Almost four years after an Air France-KLM Group plane crashed into the Atlantic killing 228 people, Airbus SAS, which built the ill-fated A330 jetliner, is still seeking ways to help pilots avoid a repeat occurrence.
With flight simulators unable to accurately replicate the conditions after an aircraft loses lift, or stalls, wholesale changes to training regimes may be required, according to Airbus test pilot Terry Lutz. Other solutions might include giving more control to computers even in the confused conditions under which command currently diverts to the human crew.
“The whole training philosophies need to be adjusted,” Lutz said in a presentation at the Royal Aeronautical Society in London. “It’s time for everybody to take a step back in the training environment and decide what things are absolutely crucial and need to be maintained year after year.”
Air France Flight 447 was lost en route from Rio de Janeiro to Paris on June 1, 2009, after its pilots took control when the autopilot disengaged in response to conflicting speed data later found to have been caused by iced-up sensors. A probe by French accident investigators said the crew lacked the training to respond to the surprise scenario and worsened the situation by opting to lift the plane’s nose in an attempt to gain altitude.
While work is under way across the industry to improve the models used to run simulators, until the feedback they provide is completely reliable their use could cause pilots to make poor decisions, said Stephane Vaux, an Airbus flight-test engineer.
The dynamic and varied flying conditions that follow a loss of lift are especially tough to replicate, according to Paul Bolds-Moorehead, a senior lead engineer at Boeing Co., who took part in a rare joint presentation with his Airbus counterparts.
“It has been extremely challenging to try and get an accurate simulator, post-stall,” he said.
Vaux, who also spoke at the event, added that low-altitude stalls are one area where understanding is particularly poor.
Engineers are also exploring whether a plane could be better protected after a stall by expanding the use of computer-generated responses even when control reverts to its pilots following the receipt of conflicting information, as happened in the Air France crash.
“Could we develop a way to provide some kind of angle-of-attack limiting function?” Bolds-Moorehead said. “It would be very problematic to do, but it’s something we should probably look into.”
Programming an aircraft to effectively recover itself has even been discussed at a “philosophical level,” though Boeing’s mantra remains to leave the pilot in charge, he said.
Air-safety officials are studying whether increased cockpit automation has actually caused basic flying skills to atrophy. The crew of a Colgan Air turboprop that crashed near Buffalo, New York, in 2009 also failed to properly deal with a stall, the U.S. National Transportation Safety Board has found.
When a plane loses lift its fate will ultimately be determined by the willingness of its pilots to push down the nose and force more air over the wings to regain control, even though that action might seem counterintuitive with altitude being lost, said Van Chaney, Boeing’s deputy chief test pilot.
“You have to be willing to give up thousands of feet of altitude to break stall,” he said at the London presentation.
Airbus has said the A330 in the AF447 crash was responsive throughout its descent into the sea. Air France has defended its pilots, saying confusing cockpit readouts were partly to blame.