What happened
On December 2, 2009, a Jodel D 140 E Mousquetaire, registration F-PNIV, was performing a ferry flight from the Méribel altiport to Chambéry for maintenance. The aircraft was operated by a flying club.
Prior to the flight, the aircraft had been fitted with skis on the main landing gear only. The tailwheel ski had been intentionally left off to prevent damage during the subsequent landing on the dry runway at the destination. Before takeoff, the pilot inspected the first 150 meters of the runway on foot, noting a thin layer of powdery snow between 10 and 20 centimeters. Because the apron area was clear of snow, the pilot decided to proceed with the takeoff using wheels only.
During the takeoff roll, the pilot monitored engine parameters and airspeed. Approximately 100 meters after passing the control tower, the pilot felt a sudden deceleration and the tailwheel made contact with the ground. As the aircraft approached the end of the runway, the speed had dropped to 70 km/h. The pilot attempted to use the flaps to assist the takeoff, but the deceleration continued. The aircraft exited the runway centerline, crossed the airfield perimeter road, and came to a stop on an embankment approximately 50 meters beyond the runway.
The investigation
The investigation focused on the runway conditions and the aircraft configuration. Investigators examined the snow conditions at the time of the accident and the physical state of the aircraft. It was determined that while the initial portion of the runway appeared manageable, the snow density and thickness increased in the second half of the runway compared to the apron area.
Findings
- The primary cause of the accident was the insufficient recognition of the snow quality and thickness on the runway.
- It is probable that following snowfall the previous night, the snow in the latter part of the runway was deeper and denser than what the pilot had observed during the initial foot inspection.
- This increased snow depth caused the main landing gear to sink, creating enough drag to prevent the aircraft from accelerating sufficiently for takeoff.
- The aircraft sustained heavy damage, and the pilot sustained serious injuries.