What happened
On April 11, 2001, a Beechcraft M 35 Bonanza, registered F-BOID, was conducting a private flight from Grenoble St Geoirs to Grenoble Le Versoud. During the initial startup at the departure airfield, the pilot was unable to start the engine using standard methods and instead utilized a ground power unit. During this process, the pilot noted that the alternator galvanometer needle remained just above zero, though they proceeded with the flight.
Upon arrival at the destination, the pilot experienced a total loss of radio communication. Shortly thereafter, the pilot discovered that the landing gear would not extend, as the gear position indicator failed to illuminate. In an attempt to rectify the situation, the pilot attempted to use the manual emergency extension crank. After completing thirteen turns, the pilot found the crank had become blocked. Due to uncertainty regarding the aircraft's configuration and the inability to confirm the gear status, the pilot proceeded to land on the runway with the landing gear retracted, resulting in slight damage to the aircraft.
The investigation
The investigation focused on the mechanical behavior of the landing gear and the pilot's use of emergency equipment. Investigators established that during the initial attempt to extend the gear via normal operating mode, the gear only partially deployed. Furthermore, the investigation revealed that during the attempt to use the emergency extension crank, the pilot inadvertently turned the handle in the direction used for gear retraction.
Findings
- The pilot possessed insufficient knowledge of the aircraft's specific characteristics, specifically regarding the manual extension process, which requires approximately fifty turns of the crank to fully deploy the gear.
- The pilot performed an inadequate execution of emergency procedures by turning the crank in the wrong direction.
- The pilot failed to monitor the landing gear indicator light during the emergency procedure.
- There was an indication of an electrical issue at departure, as a functional alternator charging a battery should produce a significant deflection on the galvanometer needle.