Air France Flight 447
Investigation: Pilots Not Properly Trained to Fly the Airbus A330?
June 6, 2012 ABC News
The Airbus A330 has
one of the most sophisticated automated piloting systems in the airline
industry, but the 2009 crash of Air France Flight 447 has some experts saying
that the pilots weren't adequately trained to handle the plane in an emergency
situation, and that the plane's stall alarm system may have added to the crew's
confusion and contributed to the disaster.
 |
| An Air France Airbus A330 |
The crash, which
killed all 228 passengers and crew on board, is considered one of the worst --
and most mysterious -- aviation disasters in modern history. One theory for
what caused that Airbus A330 to go down is that the two co-pilots, led by
58-year-old Captain Marc Dubois, were not properly trained and depended too
heavily on the plane's autopilot system. That system disconnected at
high-altitude when a speed sensor, called a pitot tube, froze over, sending
inconsistent readings to the plane's computers.
Air France declined
ABC News' request for an interview, pending the July release of the final report
from France's investigation. But according to Bill Voss, the president and CEO
of the Flight Safety Foundation, Air France was so confident in the design of
the Airbus A330, the airline had not trained nor prepared its pilots for the
situation the crew of Flight 447 encountered the night of the crash.
"No one was
trained for high-altitude stall recovery in the cockpit," said Voss.
"It's not part of the normal training curriculum...this is something that
really has to be reformed globally. This is a really big deal."
Air France Flight 447
was en route from Rio de Janiero to Paris on May 31, 2009, for an overnight
trip, when it vanished. The plane crashed into the Atlantic Ocean in the early
morning hours of June 1, 2009 -- nearly four hours after take-off.
Black box tapes were
recovered from the wreckage two years later in April 2011 and, amazingly, still
worked. The tapes revealed that almost four hours into the flight, the plane
was 800 miles off the coast of Brazil, and Captain Dubois left the cockpit for
a scheduled nap. At the time, the plane was about to fly into a thunderstorm,
one that other flights that night had steered around.
Once in the storm,
the plane's pitot tube, a critical piece of equipment that tells the pilot the
aircraft's air speed, failed, likely from ice crystals forming on it, according
to BEA officials who inspected the wreckage. When the pitot tube fails, the
Airbus's automatic pilot system disengages, shifting control back to the pilot.
According to the
tapes, First Officer Cedric Bonin, a 32-year-old pilot who had fewer than 5,000
flight hours under his belt, was at the controls but had never been in this
situation before at high-altitude. Bonin made the fatal mistake of pulling the
plane's nose up, which caused it to go into a deep stall.
"It seems that
the pilots did not understand the situation and they were not aware that they
had stalled," said Jean-Paul Troadec, the director of BEA, the French
authority conducting the investigation into the Flight 447 crash.
When the Airbus A330
goes into a stall as severe as what happened to Flight 447, Voss said the
plane's computer rejects the data it's receiving, thinking the plane couldn't
possibly be flying in such a radical condition, and then shuts off the stall
alarm.
"The computer is
thinking 'this doesn't make any sense, we must be on the ground. We must be
parked at the gate or we would be dead,'" Voss said.
Airbus claims the
stall alarm on Flight 447 "was performing as designed," and said
there is rationale behind its design.
"If you get as
low as 60 knots, the stall warning will cut out by design, and we do that
because on landings and take-offs at a low air speed, when the angle of attack
is erratic and it may not be reliable, we cut that out so it would not distract
pilots during take-offs and landings," said Bill Bozin, the vice president
of safety and technical affairs at Airbus.
As co-pilot Cedric
Bonin pulled continuously up on the controls, the stall alarm sounded for 54
seconds straight. But as Flight 447 went deeper into its catastrophic stall,
the alarm cut in and out intermittently, the black box tapes revealed. The
stall warning was working as designed, but critics charge the pilots would have
been confused by the mixed signals.
The co-pilots called
frantically for help from the captain, the black box tapes showed, but it took
Dubois more than one minute to return to the cockpit.
"What's
happening?" Dubois is heard asking when he re-enters the cockpit.
"I don't know
what's happening," one co-pilot responded.
It was not until the
final three seconds before the plane hit the Atlantic that the pilots even
realized they were going to crash, the black box tapes revealed. Co-pilot David
Robert is heard on the tape recording saying, "Oh my God, we're going to
crash. I can't believe it." The last words on the recording are Bonin
saying, "But what's happening?"
Peter's Comment
If the stall
warning was designed to switch off automatically during lower than normal
stalling speed flight (deep stall) then it was an accident waiting to happen.
The pilots don’t
need a stall warning while the wheels are on the ground but they will certainly
need it at any time in flight when the angle of attack is critically high
regardless of speed. It is normal on modern airliners for the speed brakes,
once armed, to automatically deploy when the wheels touch the runway. In my
view, it follows that the stall alarm should only be silenced by the wheels
touching the runway rather than when the airspeed falls below normal stalling
speed.
And what of the
pitot head heating failure. That would have been turned on during routine
checks at the beginning of the flight and the pitot should not have iced up.
This indicates a technical failure rather than crew inexperience.
All too often
dead pilots are blamed for the shortcomings of others. This crew appears to
have been one of normal age and experience. I don’t think the same can be said
of the aircraft with regard to its design and/or maintenance.
