What happened
On July 18, 1965, a U3M Pelikan, registration HB-TBW, departed from the Speck-Fehraltorf airfield for a private flight. The aircraft, which was undergoing pattern testing, was carrying the pilot and three passengers. Shortly after takeoff, the aircraft began a left-hand turn at an altitude of approximately five meters. The pilot attempted to correct the deviation, but found the control stick was jammed and could not be moved to the right.
As the aircraft entered a steep descending left turn, it reached a maximum altitude of 1,520 meters before striking the ground in a field south of the airfield. The impact caused the aircraft to capsize. All four occupants sustained serious injuries, and the aircraft was destroyed.
The investigation
The investigation focused on the mechanical failure of the flight controls and the cabin environment. Investigators examined the cockpit configuration, noting that the aircraft featured two control sticks arranged in a U-shape. The investigation also reviewed the aircraft's maintenance and testing history, noting that the aircraft was operating under a restricted permit for technical testing purposes.
Physical evidence was recovered from the wreckage, specifically a Kodak Retina Reflex III camera in a carrying case. The dimensions of the camera case matched pressure marks found on the case that aligned with the angled portion of the right control stick. Investigators also noted that the aircraft's takeoff weight was approximately 920 kg, exceeding its maximum allowable weight of 860 kg.
Findings
- The primary cause of the accident was the jamming of the control stick by a foreign object.
- A photographer's camera, which had been placed on the front passenger seat, had slid onto the cabin floor and became wedged under the control stick.
- The design of the cockpit, specifically the ability to fold the front seats forward, increased the risk of items falling into the footwell and obstructing the controls.
- The pilot failed to ensure that all loose items in the cockpit were secured before departure.