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Air transportation safety investigation A21P0001

The TSB has completed this investigation. The report was published on 13 July 2021.

Table of contents

Loss of control

Privately registered
Mooney M20F, C-GYGN
Vicinity of Upper Kananaskis Lake, Alberta

View final report

The occurrence

On , the privately registered Mooney M20F departed Airdrie Aerodrome (CEF4), Alberta, for an instrument flight rules (IFR) flight to Nelson Aerodrome (CZNL), British Columbia, with one pilot on board. En route, the pilot declared an emergency and informed air traffic control (ATC) that the aircraft's attitude indicator had failed. ATC provided several instructions in an attempt 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 to relay emergency communications through other aircraft flying in the area. The aircraft returned to CEF4 without further incident.

Media materials

News release


Investigation report: Loss of control and inadvertent descent near Upper Kananaskis Lake, Alberta, in January 2021
Read the news release

Investigation information

Map showing the location of the occurrence


Photo of Scott Ludlow

Scott Ludlow joined the TSB’s Air Investigations Branch in 2019 after having spent 15 years in private sector aviation. He has flying and training experience in commercial operations under subparts 702, 703, 704 & 705 of the CARs, and as a flight instructor. The majority of his experience was acquired in Newfoundland-and-Labrador and the Maritime provinces. He has also worked in Montreal, Qc, and Comox, BC, flying King Airs, Citations, and Dash-8. Mr. Ludlows holds a Bachelor’s degree in science (physics) and is completing his Master’s degree in Aeronautical Science (human factors and safety management).

Class of investigation

This is a class 4 investigation. These investigations are limited in scope, and while the final reports may contain limited analysis, they do not contain findings or recommendations. Class 4 investigations are generally completed within 220 days. For more information, see the Policy on Occurrence Classification.

TSB investigation process

There are 3 phases to a TSB investigation

  1. Field phase: a team of investigators examines the occurrence site and wreckage, interviews witnesses and collects pertinent information.
  2. Examination and analysis phase: the TSB reviews pertinent records, tests components of the wreckage in the lab, determines the sequence of events and identifies safety deficiencies. When safety deficiencies are suspected or confirmed, the TSB advises the appropriate authority without waiting until publication of the final report.
  3. Report phase: a confidential draft report is approved by the Board and sent to persons and corporations who are directly concerned by the report. They then have the opportunity to dispute or correct information they believe to be incorrect. The Board considers all representations before approving the final report, which is subsequently released to the public.

For more information, see our Investigation process page.

The TSB is an independent agency that investigates air, marine, pipeline, and rail transportation occurrences. Its sole aim is the advancement of transportation safety. It is not the function of the Board to assign fault or determine civil or criminal liability.