What happened
On August 18, 2004, a Piper J3 C-65 (registration HB-ONH) was involved in an accident during an attempt to depart from a harvested wheat field at the Gardette estate near Buis-les-Baronnies. The flight was part of a journey intended to return the aircraft to Switzerland.
The previous evening, the pilot and a passenger had performed an emergency landing in the field to avoid developing thunderstorms while flying from Montélimar to Aubenasson. On the morning of the accident, the pilot decided to depart from the field to meet a deadline for returning the aircraft to Switzerland. Relying on television weather forecasts, the pilot planned the takeoff in the direction opposite to the previous landing.
During the takeoff roll, the aircraft failed to reach rotation speed. As the aircraft approached the edge of the usable field, the pilot pulled back on the control column. The aircraft subsequently struck sorghum crops in an adjacent field, causing the plane to flip onto its back. The aircraft was heavily damaged in the event, and there were no fatalities among the two occupants.
The investigation
The investigation established that the usable length of the wheat field was approximately 160 meters, while the adjacent sorghum field measured roughly 230 meters. The pilot had not verified the ground conditions or measured the available runway length prior to the attempt. Furthermore, the ground was saturated due to heavy rainfall the previous day.
According to the aircraft's flight manual, for a takeoff mass of 530 kg, a takeoff distance of approximately 500 meters (to clear a 15-meter obstacle) and a ground roll of 280 meters are required on a horizontal, dry grass runway. The pilot also noted that they were unaware of the requirement to notify authorities regarding the previous off-airport landing.
Findings
- The primary cause of the accident was the aircraft flipping onto its back due to an insufficient takeoff distance and an attempt to rotate prematurely.
- The pilot demonstrated a persistence in attempting the flight despite unfavorable conditions.
- There was an insufficient assessment of the environmental factors, specifically the saturated state of the soil and the lack of adequate runway length for the aircraft's weight and atmospheric conditions.