What happened
On 12 March 2000, a Europa aircraft, registration G-KWIP, was involved in an accident at Hollymeadow Farm, Bradley, Derbyshire. During the climbout phase of the flight, witnesses on the ground observed light grey or blue smoke emerging from the engine cowling, accompanied by a noticeable reduction in engine power. This loss of power subsequently led to a loss of control, resulting in the aircraft impacting the ground.
The investigation
Initial investigations into the accident focused on a coolant hose segment that had disconnected from the radiator's bottom spigot. While early assessments suggested the hose might have been oversized, subsequent research and instrumented testing provided a different explanation.
Tests conducted on new hoses and the overflow bottle revealed that the cooling system was subject to extreme conditions. It was determined that the hose had not been incorrectly installed, but rather had stretched and enlarged due to high temperatures and pressures. Specifically, the internal pressure reached levels sufficient to force the hose off its connection point. Furthermore, while the overflow bottle showed signs of bulging from pressure, the actual split in its seam was found to be a result of the impact with the ground rather than a pre-impact failure.
Findings
- The primary cause of the power reduction was the ingestion of coolant vapour and spray into the engine's carburettor intakes following the hose disconnection.
- The disconnection was caused by excessive temperature and pressure within the cooling system, which caused the hose to expand and eventually slip off the metal fitting.
- The coolant concentration was approximately 50%, which was consistent with manufacturer recommendations at the time.
- The failure of the overflow bottle seam occurred during the impact with the ground, caused by the component being driven against its fixings.