What happened
On the morning of the occurrence, a Piper Malibu Mirage, registration C-FLER, was prepared for a private business flight from St-Mathliieu-de-Beloeil Airport, Quebec, to Burlington, Vermont. The flight was intended to be an instrument flight rules (IFR) operation with two people on board. Prior to departure, the aircraft was moved from an unheated hangar, and the pilot performed standard preparations. During this period, heavy snow had been falling for approximately two hours.
After a delay in receiving IFR clearance from the Saint-Hubert tower, the pilot initiated the takeoff roll on runway 15. As the aircraft reached 60 knots, the pilot believed the snow on the wings had been blown off by the wind. However, shortly after lifting off the ground by only a few feet, the aircraft experienced severe vibrations, engine misfires, and audible warnings. The aircraft failed to maintain flight, struck the ground with the main gear, and bounced before coming to rest in a nearby cornfield. The two occupants sustained minor injuries, and the aircraft suffered substantial damage.
The investigation
Investigators examined the aircraft's maintenance records, which showed the plane was in compliance with all airworthiness directives and had no known mechanical deficiencies. The engine was found to be capable of producing maximum power; however, the engine air filter was discovered to be saturated with water to over 75% of its thickness.
An engineering analysis was conducted to determine the required runway length for the specific weather conditions. The study suggested that a runway covered in wet snow significantly increases the required takeoff distance. Furthermore, the investigation looked into the pilot's pre-flight procedures regarding surface contamination and the impact of the wet snow on the runway surface.
Findings
- The aircraft stalled immediately after rotation because it lacked sufficient lift to sustain flight.
- The runway was contaminated with a two-hour accumulation of wet snow, which increases takeoff distance.
- The pilot did not perform a required inspection of the aircraft's critical surfaces for snow or frost immediately prior to takeoff.
- The engine air filter was saturated with water, which may have caused the engine misfires that contributed to the loss of performance.
- The aircraft's weight and center of gravity were within legal limits, and the pilot was properly qualified for the flight.