What happened
On 18 August 2009, a student pilot was conducting solo circuit exercises in a Piper PA-28-161 Cherokee Warrior II, registration G-BNXT. During the second solo circuit, while orbiting on the downwind leg as instructed by ATC, the pilot noticed the aircraft was further downwind than anticipated. Upon turning onto the base leg, the pilot observed the aircraft was slightly above the required circuit height.
At this point, the pilot selected two stages of flap, which coincided with a loss of engine heat and a reduction in power to approximately 1,700 rpm. The pilot noted that the aircraft descended more rapidly than expected and that the engine showed little response to throttle inputs. The pilot issued a mayday call and maneuvered the aircraft toward a field near residential buildings. The aircraft subsequently struck a tree at the edge of a school playing field in Bromley, Kent. The impact caused the aircraft to fall through branches and come to rest near ground level. The pilot sustained minor injuries to her legs and ankles but was able to exit the cabin through the door, which opened upon impact.
The investigation
The AAIB examined the engine and found no mechanical malfunction or defect to explain the reported loss of power. Radar and radio recordings confirmed a descending right turn ending in ground impact. Investigators also analyzed the environmental conditions, noting a temperature of 20°C and a dewpoint of 13°C.
Findings
- The engine was found to be in working order with no identifiable fault.
- Atmospheric conditions were conducive to carburettor icing, which could explain the power loss and lack of throttle response.
- The pilot's landing was performed downwind, resulting in a higher groundspeed at the moment of impact.
- The student pilot had limited experience with in-circuit engine failure procedures, having previously only practiced engine failure drills during the initial climb after takeoff.