Accident Details
On October 26, 2019, at approximately 0745 Central Daylight Time, a float-equipped de Havilland DHC-3 Otter (registration C‑GBTU, serial number 209) operated by Blue Water Aviation departed Bissett Water Aerodrome, Manitoba. On board were the pilot, two passengers, and approximately 800 pounds of freight. The intended destination was Little Grand Rapids, Manitoba, located on the eastern shore of Family Lake.
At approximately 0845, while on approach to Family Lake, the aircraft’s right wing separated from the fuselage. The aircraft subsequently entered a nose‑down attitude and struck the water surface. The pilot and the two passengers sustained fatal injuries. The aircraft was destroyed by impact forces. The emergency locator transmitter activated momentarily.
Investigation Findings
The official investigation determined that a fatigue fracture originated in the bolt hole bore of the right‑hand wing lift strut’s upper outboard lug plate. This fatigue crack eventually caused an overstress fracture of both the right‑hand wing lift strut’s upper outboard and inboard lug plates during the left turn prior to the final approach. The failure of these lug plates led to the separation of the right‑hand wing lift strut from the wing, and subsequently, the separation of the right wing from the aircraft.
Additional Observations
The investigation also noted that when operational flight plan data and load calculations are not available, there is a risk that important aircraft information—including the number of occupants, route, cargo, and weight‑and‑balance details—will not be accessible for search‑and‑rescue operations or accident investigation. Furthermore, the detailed visual inspection prescribed in the Viking Air Ltd. Supplementary Inspection and Corrosion Control Manual, and required by Airworthiness Directive CF2018‑4, did not identify cracks that could form in the right‑hand wing strut’s upper outboard lug plate.