What happened
On 16 February 2002, a Rutan Varieze, registration G-SKCI, was performing its first flight following recent construction. After completing comprehensive pre-flight checks, the pilot took off from Biggin Hill Airport and maintained an altitude of 50 feet to verify control functionality. Upon transitioning to a climb at full power, the engine experienced an initial loss of power, which was rectified by applying carburettor heat.
As the aircraft climbed to an altitude between 400 and 500 feet, the pilot initiated a left turn to remain near the airfield. During this manoeuvre, the engine lost power a second time. Although the pilot attempted to rectify the issue by turning the carburettor heat off, the engine ceased operation entirely. The pilot issued a 'Mayday' call and turned downwind to attempt a forced landing. The aircraft touched down approximately 30 metres short of the runway threshold. Due to the soft nature of the ground, the small wheels sank, causing the nose landing gear to collapse and resulting in substantial damage to the nose of the aircraft. The pilot escaped the incident with no injuries.
The investigation
Investigators examined the aircraft for mechanical defects following the incident. The inspection found no significant faults, noting only a negligible amount of debris within the engine fuel filter drain, which the pilot believed was insufficient to cause the engine failure. The investigation also reviewed the environmental conditions, noting a surface temperature of +7°C and a dew point of 0°C.
Findings
- The engine was susceptible to carburettor icing due to its specific installation.
- Environmental conditions, characterized by 61% relative humidity and a temperature of +7°C, fell within the parameters for serious icing risk.
- The pilot had previously experienced carburettor icing during ground running in a different aircraft of the same type earlier that day.