GATINEAU, QC, Jan. 9, 2013 /CNW/ -The Transportation Safety Board of Canada (TSB) today released its
investigation report (A11W0144) into the collision with a building of a
de Havilland DHC-6-300 Twin Otter float plane on 22 September 2011 in
Yellowknife, Northwest Territories.
The Twin Otter was flying from a mining camp at Thor Lake, Northwest
Territories, to the Yellowknife float-plane base with 7 passengers and
2 pilots aboard. While attempting to land during gusty and variable
wind conditions, the aircraft bounced, then porpoised and landed hard
on the right float. The flight crew aborted the landing, and the
aircraft lifted off in a nose-high, right-wing-low attitude that
continued with a right turn towards the shore. The aircraft then struck
power lines and the side of a building before coming to rest in an
adjacent parking lot. The 2 pilots were fatally injured, 4 passengers
were seriously injured, and 3 passengers sustained minor injuries. The
aircraft was substantially damaged but there was no fire.
The investigation found that changes in airspeed and the gusty wind
conditions led to a bounced landing. The crew attempted a recovery,
initiating a go-around by raising the nose of the aircraft and applying
full power with the wing flaps fully extended. However, the Twin
Otter's aircraft flight manual cautions against raising the nose beyond
level flight attitude during a go-around with fully extended flaps, as
raising the nose too high might cause a rapid decrease in airspeed and
a possible aerodynamic stall. The aircraft lifted off the water with
its nose very high and the right wing low. In this configuration, the
aircraft could not accelerate or climb, and it collided with power
lines and a building.
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