The Transportation Safety Board (TSB) of Canada concluded that damage from a prior incident caused a DHC-3T float plane loss of control accident in the Northwest Territories (NWT).
On 22 August 2013, at approximately 18:50, a float-equipped Transwest Air DHC-3 turbine-powered Otter left Scott Lake, NWT, on a flight to Ivanhoe Lake, NWT. The aircraft did not arrive at the destination and was reported overdue. The wreckage was located on 23 August 2013, in an un-named lake 10 nautical miles north of the last-reported position. The pilot, the only person aboard, was fatally injured and the aircraft was destroyed.
An investigation revealed that during the approach to landing on the previous flight, the right wing was damaged by impact with several trees and that the damage was not evaluated or inspected by qualified personnel prior to the subsequent takeoff. The investigation also revealed that a number of stressors throughout the day disrupted the pilot’s processing of safety-critical information, and likely contributed to an unsafe decision to depart and operate a damaged, uninspected aircraft. En route, the damaged aircraft departed controlled flight likely due to interference between parts of the failing wingtip acting under air loads, and the right aileron.
To enhance safety in its operations, Transwest Air Limited held discussions with its pilots concerning pilots’ responsibilities to remove themselves from flight duty if they do not feel fit to fly. A Safety Directive was also issued outlining Transwest Air’s expectation of compliance with the Canadian Aviation Regulations and action to be taken in the event that an aircraft is damaged.
In November of 2014, the TSB announced that it would conduct a Safety Issues Investigation into Canadian air taxi operations to understand the risks that persist in this sector. The study will engage industry, the regulator and other stakeholders to gain a full understanding of the issues affecting air taxi operations.