What happened
On December 1, 1963, a pilot conducting a flight demonstration at the La Chaux-de Fonds aerodrome lost control of a Fournier R.F. 3 aircraft, registration F-BLET. The pilot had been authorized to perform a series of "lazy eight" maneuvers to present the aircraft to local officials.
During the second pass of the maneuver, while flying at a low altitude, the aircraft experienced a sudden loss of control. The pilot initially believed the aircraft was encountering turbulence from the previous pass, but later clarified that an aggressive input on the elevator caused the aircraft to enter a high-speed stall. The aircraft struck the ground tangentially, causing the propeller to break and the wings and fuselage to sustain significant damage. Following the impact, the aircraft bounced and slid across the terrain, coming to a halt approximately 400 meters from the initial contact point. The pilot escaped the incident without injury.
The investigation
An investigation was initiated immediately following the accident. Investigators inspected the aircraft and examined the ground tracks at the aerodrome. The investigation focused on the pilot's maneuvers, the aircraft's mechanical condition, and the environmental factors present at the time of the accident. Meteorological observations confirmed clear skies, unlimited visibility, and calm winds.
Findings
- The primary cause of the accident was a high-speed stall induced by the pilot's excessive elevator input during a low-altitude maneuver.
- The pilot's attempt to recover from perceived turbulence led to an abrupt pull on the control column, resulting in the loss of control.
- The aircraft's mechanical systems, including the flight controls, were found to be in normal working order.