The Transportation Safety Board of Canada (TSB) released its investigation report into the 22 September 2011 crash of a DHC-6 Twin Otter float plane, operated by Arctic Sunwest Charters, in Yellowknife, NT, Canada. The crash was caused by a loss of control during a go-around following a bounced landing in gusty wind conditions.
The airplane had departed from Thor Lake, NT on a flight to the Yellowknife Waterdome. There were seven passengers and two crew members on board.
The first officerwas acting as the pilot flying.
Due to the 2 to 3-foot waves (rollers) on the destination lake, the crew planned their approach so as to land close to the shore and to avoid entering the passage between the shore and Jolliffe Island. The captain also advised that the airspeed should be kept above 80 knots indicated airspeed (KIAS), which is 10 KIAS above the normal approach speed of 70 KIAS, for the full-flap (37.5°) approach and landing. During the approach, the captain cautioned the FO twice about the airspeed getting too low. The aircraft touched down in the intended landing area and bounced, then contacted the water a second time with the right float first. The float dug in, and the aircraft yawed to the right, turning towards the shore.
Without declaring that he was taking control, the captain placed his right hand on the power lever over the FO’s left hand and initiated full power for a go-around. The float plane lifted off in a nose-high, right-wing-low attitude, in a right turn that continued at a low altitude over the shore and toward the buildings in Old Town, Yellowknife. At this time, the captain called for the flaps to be raised to 20°, to which the FO responded. However, the flaps were not moved before impact. The right wing contacted power lines, causing the aircraft to rotate to a nose-down attitude. The bottom of the floats then contacted the side of a 3-storey office building. C-GARW dropped to the ground on its nose section, then cart-wheeled to its left into an adjacent parking lot. The stall warning intermittently activated throughout the go-around until just prior to impact.
Both pilots were killed and five of the seven passengers were injured.
TSB reported the following findings as to causes and contributing factors:
- Airspeed fluctuations at touchdown, coupled with gusty wind conditions, caused a bounced landing.
- Improper go-around techniques during the recovery from the bounced landing resulted in a loss of control.
- It is possible that confused crew coordination during the attempted go-around contributed to the loss of control.