Twin Otter Landing Gear Failure After Dock Takeoff in Goose Bay

Incident Overview and Damage Assessment On 1631 Atlantic standard time, a de Havilland DHC-6-300 Twin Otter, registration C-FIZD, was repositioning from the Marine Atlantic dock to Goose Bay Airport after a float-to-wheel landing gear conversion. During the takeoff from the dock, the aircraft's main wheels struck a wooden safety curb surrounding the dock perimeter. The pilots conducted an in-flight visual inspection of the landing gear, concluded there was no visible damage, and continued the flight. Upon landing at Goose Bay Airport, the right main gear collapsed and separated from the aircraft. The aircraft veered to the right and came to rest on a taxiway on the right side of the runway. Damage was sustained to the right landing gear, the right wing tip, and the outboard aileron hinge. The two pilots on board were not injured. ## Operational Context and Environmental Factors The accident occurred approximately one hour before sunset. Weather conditions at Goose Bay Airport included a surface wind of 250° magnetic at 7 knots, visibility of 15 statute miles, scattered clouds, and a temperature of 0°C. Strong winds were forecast for the following days. The aircraft had been taxied from the floatplane base to the marine dock early in the day with minimum fuel. Maintenance personnel removed the floats and installed wheel landing gear, and unnecessary equipment was removed to reduce takeoff weight and distance. The captain and first officer arrived at the Port of Goose Bay main dock at approximately 0830 Atlantic standard time. This was the first takeoff from the dock for both the operator and the captain. ## Takeoff Procedure and Contributing Factors The aircraft was operated under Canadian Aviation Regulations Part VII, Subpart 4, Commuter Operations (CAR 704). The company operations manual required maximum performance STOL (MPS) takeoff procedures, including annual ground and flight training, a minimum of three MPS takeoffs annually, and certification by the chief pilot. All requirements were met except for consultation with the Director of Flight Operations or chief pilot prior to first-time operations from the site. The captain estimated the available takeoff distance at approximately 400 feet by pacing, while the actual measured distance was 335 feet. The captain calculated a required takeoff ground run of approximately 300 feet using performance charts. A depression in the dock surface, approximately 60 feet wide and 1.5 feet deep, was located about 105 feet from the water side. During the takeoff, the nose landing gear settled into this depression at approximately three-quarters of the available distance, causing a momentary decrease in wing angle of attack and delaying rotation. The right main landing gear struck the wooden safety curb, and the left main gear struck and severed a partially decomposed 10-foot section of the curb. ## Post-Accident Findings and Equipment Issues The cockpit voice recorder was not recording during the accident flight because the integral inertial switch had activated at an unknown time before the flight. The switch could be activated with less than the certified required g-force. Examination of the aircraft revealed no mechanical, maintenance, or performance discrepancy that contributed to the accident. The emergency locator transmitter (ELT), a Pointer Sentry model 4000-10, was found detached from its mounting bracket, likely due to impact forces. The installed bracket was approved under Technical Standard Order C91 but was intended for an earlier model ELT. The correct bracket for the model 4000-10 ELT is part number 2017-10, which uses a hold-down strap instead of a rear bracket clip. The New Zealand Civil Aviation Authority issued an airworthiness directive requiring TSO C91A brackets for certain Pointer ELT models, while Transport Canada had not issued similar directives.