RICHMOND, BC, July 31, 2013 /CNW/ - The Transportation Safety Board of
Canada today released its investigation report into the fatal October
2011 accident involving a Northern Thunderbird Air Beechcraft King Air
A100, which crashed just short of a runway at Vancouver International
The investigation found that during routine maintenance, the left
engine's oil reservoir cap remained unsecured, and that this was not
detected during the pre-flight inspection. During the climb-out, the
crew noticed oil leaking from the left engine and elected to divert the
flight back to Vancouver. While on the final approach, power was likely
applied only to the right engine, causing the pilot to lose control of
the aircraft as it rolled left, pitched down and crashed. Investigators
found that the aircraft's speed was below the speed needed to maintain
directional control with low power on the left engine and high power on
the right engine. The pilot reduced the right engine's power and
regained control; however, low altitude limited the recovery, and the
aircraft collided with the ground. The aircraft was destroyed in a
post-impact fire. All of the passengers were seriously injured, and
both pilots succumbed to their injuries in hospital.
The investigation found that a non-mandatory modification to limit the
loss of oil when the oil cap is left unsecured was not made to the
aircraft's engines. Additionally, multi-engine aircraft flight manuals
and training programs do not include cautions and minimum control
speeds for situations when one engine is at a low power setting and its
propeller is not feathered (blades placed parallel to airflow to reduce
drag). Operating below these unpublished speeds can lead to loss of
control of the aircraft.
The investigation concluded that this was a survivable accident.
However, a post-impact fire destroyed the aircraft, and the 2 pilots
died from burn-related injuries. In this accident, there was evidence
of live battery-powered circuits after impact, and fire in areas where
wiring is concentrated in the cockpit. More needs to be done to reduce
the risks associated with post-impact fires. The Board is therefore
concerned that if no action is taken by Transport Canada to address the
recommendations made in the TSB's 2006 Safety Issues Investigation on Post Impact Fires Resulting from
Small-Aircraft Accidents, ignition sources will remain, and the risk of post-impact fires will
Following the accident, Northern Thunderbird Air provided information to
its flight crews on the risk of flying with reduced power on one engine
as speed decreases, and amended its standard operating procedures to
reduce the risk of recurrence. Transport Canada is working with the
engine manufacturer to increase implementation of the modification to
limit oil loss from unsecured oil caps.
The TSB is an independent agency that investigates marine, pipeline,
railway and aviation transportation occurrences. Its sole aim is the
advancement of transportation safety. It is not the function of the
Board to assign fault or determine civil or criminal liability.
SOURCE: Transportation Safety Board of Canada
For further information:
Transportation Safety Board of Canada
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