French authorities will tomorrow [2 July 2009] give an interim statement on their investigation into the loss of...
an Air France Airbus off Brazil on 1 June 2009.
They are expected to report that unreliable and conflicting speed data from the onboard electronics were important factors in the accident, which killed 228 people.
The statement will be issued by the Bureau d'Enquêtes et d'Analyses, the French accident investigation agency.
If the sensors and onboard systems prove to be a major factor in confusing the pilots - as happened in the fatal crashes of Birgenair 301 and Aeroperu 603 - it will raise questions in the safety-critical software community.
One question is whether new technology, which has generally improved air safety, can leave pilots bewildered, overwhelmed and even blind to what is really happening when there are multiple electronic failures.
After the release of tomorrow's statement Airbus may face calls to ground its worldwide fleet of long-range airliners, according to The Times.
It reports that the European Aviation Safety Agency (EASA) is likely to be asked why it had not taken action to remedy trouble that was well known with the Airbus 330 and 340 series. Nearly 1,000 of the aircraft are flying and until the loss of the Air France Airbus, Flight AF447, no passenger had been killed in one.
James Healy-Pratt of Stewarts Law in London, which represents the families of 20 of the victims of flight 447, said: "EASA has a legal and moral obligation to get to the bottom of this problem now. If there is a defective system and the aircraft is unsafe then it should be grounded".
French officials have already indicated that blocked pitot tubes might have fed unreliable information on air speed to the onboard systems which could have given the pilots conflicting information and warnings in the minutes before the aircraft went into the Atlantic Ocean.
Computer Weekly reported last month that investigations into the fatal crashes of two Boeing 757s in 1996 found blockages in the pitot-static systems. The cockpit voice recorders recovered from the two aircraft show that the pilots were confused by conflicting information from their cockpit displays, and a bewildering array of warnings that they were flying too fast and too slow.
A possible scenario in the minutes before the crash of AF447 is that the auto-pilot computer disengaged when it received unreliable information from the pitot sensors. The pilots might then have been left to fly the aircraft in a thunderstorm without the auto-pilot, and without faith in their instrumentation and onboard systems.