Fatal training accident involving Cessna 152 near Saskatoon

Q: What aircraft was involved and where did it happen?

The accident on 1997-10-04 involved a Cessna 152 C-GZCT, operated by Mitchinson Flying Service Limited, at Vanscoy, Saskatchewan 4 nm S, CA.

On October 4, 1997, a Cessna 152 C-GZCT operated by Mitchinson Flying Service Limited was involved in an aviation accident near Vanscoy, Saskatchewan 4 nm S, CA. Investigators recorded the probable cause as: The aircraft entered a secondary stall at an altitude too low for recovery while the crew was attempting to recover from a training maneuver that had been continued below the safe minimum altitude. This summary draws on records from the Transportation Safety Board of Canada (TSB).

Sourcesthe Transportation Safety Board of Canada (TSB)Primary reportUpdated 1785068748Data API Editorial standards

A training flight in a Cessna 152 ended in a fatal crash near Vanscoy, Saskatchewan, after a spin maneuver was continued below a safe altitude.

What happened

A Cessna 152 departed Saskatoon, Saskatchewan, for a flight intended to practice stalls, spins, and slow flight. The crew operated within the CYA 306(T) training area, performing various maneuvers between 4,000 and 4,500 feet above sea level. During the session, the aircraft entered a spin at approximately 4,000 feet. Radar data and witness accounts indicate the aircraft continued its descent, eventually reaching an altitude of about 200 feet above ground level near Vanscoy. A witness observed the aircraft momentarily in a level attitude before it banked sharply to the left and struck a field. Both occupants, a highly experienced pilot and a student instructor, were fatally injured.

The investigation

The investigation focused on the aircraft's mechanical condition and the physiological state of the crew. While the aircraft's control systems and engine were found to be functional, investigators identified a small hole in the number 4 cylinder exhaust stack. This leak allowed exhaust gases to accumulate in the engine cowling and potentially migrate into the cockpit.

Toxicology results showed carbon monoxide levels in both pilots, with the pilot-in-command measuring between three and nine per cent and the student between zero and five per cent. When accounting for the reduced oxygen availability at 4,000 feet, the effective physiological impact was higher. Additionally, the post-mortem examination of the pilot-in-command revealed mild atherosclerosis, which could potentially increase susceptibility to angina when combined with carbon monoxide exposure.

Findings

The aircraft entered a secondary stall during an attempt to recover from the initial spin, but the low altitude prevented successful recovery.
An exhaust leak in the number 4 cylinder stack allowed carbon monoxide to enter the cabin.
The crew was exposed to low levels of carbon monoxide, which may have contributed to physiological effects.
The training maneuver was continued below the regulatory minimum altitude for aerobatic maneuvers for reasons that remain undetermined.
The instructions for the installed carbon monoxide detector were obscured by its mounting, making it difficult for the crew to monitor for leaks during flight.

Probable cause

The aircraft entered a secondary stall at an altitude too low for recovery while the crew was attempting to recover from a training maneuver that had been continued below the safe minimum altitude. Potential contributing factors included physiological effects from low-level carbon monoxide exposure and the possibility of undetected medical incapacitation.

Loss of control in flight

1997-10-04: Cessna 152 C-GZCT — Mitchinson Flying Service Limited — Vanscoy, Saskatchewan 4 nm S, CA