What happened
On September 2, 2007, a private Beechcraft B 35 Bonanza, registered HB-ECD, was performing a flight from Annecy Airport to Grenchen, Switzerland. During the takeoff roll on runway 22, the pilot retracted the landing gear. Shortly after liftoff, the right-side cabin door partially opened.
Faced with the door failure and considering the remaining runway length, the pilot elected to perform an immediate landing. However, the landing gear remained in the retracted position. The aircraft contacted the runway with the gear up, skidding for approximately 100 meters before veering right off the paved surface. The aircraft crossed the runway shoulder and came to a stop roughly 15 meters from the edge of the runway, oriented 90 degrees to the runway centerline. The aircraft sustained heavy damage.
The investigation
The investigation focused on the sequence of events leading to the gear-up landing and the recurring issue with the aircraft's door. Investigators examined the aircraft's flight manual, which specifies that after closing the door, the pilot must press firmly on the upper rear corner and, if any movement is detected, fully reopen and reseal the door. While the pilot stated he had verified the door lock before alignment, the door opened approximately 30 degrees during the takeoff roll, eventually settling at an opening of 10 to 15 degrees.
Evidence emerged regarding the history of this specific airframe. The aircraft owner noted that the door had uncommandedly opened at least three times over the previous 25 years, despite proper closure checks. In previous instances, the pilot had continued the flight at low speeds to reseal the door in flight. Additionally, it was noted that the aircraft lacked any visual or audible warnings to alert the pilot if the landing gear had not been extended.
Findings
- The primary cause of the accident was the inappropriate decision to interrupt the takeoff once the door failure occurred.
- The pilot attempted an emergency landing with the landing gear still retracted.
- The aircraft's door had a documented history of intermittent failure to remain closed during flight.
- The aircraft was not equipped with a landing gear warning system to alert the crew of the retracted state during the landing attempt.