Air France 447: Report Shows Air Speed Sensors Likely Led to Crash

[RamboLiberal]

Source: ABC News

With two co-pilots at the helm, Air France Flight 447 went down into the Atlantic two years ago after speed sensors failed and the Airbus jet stalled, a German newspaper reported.

Der Spiegel cited sources who are familiar with the contents of flight recorders recovered from the ocean two weeks ago. The unnamed sources told the newspaper that the chief pilot, Captain Marc Dubois, had left the cockpit just before the Airbus A330's airspeed sensors failed four hours into the flight. The failure of the sensors caused the autopilot to disengage and the plane to stall, going into an uncontrolled dive.

The air speed sensors have long been suspected as the cause of the crash. Air France flight 447 was en route from Rio de Janeiro to Paris May 31, 2009, when it when down in the Atlantic Ocean, killing all 228 people aboard.

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Der Spiegel reported that the black boxes showed the Air France plane climbed sharply after the speed-sensor failure and Captain Dubois returned to the cockpit shortly before the crash. From another part of the plane, the captain had communicated with the cockpit on actions to save the aircraft, the newspaper said.



Read more: http://abcnews.go.com/Business/air-france-447-air-speed-sensors-eyed-crash/story?id=13663970

[Dreamer Tatum]

1. At least it wasn't a Boeing jet

...now we can be spared the reminders of how much the CEO makes.

[SoapBox]

2. This just makes me sick to my stomach...

...the carriers had been warned about those sensors, but, it was only a warning and not a mandated replacement, which it should have been.

So sickening and such a waste of life.

[Blue Owl]

3. Somewhat comforting they at least were able to identify the cause

Yet chilling that it happened.

[jberryhill]

4. Pretty good call on the original theory

And good to have confirmation.

[MilesColtrane]

5. I thought those pitot tubes had deicers.

[RamboLiberal]

6. Apparently problems in extreme temps/conditions

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That pitot tube performance standards do not meet real-world conditions has been known since the mid-1990s, according to a time line of incidents compiled by Arnoux. Those deficiencies—including blockage of the speed sensors due to icing—had triggered individual actions by regulators or manufacturers but no concerted effort to address shortfalls (see article below).

That is now changing. The BEA has called for a complete review of pitot tube certification standards and a scientific assessment of the meteorological conditions that cause problems.

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BEA officials first want to learn about the size and shape of ice crystals formed in the extremely cold high-altitude conditions, which can block pitot tubes and lead to erroneous speed information being provided to pilots and flight control systems. Currently, the probes are certified only to handle temperatures of up to -40C. EASA says climate change could be contributing to more extreme weather conditions at high altitudes that have not previously been encountered by aircraft.

Arnoux believes the BEA recommendations “do not go far enough.” If it cannot be demonstrated that pitot tubes can function despite large quantities of ice crystals at an altitude of 41,000 ft. and temperature of -70C without disruption, then operational changes need to be made, he argues. If the probes fail to meet that standard, then Airbus aircraft should “be limited to flying outside of clouds at these altitudes,” Arnoux says. Such a move would have huge operational implications for airlines on many long-range routes by reducing the efficiency of their Airbus wide-body fleets.

http://www.aviationweek.com/aw/generic/story_generic.jsp?channel=awst&id=news/awst/2010/01/04/AW_01_04_2010_p28-193411.xml&headline=A330%20Pitot%20Tube%20Icing%20Concerns%20Persist

[MilesColtrane]

7. Looks like a clear case of profit over safety.

Glad I was on a triple 7 instead of an A330 on my trip last November.

[October]

15. Always is.

Profit first.

[jimmil]

8. The flight crew just screwed up...

When you suspect or know of a malfunction in equipment the first thing you do is cross check it with other instruments. That is simple instrument training. If the pilot(s) would have done so maybe things would be different. Flying through bad weather is the captain's call and aircraft can in most cases fly safely through them. However, thunderstorms can have violent wind shears that can cause an airplane to loose control. It was the captain that made the decision to fly through the weather and it is his fault that this plane went down.

[Keith Bee]

10. That's pretty damn easy to say when you're sitting at a keyboard

I watch Mayday whenever possible, and faulty maintainence causes a lot more crashes than pilot error.

[Downwinder]

11. I disagree.

The pitot tubes have heating elements included in their design and normally these elements are sufficient to keep the inlets of the tubes free of ice. However, the pitot tube used on the Airbus A330-200 may have a design flaw that allows it to become encrusted with ice during encounters with heavy freezing precipitation.
http://www.designnews.com/article/278607-Airbus_Focuses_More_Closely_on_Flight_447_Pitot_Tube_Problems.php?rssid=20028

Try flying in coffin corner without airspeed indication and control feedback based on a computer which requires airspeed sensors to operate.

[CreekDog]

17. NOVA did a show on AF447 and even a year old, it's hypothesis has held up

The show is available on Netflix streaming. It may be on the PBS website as well.

I recommend watching it, they explain what they think were the sequence of events and how these appeared to the pilots.

[Crabby Appleton]

18. NOVA show on youtube in 4 parts

http://www.youtube.com/watch?v=BTL3WfpMOM0

[October]

13. Do some research on those pitot tubes on the A330 before you spout off

You sound like you know just enough to not know much. Perhaps you're a private pilot?

We're not talking about a Cessna 152 here -- it's a little more complex than you stated.

What a disgusting opinion -- but oh-so-revealing.

[October]

16. If Air France had installed the recommended replacement pitot tubes

we probably wouldn't be having this 'thread.'

But they (Air France) actually lobbied to have an airworthiness directive overturned -- said directive mandated the defective pitot tubes be changed.

[Nihil]

19. And *THAT* is the crux of the matter ...

> If Air France had installed the recommended replacement pitot tubes
> we probably wouldn't be having this 'thread.'
> But they (Air France) actually lobbied to have an airworthiness directive
> overturned -- said directive mandated the defective pitot tubes be changed.

Air France are the criminals here, not the flight crew, not the Airbus engineers.

[Blue_Tires]

9. well now we finally know...

I'm still unsure how the pilots were not able to stay in the air after a simple systems failure...Aren't there a lot of failsafes and redundancies built into the flight management software?

[RamboLiberal]

12. See Downwinder reply 11

Damn hard in those conditions - night, lack of horizon, faulty airspeed indications.

Pitot tube problems indicating air speed have caused several crashes from what I've read - especially at night.

And could the computer responded incorrectly?

Even more serious are the indications that the plane itself might have responded wrongly to the stall. "The data recorder indicates that the plane pulled steeply upwards shortly after the speed sensors failed," says an expert with ties to the investigative team, adding that this could have caused the plane to stall.

Of course, it's possible that the pilot misestimated his plane's speed and increased the engine thrust, thereby pulling up the nose. But it's also possible that onboard flight computers were responsible for the maneuver. The computers are designed to take control whenever the plane's computer deems it is in a threatening situation. A team of aerospace researchers observed similar behavior in a flight simulator a few months ago.

http://www.spiegel.de/international/europe/0,1518,764227,00.html

[October]

14. Not when pitot tubes are unable to feed the air data computer accurate information.

Can't operate when BOTH are out --

[Blue_Tires]

20. UPDATE: Black Boxes Point to Pilot Error

The pilots of an Air France jet that crashed into the Atlantic Ocean two years ago apparently became distracted with faulty airspeed indicators and failed to properly deal with other vital systems, including adjusting engine thrust, according to people familiar with preliminary findings from the plane's recorders.

The final moments inside the cockpit of the twin-engine Airbus A330, these people said, indicate the pilots seemingly were confused by alarms they received from various automated flight-control systems as the plane passed through some turbulence typical on the route from Rio de Janeiro to Paris. They also faced unexpectedly heavy icing at 35,000 feet. Such icing is renowned for making airspeed-indicators and other external sensors unreliable.

Ultimately, despite the fact that primary cockpit displays functioned normally, the crew failed to follow standard procedures to maintain or increase thrust and keep the aircraft's nose level, while trouble-shooting and waiting for the airspeed sensors and related functions to return to normal, according to these people.

Slated to be disclosed by investigators on Friday, the sequence of events captured on the recorders is expected to highlight that the jet slowed dangerously shortly after the autopilot disconnected. The pilots almost immediately faced the beginning of what became a series of automation failures or disconnects related to problems with the plane's airspeed sensors, these people said

http://online.wsj.com/article/SB10001424052702304066504576341631579541512.html?mod=googlenews_wsj

NOTE: So far the WSJ is the only major publication running with this...Every other outlet that has printed the same refers to the source WSJ story

[joshcryer]

22. NOVA showed that they got it right. With very little data. Amazing. Utterly amazing.

[October]

23. 13 other incidents... but now with the death of the crew they can find blame

Now Air France and Airbus can remain corporate buddies while blaming the pilots, per usual. They can put their fixes into place QUIETLY, and training will change, etc., but the crew will be blamed.

Utter bullshit.

[Blue_Tires]

21. fwiw here is a link to the discussion on a pilot's forum

http://www.airliners.net/aviation-forums/general_aviation/read.main/5149481/1

[October]

24. NOT a "pilots" forum - that's an aviation enthusiasts forum /nt

Enthusiasts, btw, include airline managment, community, air travelers, photographers, etc. HARDLY a professional pilots' forum.