What happened
On 17 September 2009, a Luton LA4A Minor, registration G-ASEB, departed from Seige Cross Farm airstrip for a private flight. The aircraft, a single-seat homebuilt model, began its takeoff and initial climb normally. However, approximately 15 seconds into the climb, the pilot observed a reduced climb rate, an airspeed roughly 10 knots lower than expected, and engine speeds fluctuating about 100 rpm below normal.
At an altitude of approximately 100 feet, the engine ceased operation just as the pilot attempted to engage the carburettor heat. To avoid an approaching barn, the pilot banked the aircraft to the left. Encountering a high hedge approximately 15 to 20 feet tall that appeared impassable, the pilot pulled back on the control stick to reduce forward speed and approach a stall. This maneuver resulted in the aircraft striking the ground with a high vertical descent rate and low forward velocity. The aircraft sustained damage to its propeller, landing gear, and fuselage, but the pilot escaped the wreckage with no injuries.
The investigation
The AAIB examined the engine and fuel systems following the accident. The pilot's post-flight inspection of the fuel system showed no signs of water contamination, and a fuel flow test was performed successfully. An internal examination of the carburettor revealed no foreign debris or water, and the main jet was found to be clear. The magnetos had recently been refurbished, and the spark plugs were in satisfactory condition. The engine showed no evidence of mechanical failure.
Findings
- The engine stopped due to carburettor icing.
- Environmental conditions at the time included a temperature of 14°C and 54% humidity, which placed the aircraft in a risk category for icing according to standard probability charts.
- The pilot had not used the carburettor heat during taxiing because the air and grass felt dry, though the heat had been used briefly during pre-takeoff run-up checks.