Page 24 - AAA NOVEMBER - DECEMBER 2016 Online Magazine

FEATURE AVIATION SAFETY

Safer Skies

Despite recent accidents in commercial aviation, safety is the highest priority
By Atul Chandra

COMMERCIAL AVIATION REMAINS ONE
of the safest modes of travel and has
remained so because of robust regulations
and the highest importance given to the
safety of passengers travelling on board
an aircraft by regulatory agencies, national
authorities and of course the airlines and
maintenance agencies themselves. The
major causes of aircraft accidents per the
International Air Transport Association
(IATA) and areas of focus for the organisation
in 2015 were runway excursions (RE), loss
of control in flight (LOC-I), and controlled
flight into terrain (CFIT). In the period
from 2011 to 2015, the main source of hull
losses during that period were runway and its initial findings. According to the NTSB, autobrake application and extending the
taxiway excursions, which lead to a hull loss the uncontained failure of the right engine auto speed brakes, the aircraft rapidly
in 25 percent of all such events. The most occurred when the Boeing 767-300 (N345AN) decelerated, coming to a stop about 25
frequent categories of accidents in 2015 was approximately 6,550 feet from runway seconds after the throttle reduction. Because
were hard landings (24 percent) and runway 28R threshold. “Preliminary FDR data show of the uncontained engine failure, a fuel leak
excursions (22 percent). Hard landings may that the right engine failure occurred at an started a pool fire under the right wing. Engine
cause aircraft damage but do not typically airspeed of about 128 knots with the engine fragments were found as far as 800 metres
result in serious injuries to passengers and operating at takeoff power,” the NTSB report away from the accident site. The NTSB has
the same is the case of runway excursions. says, adding that the aircraft came to a full determined, “The right engine stage 2 high
Two recent jetliner accidents have again stop about 9,225 feet from the runway 28R pressure turbine disk fractured into at least
highlighted the fine line that exists between threshold. The pilots responded immediately 4 pieces (locations A, B, C, and D on image).
airline safety and disaster. to the incident and according to the data One piece went through the inboard section
gathered by the NTSB, ‘Approximately two of the right wing, over the fuselage and into
Uncontained Engine Failure on seconds after the engine failure, the left and a UPS warehouse facility (location A).” The
American Airlines Flight 383 right engine throttle lever angles decreased engine disk at the time of the accident had
The U.S. National Transportation Safety rapidly, when the airspeed was about 134 completed 10,984 cycles out of its life limit of
Board (NTSB) is presently conducting an knots.’ With the crew applying maximum 15,000 cycles. The GE CF6-80C2 engine family
ongoing investigation into the reasons
behind the uncontained engine failure of
a GE CF6-80C2B6 engine on an American
Airlines Boeing 767-300. Despite the
potential catastrophe of an uncontained
engine failure on a large jet engine, with the ABOVE: The uncontained
engine failure that occurred in
possibility of engine fragments penetrating the right GE CF6-80C2B6 engine
the aircraft cabin or severing vital controls; on American Airlines Flight 383
such events have been relatively few in resulted in engine fragments
nature. The accident took place on October being found half a mile away
from the accident site
28, when American Airlines Flight 383 with
170 souls on board (161 passengers and nine LEFT: One piece of the
crewmembers) commenced its take-off roll fractured turbine disk went
at Chicago O’Hare International Airport. through the inboard section
of the right wing, over the
In an investigative update released within fuselage and into a UPS
a week of the incident, the NTSB outlined warehouse facility
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