What happened
On 7 April 2003, a Cessna 310J, registration N1158V, was performing a private flight from Sandtoft Airfield, Humberside. During the takeoff roll, the right-side main cabin door opened and began moving in the slipstream. The aircraft successfully climbed to approximately 400 feet and performed a standard left-hand turn. However, while flying at a very low airspeed, the aircraft entered a steep left turn, which appeared to be corrected, only for the right wing to drop immediately after. The aircraft then entered a right-hand spin and impacted the ground in a near-vertical attitude. The pilot, who was the sole occupant, sustained fatal injuries, and the aircraft was destroyed.
The investigation
The AAIB investigation examined the wreckage, the door mechanism, and the cockpit ergonomics. The investigation confirmed that the cabin door was found unlatched, with the external handle in the upward, unlocked position. There were no mechanical defects found in the door's locking or latching components. Engine examinations revealed no evidence of failure, and both engines appeared to have been operating normally during the initial climb.
An ergonomic assessment was conducted using a 3D computer model to simulate the pilot's movements. The study established that reaching across the cockpit to the right-side door from the left seat significantly obstructed the pilot's view of forward flight cues, reducing situational awareness. Furthermore, the physical act of reaching for the handle could cause involuntary pressure on the rudder pedals or the control yoke, potentially inducing unstable flight characteristics.
Findings
- The aircraft's cabin door was not properly secured prior to takeoff, likely due to the pilot's focus on power checks and a potential oversight in his personal checklist.
- The pilot likely lost control of the aircraft due to unintended control inputs and a loss of situational awareness while attempting to close the open door.
- Reaching for the door handle caused the pilot to lose visual references and likely resulted in inadvertent rudder or aileron movements.
- The low airspeed maintained during the attempt to close the door, combined with the aerodynamic disturbances from the open door, made the aircraft susceptible to a wing drop and subsequent stall/spin.