What happened
On 8 September 2015, a Cyclone AX20 and registration G-BYJM was conducting a private flight from Clench Common. While passing Manton Airfield at approximately 1,100 ft, the pilot noticed the aircraft was struggling to maintain its altitude. Suspecting atmospheric sink, the pilot opted to land at Manton for a precautionary inspection. After finding no visible issues with the engine or airframe, the pilot performed a solo circuit, which proceeded normally, leading him to believe the initial difficulty was indeed due to sinking air.
Upon attempting to return to Clench Common with a passenger, the aircraft encountered a second period of insufficient climb performance. During the climbout, at roughly 200 ft above ground level, the airspeed began to decay. The pilot initiated a forced landing into a recently harvested wheat field. During the turn toward the field, the right wing dropped sharply, likely due to a stall. While attempting to land downwind on a grass field to the south, the pilot closed the throttle to avoid impacting the rising terrain. This action, combined with a high groundspeed and an attempt to flare, resulted in a stall. The aircraft struck the ground, causing significant damage to the fuselage and landing gear.
The investigation
The investigation focused on the apparent loss of engine performance and the sequence of the forced landing. Investigators examined the engine and airframe for any mechanical defects that could explain the inability to maintain altitude. No specific cause was identified to explain why the engine might have failed to deliver full power. The investigation also reviewed the pilot's actions during the final moments of the flight, specifically the decision to close the throttle while facing rising terrain and the subsequent stall.
Findings
- The two occupants sustained minor injuries.
- The aircraft sustained substantial damage, including a snapped fuselage tube, a collapsed landing gear, and a broken forward compression strut.
- The pilot did not monitor the RPM gauge during the flight to verify if the engine was producing full power.
- The pilot's decision to close the throttle while approaching rising ground, combined with the high groundspeed of a downwind landing, contributed to the loss of airspeed and the subsequent stall.