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.
Air France Airbus - its last few minutes? >>
Airbus
crash: can a triple-redundant system give false readings?
>>
Airbus could be asked to ground long-range airliners
>>