Angry pilots say Air France crash inquiry shields Airbus

French air crash investigators were accused yesterday of "protecting" Airbus after it emerged that implicit criticism of the plane-maker was sliced from last week's report on the Rio-Paris disaster.

The largest Air France pilots' union withdrew from the official investigation saying it had turned into a "one-sided" prosecution of the crew of the Airbus A330 which plunged into the south Atlantic on 1 June 2009.

It was confirmed yesterday that the French air accident investigation agency, the Bureau d'enquêtes et d'analyses (BEA), had removed from its report at the last moment a "recommendation" that the "stall" warning on Airbus A330 aircraft should be improved or replaced.

It was reportedly known long before the crash that "stall" warnings on some jets could confuse cockpit crews by sounding when there was no problem.

Last Friday's interim BEA report pointed to the failure of the pilots to respond to repeated audio and visual warnings that their plane was about to "stall" – or lose sufficient "lift" to keep it in the air. The jet dived for three and a half minutes towards the ocean with "stall" warnings sounding, but the pilots made no mention of this fact in their tape-recorded conversations. All 228 passengers and crew were killed.

Air France, which is in a battle with Airbus to avoid the legal and financial consequences of the crash, claims that the pilots may have been confused, given previous experiences with faulty alarm warnings. According to one airline source, the stall alarm would sometimes sound while a message would appear on pilots' screens telling them to ignore the "superfluous" warning. Airbus says that it had received no "precise" reports of faults of this kind.

The BEA admitted yesterday that it had removed, at a late stage, a recommendation on stall alarms from its interim report. The change was made, it said, because it was felt that "further work was needed" on this part of the investigation. A recommendation on Airbus stall alarms would be issued in the near future, the BEA said.

Air France, pilots' unions and a support group for victims' families are indignant that an official report should have been issued last Friday including strong implicit criticism of the performance of the pilots but no mention of the faulty "stall alarms".

Entraide et Solidarité AF447, an association of French victims' families, has been protesting for weeks against what it sees as BEA's determination to pin the blame on the three dead pilots. The president of the association, Robert Soulas, said yesterday the belated cut in last week's report "definitively discredits the investigation".

"We have now the proof that the suggestions (that pilots were to blame) coming from the BEA were premature, biased... and skewed towards defending Airbus," he said.

Air France and Airbus have been placed under formal criminal investigation for the "manslaughter" of the passengers and crew of Flight AF447. The final BEA report is expected this autumn but the criminal investigation may continue for many more months.