Low speed and high takeoff weight contributed to wing stall in August 2014 collision with water on Chantslar Lake, British Columbia
Richmond, British Columbia, 14 July 2016 – The Transportation Safety Board of Canada (TSB) today released its investigation report (A14P0132) into the accident in August 2014 in which an Air Tractor AT 802A Fire Boss Amphibian stalled on takeoff and crashed into Chantslar Lake, British Columbia. The pilot received minor injuries and the aircraft was substantially damaged.
On 14 August 2014, the Air Tractor, operating as Tanker 685, was carrying out wildfire management operations during daylight near Chantslar Lake. It was in a group of three similar aircraft working in formation, and was second in line for the touch-and-go runs to scoop water from the lake. On one of Tanker 685’s scooping runs, control was lost during liftoff, and the aircraft’s right wing struck the water. The floats then struck the water and separated from the fuselage as the aircraft yawed 270 degrees to the right. The aircraft remained upright and slowly sank. The pilot exited the cockpit and inflated the personal flotation device being worn. The fourth aircraft jettisoned its load, rejected its takeoff, and taxied to pick up the pilot who had been slightly injured.
The investigation found that a wing stalled, either independently or in combination with an encounter with a wing-tip vortex generated by the lead aircraft. This caused a loss of control moments after liftoff and resulted in both the right-hand wing tip contacting the water and a subsequent water-loop.
The takeoff procedure used, with the aircraft being heavy, its speed below the published power-off stall speed and a high angle-of-attack, contributed to loss of control at an altitude insufficient to permit a recovery.
The investigation also identified that, if takeoff procedures do not specify a liftoff speed, pilots may take advantage of engine power and pitch control capability to get airborne below the published stall speed and risk losing control at an altitude insufficient to permit a recovery. Also, if the aircraft is operated outside of the demonstrated flight envelope, there is a risk pilots will be exposed to aircraft performance for which they are not prepared.
The investigation also found that, even though a safety management system (SMS) and processes were in place, an understaffed management structure during organizational changes likely led to excessive workload for existing managers, and contributed to risks not being addressed through the operator's SMS. Safety management and oversight is an issue on the TSB Watchlist.
After the occurrence and before the 2015 spring training season started, Conair hired a safety manager and a company check pilot for the Fire Boss fleet. Conair also put forward a risk mitigation plan for 2015-16 for the company's AT-802 fleet, which addressed issues found during the investigation.
See the investigation page for more information.
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.
For more information, contact:
Transportation Safety Board of Canada
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