What happened
On October 24, 1995, a CAP 232 aircraft, registration F-GPRC, was performing aerobatic training maneuvers near Calvi, France, as part of the "Festival du Vent" airshow preparations. The pilot was executing a positive roll initiated from a vertical climb. During the maneuver, the pilot applied full right rudder pedal to arrest the roll. Upon attempting to return the pedals to a neutral position, the pilot discovered that the rudder controls had jammed. Specifically, the right pedal remained stuck forward while the left pedal was stuck aft.
Despite the pilot's efforts to manually manipulate the cables and pedals, the rudder remained locked in an extreme position, causing the aircraft to yaw heavily to the right. Unable to maintain controlled flight, the pilot jettisoned the canopy and successfully parachuted from the aircraft. The CAP 232 subsequently entered a vertical dive and struck the ground at approximately 400 km/h, resulting in the total destruction of the aircraft. The pilot survived the incident uninjured.
The investigation
The investigation focused on the mechanical failure of the adjustable rudder pedal system. Investigators examined the kinematics of the rail-and-roller subsystem, which allows the pilot to adjust the pedal position. The wreckage analysis revealed that the rudder control cables were found in extreme adjustment positions.
Technical examinations of the rudder hinge and the rudder surface itself showed no signs of excessive friction or structural damage to the stops. However, the investigation scrutinized the design and certification of the adjustable pedal system. It was noted that the aircraft was operating under an experimental permit (laissez-passé) as it was undergoing type certification. The investigation also reviewed the installation procedures for the rail-roller mechanism, finding that the adjustment process was highly delicate and lacked a standardized written procedure for installation.
Findings
- The primary cause of the loss of control was a momentary jamming of the rudder control system.
- The jam was likely triggered by the high physical forces applied to the pedals during the high-G maneuver.
- The design of the adjustable rudder pedal system allowed for a failure mode where the internal components could derail from the guide rails under significant load.
- A small foreign object may have contributed to the jam, though its movement after the pilot's evacuation made it difficult to definitively isolate.
- The certification process for the system under FAR 23 regulations did not sufficiently account for the extreme stresses encountered during modern high-performance aerobatic maneuvers.
- The installation and adjustment of the pedal rails were highly sensitive to manual precision and lacked formal documented instructions.