What happened
During preparations for a non-scheduled Part 135 cargo flight, a pilot conducted preflight inspections on a wheel-equipped airplane that had been stored overnight with engine covers and an electric heater. Due to extreme ambient temperatures of approximately -20 degrees Fahrenheit, the pilot noted that the engine oil pressure appeared low upon startup, though it remained within the functional operating range. After consulting with the company owner regarding the low pressure, the pilot proceeded with the flight.
While flying over ocean waters toward a remote village, the pilot reported that the oil pressure had stabilized. However, roughly ten minutes later, an emergency was declared. The aircraft ditched in the water approximately 18 miles west of the departure airport. GPS data indicated the aircraft reached a maximum altitude of 1,439 feet msl during its transit across the ocean. The wreckage was located two hours later, floating nose-down near pan ice, roughly 8.8 miles from the initial ditching site. The pilot was not found during the recovery efforts.
Findings
Post-accident inspection of the engine revealed a significant 8 x 5 inch hole in the top of the engine case near the number 2 cylinder. Investigators determined that the number 2 connecting rod had broken from both the piston and the crankshaft journal. Furthermore, the number 1 connecting rod bearing was displaced and showed signs of extreme heat. The investigation identified evidence of oil starvation and high heat signatures across several crankshaft and connecting rod bearings, accompanied by fragmented bearing material.
Several contributing factors were noted during the investigation:
- The pilot was not utilizing personal flotation equipment.
- The survival window in the 29 degree Fahrenheit water was estimated at only 30 minutes.
- The company's operations manual lacked a specific policy requiring pilots to maintain enough altitude to reach land when flying over water.