As ships and aircraft search thousands of square miles for a missing
Malaysian Airlines jetliner, officials are trying to understand how the
Boeing 777 could have apparently dropped out of the sky without warning
or distress signal.
The mysterious lack of contact and the fact that the plane disappeared
from radar midflight is so rare that it brings to mind only one other
plane disaster in recent years, the doomed 2009 Air France flight 447.
The Air France flight, an Airbus A330, from Rio de Janeiro to Paris
crashed in the Atlantic midway through the flight without sending a
distress signal. All 228 aboard were killed.
It took three years for investigators to piece together what led to the
crash, with two years spent just trying to find the black box data
recorders on board. In 2012 the French government's official accident
investigators, the BEA, released their final report, which found that
the flight crashed due to a combination of technical failures and pilot
error.
The BEA found that a speed sensor on board the plane, called a pitot
tube, stopped functioning after becoming clogged with ice at
high-altitude while the plane was flying through a thunderstorm.
As a result, the auto-pilot disengaged and shifted the controls back to
the pilots. As they flew in heavy turbulence the Air France pilots
failed to properly diagnose the severity of the problem because the
pitot tube, a critical piece of equipment to the aircraft, was sending
inaccurate data to the cockpit, the report said.
"Despite these persistent symptoms, the crew never understood that they
were stalling and consequently never applied a recovery maneuver," the
2012 report said.
When the auto-pilot was disengaged, a co-pilot pulled the nose of the
plane, which led to aerodynamic stall. From the first stall warning at
2:10 a.m. to when the plane crashed four minutes later, the pilots never
sent a distress signal as they frantically tried to save the plane.
According to the black box recordings, the pilots appeared unaware they
were going to crash until the final seconds before hitting the water.
"Our investigation is a no-blame investigation. It is just a safety
investigation," Jean-Paul Troadec, the director of BEA, told ABC News in
a 2012 interview. "What appears in the crew behavior is that most
probably, a different crew would have done the same action. So, we
cannot blame this crew.
What we can say is that most probably this crew
and most crews were not prepared to face such an event."
ABC News' Matt Hosford, Lauren Effron and Nikki Batiste contributed to this report
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