What happened
On 23 June 2005, a DG-800B glider, registration G-MSIX, was conducting a private flight near the West Trading Estate, south of Gloucester. The flight began as a self-launching operation using the aircraft's own engine power. During the climb, the pilot observed high engine coolant temperatures. After reaching an altitude of approximately 1,200 ft, the pilot decided to terminate the flight due to difficult soaring conditions caused by extreme heat.
While attempting to return to the airfield under power, the engine high-temperature warning light activated after the aircraft reached 600 ft. The pilot subsequently performed a landing in a hay field using a 60 kt approach speed with 8 degrees of positive flap. The touchdown was a high-impact event that caused the landing gear to collapse. The aircraft then ground-looped through ruts in the field before coming to a rest. There were no injuries to the pilot.
The investigation
Investigators examined the engine and the radiator assembly following the accident. Post-accident inspections revealed significant white staining around the radiator filler, suggesting a loss of coolant during flight. A maintenance engineer noted that the radiator's position within the mast makes the filler cap difficult to secure properly. It was suggested that the cap might have been incorrectly installed, which would allow coolant to escape under pressure.
Findings
- The engine experienced a high-temperature event during the flight.
- The landing gear collapsed due to the high-impact nature of the landing and the aircraft running over a rut in the field.
- Improperly securing the radiator filler cap may have allowed coolant to escape under pressure, leading to the engine overheating.