Engine failure leads to forced landing of Mooney M-20C in Yukon

Casualties unknown • CA

A Mooney M-20C aircraft experienced a total loss of engine power during a flight in the Yukon, resulting in a forced landing and minor injuries.

What happened

A Mooney M-20C, registered CF-MBV, disappeared while performing a visual flight rules (VFR) trip from Dawson to Watson Lake, Yukon Territory. The aircraft's flight path originally intended to include a stop in Faro, but the pilot eventually deviated from the planned route and altitude. Following a search by the Rescue Coordination Centre, the aircraft was located the following day approximately 50 nautical miles southwest of Ross River. The aircraft sustained substantial damage during a forced landing, though the pilot and passenger survived with minor injuries.

The investigation

The investigation focused on the loss of engine power during cruise flight. Investigators found that the aircraft had been flown into instrument meteorological conditions (IMC) at an altitude of 11,500 feet, well above the freezing level. The flight took place in an environment characterized by high relative humidity.

Technical examination of the engine revealed it was in a time-worn state, with evidence of broken and stuck piston rings in the No. 3 cylinder. While these issues could contribute to power loss, they did not explain the total loss of power. The investigation also noted that the pilot's use of carburettor heat may have inadvertently caused accumulated ice to melt and enter the cylinders, further impacting engine performance. Additionally, the search efforts were complicated by the lack of an emergency locator transmitter (ELT) signal and poor weather.

Findings

  • The primary cause of the engine power loss was likely carburettor icing.
  • The pilot elected to continue a VFR flight into IMC without the necessary instrument certification.
  • The aircraft was operated at high altitude without the required oxygen or equipment.
  • The flight was conducted in icing conditions for which the aircraft was not certified.
  • The pilot deviated from the filed flight plan without notifying Air Traffic Services.
  • The aircraft lacked the necessary emergency survival equipment for the sparsely populated region.
  • The pilot did not declare an emergency following the engine failure.

Probable cause

The engine power loss was likely caused by carburettor icing, exacerbated by the pilot's decision to fly into instrument meteorological conditions while only certified for visual flight rules.

Frequently asked questions

What happened in the 1994-08-22 Ross River, Yukon Territory 50 nm SW accident near CA?

A Mooney M-20C aircraft experienced a total loss of engine power during a flight in the Yukon, resulting in a forced landing and minor injuries.

What aircraft was involved and where did it happen?

The accident on 1994-08-22 involved a Ross River, Yukon Territory 50 nm SW, operated by Mooney M-20C CF-MBV, at CA.

What was the probable cause of the accident?

The engine power loss was likely caused by carburettor icing, exacerbated by the pilot's decision to fly into instrument meteorological conditions while only certified for visual flight rules.

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