Timeline of Airbus speed data problems
June 6 (Reuters) - Air France was at odds with Airbus over the right way to respond to iced-up sensors affecting airspeed readings at high altitude, a potential problem for investigation in the crash of an A330 jet last week, according to the airline.
Here is a timeline of the search for a solution as set out by Air France. Airbus was not immediately available to comment.
Meanwhile regulatory filings show that flawed airspeed readings were causing concern as early as 2001 [ID:nL6511316].
Sept. 2007
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According to Air France, Airbus recommends operators of its short/medium-range A320 family change speed sensors, known as pitot probes, due to malfunctions. The optional recommendation also applies to long-haul aircraft with the same sensors.
Air France applies the recommendation to those A320s that have experienced a problem, but not to its A330/340 fleet.
May 2008
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Air France notices temporary loss of airspeed data lasting several minutes during cruise on A330/340 jets due to icing.
Air France presses Airbus for a solution. According to the airline, Airbus says using the same sensors recommended for the smaller A320 would not solve the problems witnessed at cruise height and reiterates established operating procedures.
Q1 2009
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Laboratory tests show the new sensor could after all reduce the icing problem at high altitude, according to Air France. It says Airbus then proposes an in-flight test to verify this.
April 27
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Air France decides not to wait for the test and starts installing new sensors on its 16 A330s and 19 A340s.
June 1
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Flight 447 disappears in the Atlantic during a storm.
June 4
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Airbus says it has issued advisory reminding crews of the procedures to follow in the absence of reliable airspeed.
June 5
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France's BEA says the investigation focuses on the storm and evidence of conflicting airspeed data but rules nothing out.
June 6
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BEA says the A330 sent out 24 error messages including one on airspeed discrepancies simliar to incidents seen on related aircraft, but says it is too early to speculate on the cause.
Airbus confirms it had recommended changing A330 speed sensors before the crash but does not say whether this refers to the Sept. 2007 note mentioned by Air France. A spokesman says this was a performance upgrade, not a mandatory safety measure.
Air France announces it has accelerated the replacement programme. It does not say whether the crashed A330 had new sensors nor what proportionate of its fleet has been upgraded.
(Reporting by Tim Hepher; editing by Michael Roddy)
