the crew in this difficult (and very rare) scenario.

[boestar]

There was a program on the CBC last night about "Why Did 447 Crash" While interesting the information now known on the CVR and FDR is missing and some of the inferences seem to be at odds with the interim report. However one thing that seemed plausable for thier entry into the storm was that the weather radar may have been returning hits from a much smaller cell directly in their path towards the 250 mile wide 50k feet high major cell. This would in effect block their "sight" of the larger cell until they had passed through the smaller cell and at that point it would be too late to turn around without entering the cell anyway.

I had never though of this before but the smaller cell would have been like trying to see through a wall since the raday will only return the closest water.