What happened
On 24 June 2000, a private flight involving a Jabiru 330 and registration G-OKPW was underway from Shoreham Airfield toward Cranfield. After a successful departure from Runway 21, the aircraft reached a cruising altitude of 1,600 feet and a speed of 120 kt. Approximately eight minutes into the flight, the right-hand gull-wing door suddenly opened and detached from the airframe.
The pilot responded by reducing the airspeed to 80 kt. Despite the loss of the door, the aircraft remained controllable, and no damage to the tail unit was observed. The pilot declared a PAN-PAN call on the Shoreham frequency, requesting an immediate landing on the most into-wind runway. The approach controller cleared the aircraft to join the downwind for Runway 03. During the landing, the aircraft experienced one or two bounces before the pilot regained full control and taxied back to the airfield without further issues. There were no injuries to the two persons on board.
The investigation
The investigation focused on the mechanism of the gull-wing doors, which were hinged at the top and secured via spring-loaded latch pins operated by cables. The pilot had performed a pre-flight check to ensure the pins were visibly protruding through the door frame.
Investigators examined the door's design, noting that the hinging arrangement allowed airflow to potentially disengage the hinges if the door opened wide in flight, leading to a clean separation. The investigation also looked into the reliability of the latching system, specifically the reliance on tension cables to retract the pins.
Findings
- The investigation could not find a definitive reason why the door became unlatched.
- The design of the latching mechanism relied on tension cables to withdraw the pins against their springs.
- The cable system allowed the operating handles to return to a closed and locked appearance even if the pins had failed to engage the door frame, as any lack of engagement was masked by slack in the cables.
- The loss of the door resulted in minor damage to the door sill, though the door itself was never recovered.