On first reading the release of a factual ‘note’ on the last minutes of Air France flight AF447 on June 1, 2009 point to serious and persistent errors by the pilots of the Airbus A330-200 in which all 228 people on board died when it crashed into the mid Atlantic ocean on its way from Rio de Janeiro to Paris.
But that is not how some A330 pilots who have read the note see it, nor how the French investigators see it either.
What the factual note details is the an airliner suddenly and steeply climbing from a cruise altitude of 35,000 feet to 38,000 feet amid stall warnings and then plummeting for three minutes 30 seconds with its engines variously set at maximum thrust or idle power while it rolled steeply to the left and right by up to 40 degrees, finally hitting the ocean surface nose high (at 16.2 degrees) at a low ground speed of 107 knots.
The full note in English can be found here. It includes extracts from the cockpit voice recorder that indicate some confused moments on the flight deck.
The crash was preceded by a loss of airspeed values from the external speed and air pressure measuring pitot tubes, as established much earlier in the investigation.
The note also emphasises that most of the pilot inputs were to keep the nose of the jet high, a line that can easily be read to mean that the pilots persisted with the wrong response to the stall warnings until the jet slammed onto the ocean surface in a high G force belly flop.
The problem with the ‘note’ that A330 pilots have been quick to identify is that it is ‘selective’ in the information that it has released and raises questions as to what the instruments were really telling them, and is silent as to the warning messages the pilots would have seen on their flight displays or other factors that may have caused them to misread the nature of their predicament.
However the preamble to the note says as much:
This note describes in a factual manner the chain of events that led to the accident and presents newly established facts. The initial analyses will be developed in a further interim report that is scheduled to be published towards the end of July.
Only after long and detailed investigative work will the causes of the accident be determined and safety recommendations issued, this being the main mission of the BEA. The latter will be included in the final report.
The note further isolates the pilots in that it says the A330 responded fully to pilot inputs to the control surfaces and engine power settings.
However flight standards and pilot performance are ultimately the responsibility of Air France, which together with Airbus, is under investigation by a French public prosecutor for possible charges of involuntary manslaughter because of the crash.