History of the Flight
On the morning of the occurrence, the pilot departed Makovik, Labrador, with five passengers. About 12 minutes into the flight, the engine chip light illuminated. The pilot landed the Bell 206L helicopter, shut down the engine, and removed the chip detector. Finding only a small quantity of metal paste (fuzz) on the forward-facing detector, the pilot cleaned and reinstalled it, then took off to continue the flight.
Two minutes after takeoff at an altitude of 1,000 feet above ground level, three loud bangs were heard, followed immediately by a complete loss of engine power. The pilot entered autorotation and carried out a forced landing on a coastal flat. During the landing, the front of the skid landing gear dug into the soft surface, causing the main rotor to rock fore and aft and strike the tailboom, severing it completely. After the rotor came to a stop, the pilot activated the emergency locator transmitter, and all six occupants evacuated the helicopter without injury.
The accident occurred at approximately 1200 Atlantic daylight saving time at sea level, in visual meteorological conditions (overcast ceiling 1,200–1,500 feet, visibility 15 miles, temperature 4°C, wind northwest at 20 knots).
Injuries to Persons
There were no injuries. The pilot and five passengers were uninjured.
Damage to Aircraft
The helicopter sustained substantial damage from the main rotor striking and severing the tailboom. Additionally, the helicopter was partially submerged in salt water when the tide came in before recovery.
Personnel Information
The pilot, aged 23, held a Commercial Pilot Licence – Helicopter and had 2,620 total flying hours, with 2,490 hours on type. He was properly licensed and qualified for the flight.
Aircraft Information
The helicopter was a Bell 206L Long Ranger (serial number 45040) with a total airframe time of 6,188.7 hours. It was powered by a single Allison 250-C20R engine (serial number CAE295364) with 1,718.9 hours since new. The helicopter was maintained, certified, and equipped per regulations; weight and centre of gravity were within limits.
Engine Examination
Post-accident examination revealed a mechanical lockup of the N1 shafting system. The engine was disassembled; the No. 1 compressor bearing had failed. Detailed laboratory examination concluded that the bearing failed due to separator and/or roller wear. No cracks were detected, and no metallurgical cause for failure could be established. Materials met chemical composition and hardness requirements. Oil flow through the pressure reducer was satisfactory.
A review of engine records showed a previous chip light at 1,606.2 engine hours, with a log entry noting a few small chips on the forward-facing chip plug. No metal was found during a subsequent 200-hour inspection.
Maintenance and Training
The Allison 250-C20R Operations and Maintenance Manual specifies that if a chip light illuminates, the pilot should land and inspect magnetic plugs. Particles such as chips, flakes, slivers, and fuzz are potential indicators of bearing or gear failure. Chips or flakes exceeding 1/32 inch or more than four slivers require engine removal; smaller particles are acceptable but require a 30-minute ground run after plug reinstallation. If the light illuminates during the ground run or within eight subsequent flight hours, the engine must be removed.
The pilot had not been briefed on the significance of recurring chip lights or the requirement for a 30-minute ground run. The flight operations manual contained no guidance on checking chip detectors, and pilot training on such tasks was informal, relying on discussions with maintenance personnel rather than formal instruction.
Probable Cause
The Board determined that the pilot incorrectly assessed the engine as airworthy and took off to continue the flight. The engine stopped two minutes after takeoff when the No. 1 bearing failed as a result of separator and/or roller wear. The reason for the bearing failure could not be determined. Contributing to the occurrence was the lack of adequate training for pilots on checking chip detectors and the absence of guidance in the flight operations manual.