What happened
On Thursday, March 14, 2002, at 14:35, a Wassmer CERVA CE 43 "Guépard", registration F-BXCO, was performing a training flight at Pontoise Aerodrome. Following a flight from ToussUS-le-Noble, the student pilot completed a landing on runway 05 with flaps extended. During the landing roll, while attempting to perform post-landing procedures, the student pilot mistakenly operated the landing gear retraction lever instead of the flap retraction lever.
The instructor immediately intervened by moving the gear lever back to the down position, but the three green lights failed to illuminate. Both occupants noted a slight sinking of the aircraft. The instructor subsequently decided to execute a go-around. During the initial climb, the landing gear failed to lock in the retracted position.
While communicating with air traffic control to request emergency assistance for a subsequent landing, the instructor attempted to manually extend the gear using the emergency hand crank. However, the crank appeared to be jammed. After visually confirming the gear appeared to be down, the instructor climbed to 2,500 feet to perform a landing pattern. After shutting down the engine and positioning the propeller, the instructor performed a final approach with the flaps extended and the electrical systems turned off. Upon touchdown, the landing gear collapsed, causing the aircraft to skid to the left and come to a halt on the runway.
The investigation
The investigation focused on the mechanical state of the landing gear and the cockpit actions following the accidental retraction. Examination of the Wassmer CERVA CE 43 "Guépard" revealed that the electrical motor for the gear mechanism had failed. Additionally, the control linkages for all three landing gear legs were deformed, which prevented the gear from being operated. The switch on the right gear leg, designed to prevent retraction when the shock absorber is compressed, was found to be functional.
Findings
- The primary cause of the gear failure was the accidental retraction of the landing gear by the student pilot due to a confusion between the gear and flap controls.
- The instructor's vigilance decreased following the initial landing error, leading to an inappropriate decision to execute a go-around without ensuring the gear was properly locked.
- Post-landing actions were characterized by haste and confusion.
- The mechanical failure of the gear retraction motor and the deformation of the control linkages prevented successful manual extension of the gear.