What happened
On a daylight charter flight from Iqaluit, a DHC-6 Twin Otter, registration not provided, was transporting six barrels of Jet B fuel to an off-strip landing site at Markham Bay. During the landing sequence, the aircraft experienced multiple bounces on the gravel surface. Following the touchdown, the crew attempted an overshoot. The aircraft traveled past the end of the landing area, where it encountered a 11-degree downslope. After the brakes were released, the aircraft became airborne 34 metres beyond the runway end. However, the aircraft failed to clear a ridge located 185 metres past the lift-off point. The aircraft struck a rock, causing the right main gear to detach, and subsequently stalled while crossing the ridge. The plane crashed into a rocky beach and became partially submerged in water. The two fatalities involved were the captain and the first officer.
The investigation
The investigation examined the aircraft's weight, the landing site, and the mechanical condition of the engines and controls. It was established that the aircraft was operating significantly above its maximum authorized take-off and landing weights. The investigation also looked into the engine mounts, finding that several mounts exhibited fatigue cracking, including the broken inboard isolation mount on the right engine.
Analysis of the landing marks indicated that the aircraft had high residual airspeed and was likely using a 20-degree flap setting—a setting typically used for short-field take-off rather than landing. The engines were found to be producing high power at the time of impact, suggesting the crew had advanced the throttles to attempt the overshoot. While the first officer sustained injuries suggesting he may have been at the controls, the presence of steering input on the captain's control wheel meant it could not be determined with certainty who was flying the aircraft.
Findings
- The aircraft was loaded to weights exceeding both the maximum authorized take-off and landing limits.
- The crew attempted to overshoot the landing area despite insufficient runway remaining for the necessary acceleration and climb.
- The aircraft stalled while attempting to clear an obstacle due to low airspeed and insufficient altitude.
- The landing was characterized by multiple bounces and difficulty in maintaining control.
- The aircraft was using a flap setting of 20 degrees, which is inconsistent with standard landing procedures for short strips.