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118
passengers were on board British Midland
flight 92 when it departed London's
Heathrow airport bound for Belfast on the
evening on January 8, 1989. Captain Hunt
and his First Officer, along with six
other cabin crew members brought the total
on board the 737 to 126. Flight 92
departed just before 8pm and was promptly
cleared to FL350. Just after 8pm, while
passing through FL280, there was a loud
noise, the aircraft began to vibrate, and
light smoke entered the cabin area through
the air conditioning system. Passengers in
the rear of the aircraft reported seeing
flames coming from the port side engine.
On the flight deck, though the crew could
feel the vibrations and smell smoke, there
were no aural or visual warnings.
Wreckage of 92
Captain
Hunt disengaged the autopilot and took
control of the aircraft. There were no
anomalies in the engine indications, but
believing that the air conditioning
received bleed air from the right engine,
Hunt believed the difficulty was coming
from there. Hunt throttled back the right
engine and both the vibrations and the
smoke seemed to decrease. The First
Officer called London ATC to report the
emergency. Hunt initially ordered the
engine be shut down, but before it could
be done, Hunt decided that the engine
seemed to be running satisfactorily and to
keep it running. At this point, they were
only minutes away from Castle Donington
airport, which was British Midland's
maintenance facility, so Hunt decided to
divert there. Having made the decision to
divert and being cleared for a descent,
Hunt then advised the First Officer to
proceed with the shutdown of the starboard
engine.
The Captain then made
an announcement on the PA that he had shut
down the right engine and that they would
be landing shortly. Apparently none of the
passengers who saw flames from the left
engine either heard the captain or felt
that they were in position to say anything
about it. The aircraft descended normally
except for continued vibrations and the
crew intercepted the localizer for runway
27 at Castle Donington at 2,000ft and
began it's descent down the glideslope
just four miles from the runway.
At 900ft and 2.5 miles
from touchdown, the left engine completely
lost power. The captain called for a
relight on the right engine and several
seconds later, the engine fire lights came
on from the left engine. The Captain just
had time to call for emergency brace over
the PA before the aircraft impacted the
ground at 110kts, just three-quarters of a
mile from the runway. The aircraft bounced
off the embankment, went across a motorway
and into the other side of the embankment,
fracturing the fuselage and flipping the
tail section over. Thirty nine passengers
were killed in the impact and eight others
died later.
It's highly unlikely that both engines
would fail concurrently, so investigators
were very anxious to examine the wreckage
for clues as to what caused a total loss
of power on flight 92.
Both
engines suffered extensive impact damage
and a great deal of debris was lodged
inside the forward sections. Interior
inspection of the engines, however,
revealed major differences between the
condition of the two. The right engine
showed only ground impact damage and it
was clear that the engine was not running
at the time of the crash.
Wreckage of 92
The left engine,
however, showed severe fire damage and
several blade fragments were missing, some
recovered along the flight path as far
away as a mile and a half from the crash
site. It was clear that the left engine
had been the one which had suffered
mechanical difficulty during flight. So
what then would cause the crew to shut
down the good engine?
Recovery of the CVR and FDR showed that,
during the initial period of vibration and
smoke, there were large variations in N1
and EGT indications as well as low fuel
flow. When asked which engine was causing
trouble, the First Officer replied "It's
the le...it's the right one." The FDR
shows at this time that all right engine
indications were normal. The FDR also
showed that when the right throttle was
closed, the left engine indications
returned to near normal with the exception
of the fuel flow, which was still erratic.
Hunt attempted to discuss with the First
Officer what indications had been
received, but radio calls prevented them
from further examining their situation.
Further
study of the left engine showed that the
fire had occurred after the crash. The
initial cause of engine damage was the
fatigue failure of one of the fan blades
and further overload failure of the rest
of the blades. It was clear then that the
right engine was functional throughout the
flight and the crew had somehow
misidentified it.
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