What happened
On 12 July 2020, an Easy Raider 503(1), registration G-SRII, was conducting a private flight from Baxby-Hustwaite Airfield to Sturgate Airfield and back. During the return leg of the journey, while cruising at approximately 1,800 ft agl, the Rotax 503-DCDI-2V engine began running roughly before completely seizing. This resulted in a total loss of engine power.
The pilot declared a MAYDAY and identified a suitable field for an emergency descent. The aircraft completed a forced landing in a furrowed crop field near Dunnington, York. While the pilot escaped the aircraft without injury, the aircraft sustained significant damage to the propeller, landing gear, tail, and fuselage due to the uneven terrain.
The investigation
The AAIB investigation established that the engine failure was caused by a lack of lubrication. Before departure, the pilot had prepared two 20-litre jerry cans of Mogas. To avoid storing fuel in the hangar, the pilot measured the two-stroke oil in the hangar and then walked to the fuel cans to add the oil. During this process, a lapse in concentration led the pilot to add both required doses of oil to the first can, leaving the second can with no oil.
Upon arriving at Sturgate Airfield, the pilot topped up the aircraft's tanks using the unlubricated fuel from the second can. Because the pilot had to reach up from the ground to fill the tanks without a ladder, he was unable to visually inspect the fuel for the presence of the characteristic two-stroke oil dye.
Findings
- The engine seized because of insufficient lubrication caused by the omission of two-stroke oil in the fuel.
- A lapse in concentration during the fuel preparation process resulted in both doses of oil being added to only one of the two jerry cans.
- The method of refueling from ground level prevented the pilot from noticing the absence of oil dye in the fuel.
- The successful outcome of the forced landing was attributed to the pilot's proactive habit of identifying potential landing sites and his recent training in forced landing procedures.