What happened
On 27 April 2013, a replica Fokker EIII, registration G-CHFS, was participating in a practice air display at Middle Wallop Airfield in Hampshire. The aircraft was part of a group of seven vintage-style replicas performing training maneuvers. During the second practice session of the day, the aircraft was flying at a low altitude, approximately 200 feet, as part of a sequence involving simulated attacks on another aircraft.
While attempting to turn right to align with a simulated crowd line, the aircraft entered a steep descent. Witnesses observed the aircraft turning through approximately 180 degrees before it began to lose altitude rapidly. The aircraft completed roughly two full rotations while descending in a near-vertical attitude, eventually striking the ground at the south-west end of the airfield. The impact triggered a significant post-crash fire that destroyed the aircraft. The pilot, who was the sole occupant, sustained fatal injuries.
The investigation
The AAIB investigation examined the aircraft's construction, flight history, and handling characteristics. The G-CHFS was a modern, full-scale replica built with a steel tube fuselage and wooden wing structures, powered by a 145 hp Warner Scarab engine. The investigation reviewed the pilot's experience, noting that while highly skilled, he had limited recent experience on this specific type.
Engineers examined the wreckage and found that the primary structural connections and control cables were intact. The engine was found to be under power at the moment of impact. The investigation also looked into the aircraft's unique wing-warping roll control system and the use of a control column clamp, which was used to manage the aircraft's high pitch sensitivity.
Findings
- The aircraft's wing-warping system provided roll control but had limitations regarding roll rate reversal.
- The aircraft had a tendency to develop large slip angles due to reduced dihedral effect and relaxed directional stability.
- The aircraft likely entered a sideslip during the turn, leading to a roll rate that exceeded the capability of the wing-warping system to correct.
- The pilot's attention may have been focused on maintaining the display line rather than monitoring the slip indicator.
- The pilot's recent flying experience on this specific aircraft type was limited.