What happened
On 9 August 2019, a Beechcraft Bonanza A36, registration OO-JBM, was conducting a private cross-country flight along the Corsican coast. After departing Calvi-Sainte-Catherine, the aircraft was cruising at approximately 2,000 ft when two loud bangs were heard, followed by a decrease in manifold pressure and airspeed. Shortly thereafter, the engine shut down.
The pilot attempted several restart procedures, including checking fuel selection, mixture, and the electric pump, but the engine failed to restart. Realizing the aircraft could not reach land, the pilot decided to ditch the aircraft in the sea near the Île de Cargalo, aiming to land close to nearby pleasure boats for assistance. The pilot opted to perform the ditching with the landing gear and flaps retracted.
As the aircraft approached the water, it stalled approximately ten meters above the surface. The right wing and the nose of the aircraft struck the sea, causing the aircraft to settle in a nose-down attitude. The weight of the engine caused the forward section of the fuselage to submerge rapidly. The pilot and passenger, who were not wearing life jackets, managed to evacuate the cockpit after the passenger unlocked the door prior to impact. Both occupants sustained injuries, including a broken jaw for the pilot, and were rescued by nearby sailors.
The investigation
The BEA investigation focused on the sequence of events leading to the engine failure and the subsequent stall. Investigators examined the aircraft's maintenance history, noting recurrent oil leaks and a missed 50-hour inspection. The investigation also reviewed the pilot's flight management, the configuration of the aircraft during ditching, and the survival equipment on board.
Findings
- The engine shutdown was the primary catalyst for the emergency.
- The aircraft stalled during the flare because the pilot's attention was focused on navigating around boats, and the aircraft was flown in a clean configuration (flaps retracted), which resulted in a higher stall speed.
- The pilot was not aware of the specific stall speed for the clean configuration.
- The stall warning was not detected, potentially due to the high-stress environment or the fact that the stall warning system becomes inoperative if the battery/alternator switches are set to OFF.
- The occupants did not wear life jackets during this leg of the flight, as they were flying close to the coast and had not yet donned them.
- The passenger's decision to unlock the door before impact was critical, as the structural deformation of the aircraft during the impact likely would have prevented evacuation otherwise.