What happened
On 29 March 2014, a Yak-52, registration G-YAKR, was conducting a short local flight from North Weald. The pilot, an experienced aviator with over 15,000 flying hours, had recently taken a passenger on board for the trip. After departing at 1447 hrs, the aircraft was initially seen climbing above 1,000 ft, but subsequent observations by witnesses near Highwood, Essex, described the aircraft flying at a very low altitude, between 100 and 200 ft agl.
Witnesses observed the aircraft performing a level turn before it climbed abruptly to approximately 400 ft agl. Following this climb, the aircraft appeared to enter an incipient spin or pitch downwards sharply, striking the ground in a steep, nose-down attitude. The impact triggered a severe post-crash fire. Both the pilot and the passenger sustained two fatal injuries.
The investigation
The AAIB examined the wreckage and the engine components. Although the intense fire destroyed much of the cockpit and the carburettor, investigators were able to analyze the accessory gearbox and the propeller. The investigation found that the engine was still rotating at the time of impact, though it may have been producing low power. The propeller blades showed evidence of bending due to the impact rather than pre-impact failure.
Medical examinations and toxicological tests were conducted on the occupants. The investigation also reviewed the pilot's medical history, specifically his management of diabetes, and found no evidence that his health condition contributed to the accident. Furthermore, no defects were identified in the surviving portions of the flight control systems.
Findings
- The aircraft's final manoeuvre, which resulted in a stall or spin, could not be definitively explained.
- The aircraft was flying at an unusually low altitude during the final stages of the flight.
- There was no evidence to suggest the pilot's diabetes played a role in the accident.
- The engine was operational at the moment of impact, though a significant loss of power cannot be ruled out.