What happened
On October 2, 1969, a Beech 95-A55 Baron, registration D-IAEC, departed from the Neuchâtel aerodrome for a dual-control training flight. The flight began with an unusually long takeoff roll, utilizing nearly the entire length of the runway. After lifting off, the aircraft initially climbed at a shallow angle before performing a sharp left-hand roll (renversement).
Following this maneuver, the aircraft crossed the centerline of the runway and entered a steep climb. At an altitude of approximately 150 meters, the aircraft entered a spin. The aircraft subsequently impacted the ground at the southeastern edge of the grass runway at a 70-degree longitudinal pitch and immediately caught fire. Both pilots were killed in the accident, and the aircraft was destroyed. There was no significant damage to property on the ground.
The investigation
Investigators examined the wreckage and the flight circumstances to identify any mechanical failures or pilot errors. The aircraft was found to be airworthy, and the engines were running at high power throughout the observed maneuvers. While the wreckage was heavily damaged by the impact and fire, making the inspection of instruments difficult, investigators found that the control cables and trim systems were intact.
One area of interest was the control column locking pin, which could be used to immobilize the elevators and ailerons. Although the pin was not recovered from the wreckage, the position of the control column cylinders suggested the pin was not inserted at the time of impact. Subsequent flight tests using a similar Beech 9/A55 Baron demonstrated that while a takeoff is possible with a blocked control column using heavy nose-down trim, the aircraft tends to enter a steep climb, which does not perfectly align with the observed flight path.
Findings
- The aircraft was performing maneuvers that were strictly prohibited by the Airplane Flight Manual (AFM), which forbade aerobatics including spins.
- The pilots had performed an unusually brief pre-flight check, which may have led to an oversight regarding the control column lock.
- There was no evidence of pilot impairment, such as alcohol or medical emergency, and the weather conditions were excellent.
- It remains possible that the unusual maneuvers were intentional, as the pilot on the right seat had recently discussed aerobatic displays and possessed aerobatic experience.
- The investigation could not rule out the possibility that the flight path was dictated by an unforeseen mechanical obstruction, such as a loose component or foreign object, rather than intentional maneuvering.