Air France FDR data show aircraft remained stalled in final minutes of flight

By Perry Flint | May 27, 2011

Flight path of AF447. Photo: Courtesy, BEA.

Air France 447 took less than four minutes to fall from approximately 38,000 ft. into the waters of the South Atlantic following the disengagement of the autopilot on the Airbus A330-200, according to an interim report released by the French Air Accident Investigation Bureau (BEA) Friday that is based on CVR and FDR analysis (ATW Daily News, May 17).

BEA stated that following disengagement of the autopilot and autothrust, which apparently occurred after an "inconsistency between the speeds displayed on the left side primary flight display and the integrated standby instrument system" that "lasted for less than one minute," the aircraft climbed to 38,000 ft.; the stall warning was triggered and the airplane stalled. After taking command of the aircraft, "the inputs made by the pilot flying were mainly nose-up," and the aircraft remained stalled during the 3 min. 30 sec. it took to fall to the ocean. "The angle of attack increased and remained above 35 degrees. The engines were operated and always responded to crew commands."

According to the report, the captain was taking a scheduled rest at the onset of the crisis, which began approximately 2 hr. 10 min. 5 sec. into the flight. Around 10 seconds later the pilot not flying said, "So we've lost the speeds," and then "alternate law…" Under alternate or direct law, angle of attack protections are no longer available, BEA noted, but "a stall warning is triggered when the greatest of the valid [AOA] values exceeds a certain threshold."

The captain re-entered the cockpit approximately 90 sec. after the autopilot disengaged but the airplane never was stabilized. The recording stopped at 2 hr. 14 min. 28 sec. 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.

Discuss this news 13

27 May16:43

This sounds kind of like what

By Anonymous

This sounds kind of like what happened on AF296. Again, the pilots tried to take the plane out of danger, but the computer wouldn't let them.

28 May01:34

The BEA update states that

By Ralph

The BEA update states that angle of attack infomation is not presented to pilots. If the engines were operating normaly would the pilots be able to judge a safe AOA by reference to the thrust settings and the artificial horizon even if the speed info was absent or unreliable?

28 May08:08

I'm sorry Anonymous but

By Logic

I'm sorry Anonymous but that's rubbish. If you read the report you will see that the pilot flying made nose up inputs almost the whole time (contrary to standard procedure). Nothing to do with 'computers not letting them do anything'.
This is seems like a case of the pilots getting confused and mistakes. A very different situation from evil computers not letting them fly the plane.

28 May13:07

Good grief.....please know

By Anonymous

Good grief.....please know what you are talking about before making a comment like the one above.
A/P off and in alternate law....there is nothing preventing you from flying this a/c out of a stall.

Too many years of sitting uneventfully at cruise with your feet up does little to prepare you for such an event . More training re aircraft handling, particularily for long haul overseas pilots, is what will come out of this investigation.

28 May18:58

What will also come out of

By Retired after 40 yrs.

What will also come out of this will be the improper and incomplete training on the effective use of weather radar.
These guys got caught (like we all have) and instead of retreating and taking the long way 'round (the line of CB's), they persevered and tried to pick their way through. From the look of the wx satalite overlay....NO pilot should have ever been there...end of story.
When the BEA report is complete, I fear this will turn out very badly for a proud carrier and it's good pilots. ......but passengers have the right to believe that they are in the hands of well trained pilots in all situations.

28 May20:18

Okay, I'm sorry about the

By Anonymous

Okay, I'm sorry about the misguided comment. I guess I just misinterpreted the article. You don't have to attack me just because I made such a misguided statement. The pilots were definitely stupid in disengaging the autopilot. Since they were making so many mistakes, they were unable to retake control of the plane. So therefore, pilot error would be the primary cause of this accident.

29 May00:20

No it doesn't. Not at all.

By Tom M.

No it doesn't. Not at all. This article says pretty much the opposite. Pilot pulled nose up, resulting in a stall. There is no mention of a computer induced control movement. The pilots had 'control' of the aircraft.

29 May02:34

Anonymous please stop with

By TZ

Anonymous please stop with stupid comments. You obvioudly have no idea what are you talking about and you comments are totally out of balance. Read again. As far as cause is concerned, mature aviation professionals let the investigators state causes and never comment beforehand ( rightor wrong)

29 May05:16

I wish people would refrain

By Aotearoa

I wish people would refrain from making statements like "the pilots were definitely stupid in disengaging the autopilot". Please ask questions if you are unsure about aircraft systems......The autpilot disengaged as the a/c transitioned from normal law into alternate law, as it was designed to do!

If you want to make statements, please go to the BEA website and read the report....this isn't hard.

29 May08:35

For me the worst thing is the

By Anonymous

For me the worst thing is the disrespectful way the BEA is conducting this whole investigation. It is evident the political manipulation from the begining what it is a big sin in accident investigation. The BEA lost their reputation with the aviation world. I wish we had an investigation by ICAO in why the French are manipulating information. They are trying to delay more conclusions. They don't want people to talk about during the Paris Air Show.

29 May11:27

Actually Anonymous it was the

By Retired after 40 yrs.

Actually Anonymous it was the airspeed discrepencies caused by the pitot tube icing that disengaged the autopilot and autothrust....not the pilots. They had a whole lot on their plate as other systems started to shut down with the lack of airspeed information.

At this point the flight to Paris was over and it was time to descend out 38,000 ft (coffin corner where the difference between stall and overspeed can be as little as 30 knots), turn 180 deg. and head for an alternate somewhere in SA. The extreme turbulence that they may have been encountering at this point no doubt made the situation even worse.

The point here is that this airliner was put in harms way. Proper circumnavigation around the tropical storm in the first place would have prevented this story from ever seeing the light of day.

30 May02:27

The autopilot has been

By Anonymous

The autopilot has been disengaged automatically (not by the pilot). Don't comment if you don't know!

30 May02:32

Exactly! That's what we

By Anonymous

Exactly! That's what we should hear from everybody.