What happened
On a night flight from Hornepayne to Timmins, Ontario, an Air Bravo Pilatus PC-12/45, registration C-FPCN, experienced a sudden loss of engine oil while cruising at 15,000 feet. The flight crew, consisting of two pilots and a paramedic, observed a drop in engine torque followed by several warnings, including low oil pressure and a chip detector light. The loss of oil was severe enough that oil began to cover the cockpit windscreen, significantly obscuring visibility.
In response to the emergency, the crew maintained their altitude to preserve gliding distance before beginning a descent. During the approach to Runway 10 at Timmins, the crew faced challenging conditions, including night, instrument meteorological conditions, and a windscreen obscured by oil. The aircraft touched down at approximately 130 knots, which was significantly higher than the standard landing speed. The high speed and long touchdown caused the aircraft to overshoot the runway, traveling 1,200 feet past the end of the pavement before coming to a stop in the snow. The crew sustained no injuries, though the aircraft suffered substantial damage.
The investigation
Investigators examined the engine and found that a B nut on a 90-degree fitting at the oil outlet of the torque limiter had become completely disconnected. This failure allowed the engine's usable oil to be pumped overboard. The investigation also noted that two sets of clamps were missing from the associated plumbing. Post-accident inspection of the engine revealed that the magnetic chip detector and oil filter were heavily contaminated with both ferrous and non-ferrous debris.
Regarding the landing, the investigation found that the crew's focus was likely narrowed by the urgency of the engine failure and the difficulty of seeing the runway through the oil-covered windscreen. While the crew chose Runway 10, the investigation noted that Runway 21 was longer and offered more favorable wind conditions. The aircraft's touchdown speed was estimated at 130 knots, roughly 60 knots above the normal landing speed for the configured flaps.
Findings
- For undetermined reasons, a B nut fitting on the torque limiter's oil outlet loosened, resulting in a complete loss of engine oil.
- The flight crew did not effectively manage the final approach and landing speed, leading to a high-speed touchdown and runway overrun.