Incident Overview
On 3 January 2021, a privately registered Mooney M20F departed Airdrie Aerodrome (CEF4), Alberta, on an instrument flight rules (IFR) flight to Nelson Aerodrome (CZNL), British Columbia. The aircraft was occupied by a single pilot. En route, the pilot declared an emergency and informed air traffic control (ATC) that the aircraft's attitude indicator had failed.
Emergency Response
ATC provided several instructions to assist the pilot, who was flying in instrument meteorological conditions. During a left turn, the aircraft entered an unintentional descent and entered a valley in the vicinity of Kananaskis Lake, Alberta. The aircraft lost direct radio contact with ATC, but the pilot was able to continue relaying emergency communications through other aircraft flying in the area.
Outcome
The aircraft returned to CEF4 without further incident. The investigation was classified as a Class 4 investigation, limited in scope and without findings or recommendations.