What happened
On 25 April 1998, a Spitfire IXT, registration G-BMSB, was conducting a pre-display test flight from Coventry Airport. Shortly after takeoff, the pilot successfully retracted the undercarriage, but encountered a malfunction when attempting to extend the gear. The undercarriage lever could not be moved into the full DOWN position, leaving the wheels locked in the up position.
Despite multiple attempts to manipulate the lever under varying flight loads, the gear remained stuck. The pilot opted against using the pneumatic blow-down system to avoid the risk of the gear becoming unlatched or stuck in an unsafe, partially extended state. To mitigate risk, the pilot instructed the rear occupant to secure their harness and partially open the canopy, while the pilot jettisoned the front canopy. The aircraft performed a power-unassisted, full-flap landing on the grass at Coventry. The aircraft touched down at 65 kt and slid on its belly for approximately 100 yards. There were no injuries to the two crew members.
The investigation
Investigators examined the aircraft's hydraulic and mechanical systems. While initial inspections suggested the undercarriage selector was functioning normally, investigators discovered a small aluminium electrical cable guide block, measuring roughly 3/8 of an inch, on the floor of the rear cockpit. This block had originally been secured near the top of the undercarriage selector by a screw that had loosened.
On this specific aircraft, which had undergone electrical rewiring, the block was redundant. It was determined that the loose block had fallen into a position where it could physically block the movement of the selector lever. Evidence on the block indicated it had been caught in the mechanism before likely falling out of the selector during the impact of the landing.
Findings
- The primary cause of the undercarriage failure was the obstruction of the undercarriage selector lever by a loose aluminium cable guide block.
- The block became unseated because its retaining screw had come undone.
- The aircraft sustained damage to the propeller, engine cowling, carburettor air intake, and radiator fairings.
Safety action
Following the incident, a Mandatory Permit Directive (MPD) No.1998-008 was issued by the CAA for all Spitfires and Seafires operating under a UK Permit-to-Fly. This directive required inspections to ensure all such blocks were either firmly secured or removed and replaced with appropriate hardware to prevent recurrence.