Two Air France pilots have challenged Airbus and the French air crash investigators to face up to critical factors in the June 1 crash of flight AF447 in the mid-Atlantic, which killed all 228 people on board.

In an alternative report on the accident, they charge Airbus, the maker of the A330-200 that crashed, with recommending emergency procedures that were “at best confusing, at worst dangerous” if the jet experienced unreliable air speed readings.

They also say the “unchallengeable truth” is that if the airliner’s pitot tubes (external air-speed measuring devices) had not failed in the icing conditions the flight experienced, it would not have crashed.

And in their third major point, the pilots say that AF 447 relied on day old weather data that resulted in its flight crew plotting a course that went into the thick of a severe belt of tropical thunderstorms, which could have been avoided had more recent and available information been used.

These points contradict the interim report by the French crash investigation or touch on areas it hasn’t, as yet, addressed.

The report was sponsored by the Air France pilot union, the SPAF, and co-written by its president, a senior captain with the airline.

English media reports such as this from the London Daily Telegraph appear to have been written without reference to the detailed document and its sub sections, in French, the most critical of which (la perte au l’incoherence des vitesses) deals with the inadequacy of the Airbus and regulatory response to two very serious similar incidents involving Air Caraibes A330 flights the previous year, in which the pilots maintained control of their jets.

Since the disaster, Airbus has refused to discuss the criticisms of its procedures, and two other high-profile reports of pitot air-speed failings have been reported by America’s FAA involving a Delta A330 over the north Pacific and another mid-Atlantic incident involving Brazilian carrier TAM.

The AF447 crash investigation has been hampered by the non-recovery of the two flight recorders, which could have provided a record of the cockpit conversations and aural warning messages and precise performance information.

However, a worldwide directive has since been made requiring all A330 operators using the Thales pitot tubes made in France to replace at least two of the three units used on this type of jet with US made BF Goodrich pitots, which are installed on all Qantas A330s.

The interim report found that AF447 appeared to have been intact and pointed straight ahead when it crashed belly first onto the surface of the sea with sufficient force to drive the floor of the cabin upwards.

Automated service messages received by Air France indicated that its pitots had iced up before the crash. The storm cells in the area in which it came down were considered sufficiently strong to pose a severe hazard to an airliner.

Civil proceedings, which could lead to charges and damages against Air France, Airbus and Thales, have also begun in Paris.