Float plane crashed, killing three, because pilot unfamiliar with modified airplane: TSB
Wreckage and tree strike damage. The pilot of a commercial Air Cab float plane that crashed on West Cracroft Island was new to the company and unaware of how multiple modifications affected the airplane's performance and handling, the federal transportation safety board has determined.
Photograph by: Vancouver Sun , Transportation Safety Board
The pilot of a commercial Air Cab float plane that crashed on West Cracroft Island was new to the company and unaware of how multiple modifications affected the airplane's performance and handling, the federal transportation safety board has determined.
Pilot Kevin Williams and passengers Norm Slavik of Surrey and Fred Wiley of Merville died after the 1970 Cessna C-185E stalled shortly before landing and crashed onto a small island on Potts Lagoon east of Port McNeill at 11:40 a.m. on Oct. 24, 2013.
In a report released Wednesday, the board said the pilot had accumulated about 3,137 hours total flight time, 1,682 hours of those in seaplane operations.
The pilot had started working for the company 10 days before the accident. The accident occurred on the pilot's first day of unsupervised flying for Air Cab. The pilot had not flown to the Potts Lagoon area and had not flown the accident aircraft before the day of the crash.
The airplane had received multiple approved modifications over the years, and the pilot would not have known how all these would have changed the performance of the airplane.
"The aircraft's high bank angle, steep descent, short wreckage trail, and low airspeed were consistent with the occurrence of an accelerated aerodynamic stall at an altitude from which recovery was not possible," the board found.
The aircraft had been involved in three prior accidents, most recently in September 2012, when it was significantly damaged after it stalled in a low-level left turn and crashed into water.
At the time of repair, the aircraft received a wing-extension modification, which followed earlier installations of two takeoff-and-landing kits. The plane had also been fitted with larger floats.
Because the modifications resulted in performance and handling characteristics unique to the aircraft, the actual stall speed of the aircraft "remained unknown and could only be estimated" and may have compromised the ability of the stall warning system to indicate an impending stall.
An advanced stall warning system may have made a difference.
The board concluded that the "installation of multiple modifications without adequate guidance on how to evaluate and document the effects on aircraft handling" may result in pilots losing control due to unknown aircraft performance.
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