Aircraft and Flight Details
On 18 July 2015, a Spitfire Mk 26 (80% scale replica), registration G-CENI, was involved in an accident at Peterborough Sibson Airport, Cambridgeshire. The aircraft was manufactured in 2007 and powered by a single Jabiru 5100A piston engine. The flight was a private operation with the sole occupant being the pilot, who held a Private Pilot's Licence and had 388 hours total flying experience, including 26 hours on type. The pilot was uninjured.
Circumstances of the Accident
The pilot had flown earlier from Sibson to Peterborough Connington and was returning. After takeoff, the landing gear was retracted with normal indications. While joining the downwind leg at Sibson, the pilot slowed the aircraft within the gear deployment airspeed range and moved the cockpit panel switches for each main gear to the down position. The left gear indicator showed a green light (indicating down), but the mechanical indicator on the left wing showed the gear remained up. The pilot then operated both gear levers in the normal manner. The right indicator turned red (gear travelling) and then showed down, but the left gear did not extend. The pilot requested a go-around and a visual check from the tower, which confirmed the right gear was down and the left was retracted. Multiple attempts to recycle the gear using positive g-forces failed. The pilot also deployed the emergency gear release system for the left gear, but it did not deploy.
With the engine oil temperature elevated due to prolonged low-speed operation, the pilot increased power and circled to burn fuel while emergency services positioned themselves. He opted to use power and flaps for the approach, considering the thermal and gusty conditions on Runway 24L. After a low-level go-around to assess the grass runway, the pilot retracted the canopy and approached at about 55 kt, reducing to 45 kt. The aircraft touched down on the stall and slid approximately 10 m before stopping. The pilot shut off the fuel and battery master switch and exited uninjured.
Investigation Findings
Examination revealed that the left landing gear down microswitch was stuck, preventing the electrical circuit from completing when the lock lever was moved, thereby inhibiting the motor from extending the gear. Additionally, the left landing gear leg was found to be slightly bent, likely from a previous heavy landing or excessive side load. This caused the wheel to press against the underside of the wing skin, creating tension in the system. The emergency release did not work because, after removing the connecting pin, the gear did not move under gravity and spring assistance due to this tension. Adjusting a rod end by one turn relieved the tension and allowed the emergency system to function as designed.
Following the accident, the Light Aircraft Association (LAA) advised all owners of this aircraft type to conduct drop tests of the emergency gear system with the aircraft on jacks. The LAA also noted that later Mk 26 kits incorporated more robust main gear legs, and the Mk 26 kit has since been replaced by the Mk 26B, a 90% scale version.
Aircraft Description
The Spitfire Mk 26 is a conventionally configured low-wing monoplane, an 80% scale replica of the wartime fighter. It is manufactured as a kit in Australia for amateur construction and administered in the UK by the LAA. The main landing gear legs are independently raised and lowered by electrically powered rams, with locking pins operated by Teleflex-type cables. Emergency lowering is achieved by pulling a cable that ejects a connecting pin, allowing gravity and spring assistance to extend the gear.