What happened
On 7 September 2015, a Vickers-Armstrongs Ltd Spitfire T9, registration D-FMKN, was conducting a private flight from Woodchurch, Kent, toward Biggin Hill Airport. While cruising at approximately 1,200 ft agl, the pilot adjusted the engine settings to 2,000 rpm and a +1 boost. Shortly after this adjustment, the pilot noticed a drop in engine power. Although engine gauges and controls appeared normal, attempting to increase the throttle led to engine misfires and backfires. The engine would only operate reliably at idle speeds, prompting the pilot to initiate an emergency return to Woodchurch.
Realising the aircraft could not reach the airfield, the pilot selected a large field near Woodchurch for a wheels-up forced landing. While the landing itself was successful, the soft, stubble-covered ground caused the underwing radiator units to dig into the soil. The intense drag created by this impact caused the left wing to detach at its root.
The investigation
The investigation focused on the engine's failure to maintain power and the subsequent structural damage during the landing. Investigators examined the engine's performance following the pilot's attempt to adjust the throttle and the physical impact of the landing on the aircraft's airframe. The investigation confirmed that the pilot had no injuries following the incident.
Findings
- The engine experienced a loss of power following a throttle adjustment, characterized by misfires and backfires.
- The engine was only capable of running smoothly at idle settings.
- The underwing radiators digging into the soft soil during the forced landing created enough drag to detach the left wing from the aircraft root.
- The aircraft sustained damage to the propeller and the underwing radiator units.