Investigation Summary
The accident was initiated by a fatigue failure in the low pressure impeller of the Rolls-Royce Dart engine. The uncontained failure was so violent that the forward portion of the number 2 engine separated from the wing. This separation caused two critical secondary problems: first, debris severed or damaged the electrical circuits required to retract the landing gear, leaving the wheels down and creating significant parasitic drag. Second, the loss of engine mass, combined with the movement of passengers toward the rear of the cabin during the emergency, shifted the center of gravity beyond its aft limit. The crew attempted a right-hand turn to return to the airport, but the high-drag configuration and asymmetric thrust caused the airspeed to decay below the minimum control speed (Vmc). The aircraft rolled and struck the ground in a farm field, breaking apart and catching fire. Rescue efforts were significantly hampered by the spring thaw, as heavy fire trucks became stuck in deep mud, necessitating the use of tracked snowcats to transport victims and equipment.
Final Conclusions
The investigation identified the uncontained failure of the low pressure impeller in the number 2 engine, caused by undetected fatigue cracks, as the initiating event. The resulting engine separation and inability to retract the landing gear created a drag profile that exceeded the aircraft's single-engine climb performance. While the final report did not include a formal 'Probable Cause' statement, it detailed that the combination of high drag, aft center of gravity shift, and loss of airspeed led to a loss of control at or below Vmc.
Video Analysis
Catastrophic Failure on Takeoff At Quebec Airport - The Fall of Quebecair 255 — A detailed recreation and analysis of the March 29, 1979 accident involving a Fairchild F-27 that suffered an engine separation during takeoff from Quebec City.
If playback is blocked, the owner has disabled embedding — use the link above.
Airframe & Maintenance
Crew Experience
Captain
André Bessette, a former Canadian Air Force pilot.
First Officer
Alain Willaume.
Systems & Failure Modes
Rolls-Royce Dart Engine
The turboprop engine suffered an uncontained failure of the low pressure impeller, leading to the separation of the forward engine assembly.
Landing Gear Selection Circuitry
The electronic circuits responsible for gear retraction were located near the engine and were severed by debris, leaving the gear locked down and increasing drag.
Cockpit Voice Recorder (CVR)
The CVR was recovered and provided useful information to investigators, unlike the Flight Data Recorder which provided limited data.
Interesting Facts
- 01The aircraft was 21 years old at the time of the accident.
- 02The low pressure impeller burst due to fatigue cracks that had not been detected during maintenance.
- 03The landing gear remained extended throughout the flight because debris damaged the electronic gear selection circuitry.
- 04Rescuers had to use tracked vehicles (snowcats) because fire trucks became stuck in the mud caused by the spring snowmelt.
- 05The center of gravity shifted beyond the aft limit due to the physical loss of the engine and passenger movement.
- 06A survivor reported that one passenger may have died of a heart attack just prior to the crash, contributing to the movement of passengers in the cabin.
Safety Actions & Advisories
Impeller Inspection Protocols
The investigation highlighted the need for more rigorous detection methods for fatigue cracks in engine impellers to prevent uncontained failures.
Landing Gear Selector Valve Relocation
Source ↗The investigation recommended that the landing gear selector valve and its associated control lines be relocated or better protected to prevent a single engine failure from disabling the gear retraction system.