A Transportation Safety Board accident investigation report into the crash last summer of a Fort Langley Air Cessna 180H into British Columbia’s Tyaughton Lake was released this week. The TSB determined that the aircraft experienced an accelerated stall while attempting to return to the point of takeoff. In the accident, both the front-seat and rear-seat passengers were fatally injured and the pilot sustained serious injuries.

The aircraft took off from Tyax Lodge on the northwestern side of the lake, that generally runs north-south. While climbing southward after take-off, at about 300 feet above the lake surface, the rear-seat passenger, also a pilot, noted that fuel was leaking from the left wing tank. He advised the pilot to turn around. The aircraft then entered a steep turn, necessitated by the surrounding terrain.

This TSB-annotated illustration shows the flight path of the Cessna 180H.

Density altitude at the time was calculated by the TSB to be 5,250 feet asl, which would have resulted in an increase in turning radius of about 15 percent compared to a similar turn at sea level in standard day conditions.

The TSB determined that the aircraft and pilot conformed with all regulations and standards. They also noted that no-one on board the aircraft was wearing a personal flotation device, that there was no emergency exit from the rear of the aircraft and that the pilot had not received emergency egress training.

In the report, the TSB repeated recommendations that resulted from investigations into similar accidents in the past:

  • “[That] the Department of Transport require that all new and existing commercial seaplanes be fitted with regular and emergency exits that allow rapid egress following a survivable collision with water.” (TSB Recommendation A11-05);
  • “[That] the Department of Transport require that occupants of commercial seaplanes wear a device that provides personal flotation following emergency egress.” (TSB Recommendation A11-06);
  • “(That] the Department of Transport require underwater egress training for all flight crews engaged in commercial seaplane operations.” (TSB Recommendation A13-02).
The Cessna 180H lies upside down and almost completely submerged in B.C.’s Tyaughton Lake.

The complete TSB Investigation Report (A18P0108) can be found here.