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Тема : Preliminaty report Air India crash - Ful switches targeted
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Fuel to Air India Plane Was Cut Off Before Deadly Crash, Report Says
A focus on the Boeing 787`s fuel switches in a preliminary
assessment raised questions about the pilotsТ actions, but much is still
unknown about Flight 171.
Seconds after takeoff and moments before an Air India flight crashed
last month, the fuel was cut off to both engines of the plane,
investigators said early on Saturday, in a preliminary assessment of information
from the Boeing 787Тs voice and data recorders.
The narrowed focus on the fuel switches on Air India Flight 171
raised questions about the pilots` actions and appeared to rule out
mechanical failure or design flaws. The report said there are no recommended
actions to the aircraft and engine manufacturers, Boeing and General
Electric.
In the cockpit voice recording, one of the pilots is heard asking
the other why did he cut off the fuel, said the report, by India`s
Aircraft Accident Investigation Bureau. The other pilot responded that he did
not do so.
The London-bound plane went down on June 12, about 30 seconds after
takeoff from Sardar Vallabhbhai Patel International Airport in the western
Indian city of Ahmedabad. All but one of the 242 people aboard were
killed.
The plane rammed into the dining hall of a medical college before
exploding in flames. Altogether, more than 270 people were killed, including
dozens on the ground, officials said. It was India`s worst aviation
disaster since 1996.
The supply of fuel to the engine is controlled by two switches in
the flight deck. Starting about 10 seconds after the fuel was cut off
on Flight 171, the data recorder shows, the switches were moved to
turn the fuel back on. But the plane could not gain power quickly
enough to stop its descent.
Each switch is equipped with a locking mechanism that is supposed
to prevent accidental movement, experts said. To turn the fuel supply
on, the switch must be pulled outward and then moved to a УRUNФ
position, where it is released and settles back into a locked position. To
turn the fuel supply off, the switch must be pulled outward again, moved
to the УCUTOFFФ position and then released again.
According to the report, the fuel control switches were turned off
one after another about a second apart, and the aircraft started to
lose altitude before crossing the airport perimeter wall.
Safety experts said it appeared unlikely that the switches were
moved without human involvement, whether intentional or accidental.
The fuel switches have safeguards built around them to avoid any
accidental switching off, said Shawn Pruchnicki, a former airline accident
investigator and aviation expert at Ohio State University.
For example, on the 787 and probably more airliners these days, the
switches themselves "you can`t shut them off without actually lifting them
up", he said. "So there`s a little mechanical gate built into the switch
you have to lift it up over this little gate. So you canТt just bump
it."
The flight`s captain was Sumeet Sabharwal, who had over 15,000 hours
of flying experience, while First Officer Clive Kunder brought 3,400
hours of flying experience, Air India said. That is more experience than
officials attributed to the pilots last month, when they estimated a combined
experience of about 10,000 hours.
India`s Aircraft Accident Investigation Bureau, the U.S. National
Transportation Safety Board and Boeing have been trying to determine what caused
Flight 171 to crash. The cockpit voice recorder and the flight data
recorder, usually referred to as the black boxes, were recovered from the
debris.
Although there was initial concern that the devices might have been
damaged in the extreme heat of the fire, investigating teams managed to
retrieve data from the boxes.
Video filmed by residents in nearby homes, as well as CCTV footage,
show the plane struggling to gain lift immediately after taking off. A
New York Times analysis of photos and videos suggested that the plane
might have experienced a catastrophic loss of hydraulic, electrical or
engine power. It could take months, possibly years, to reach definitive
conclusions. But as a member of the International Civil Aviation Organization,
India was obliged to submit a preliminary investigative report within 30
days of the crash.
The preliminary report was inconclusive, and said the investigators
will continue to Уreview and examineФ further evidence.
It appeared to rule out one theory floated by experts, of fuel
contamination. The report said a very limited amount of fuel could be retrieved
from the aircraft, which exploded into flames, and tests on those samples
would continue. But lab tests on samples taken from the bowsers and tanks
used to refuel the aircraftФ had found the fuel satisfactory.
The report not recommending any action to the aircraft and engine
manufacturers, three weeks after data was decoded, was seen by experts as an
indication of no obvious sign of mechanical failure or design flaws. That
would have prompted urgent communication to manufacturers to check other
aircraft.
The report, however, noted that the Federal Aviation Administration
had issued a bulletin in 2018 recommending that airlines inspect the
switches on the 787 and other jets amid reports that some may have been
installed with the locking mechanism disengaged.
But the F.A.A. did not rule that to be an unsafe condition at the
time, the report said. The switches on the Air India plane were replaced
by 2023, with no defects reported since. And, by that time, the
manufacturer would have almost certainly inspected the part to ensure the locking
mechanism was engaged, said John Cox, a former airline pilot and chief
executive of Safety Operating Systems, a consulting firm.
In a statement, Air India said it had received the preliminary
report but could not comment on specific details mentioned given the active
nature of the investigation.
The crash brought scrutiny not only to Boeing, but also to Air
India, the country`s oldest carrier, which was acquired by Tata Group after
half a century as a state-owned enterprise. The crash occurred just as
Air India was trying to pitch itself as a modernizing carrier.
The airline`s last major crash was in 2020, when a passenger plane
operated by Air India Express, a subsidiary, skidded and cracked in two on
a rain-soaked runway, killing at least 17 people in the southern
Indian state of Kerala. In 2010, an Air India Express plane overshot a
hilltop runway in Mangalore, in the western state of Karnataka, killing more
than 150 people.
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