What happened
On 10 March 1999, a Reims Cessna FA152 Aerobat, registration G-BIHE, was conducting aerial photography near Sheerness, Isle of Sheppey, Kent. The flight had originated from Sibson Airfield, Cambridgeshire, and was en route to the Canterbury area for further photographic work.
While flying at 1,500 feet agl over the mouth of the River Medway, the engine suddenly and smoothly ran down. The pilot, attempting to manage the failure, noted intermittent fuel starvation and found that pumping the throttle could briefly restore power. After transmitting a Mayday call to Southend Airport, the pilot attempted a 180-degree turn to land into the wind. However, due to insufficient altitude and power, the aircraft could not complete the turn and was forced to land straight ahead into a field with a rough surface.
During the landing, the nosewheel detached upon impact with the uneven ground. The aircraft subsequently nosed over, coming to rest inverted. The impact caused the nose landing gear to detach, the fuselage to distort, and the right wing to sustain severe damage. The pilot sustained minor injuries, specifically severe bruising to the ribs, but was able to exit the aircraft unaided.
The investigation
The investigation involved an examination of the aircraft and the engine by an overhaul agency. The engine was subsequently tested on a test bed, where it was found to operate normally and produce the required maximum output power. No defects were found in the carburettor, the magneto settings, or the spark plugs. Additionally, the carburettor heat system was found to be functioning correctly, as evidenced by the ability to manually manipulate the air supply.
Findings
- The engine power loss was likely caused by induction system icing.
- Atmospheric conditions at the time, specifically the cloud base and humidity levels, were conducive to the formation of ice within the engine's induction system.
- There was no evidence of mechanical failure, fuel starvation from the tanks, or deficiencies in the aircraft's maintenance or carburettor heat system.
Safety action
- Recommendation 2000-55: The CAA was advised to assess available induction system icing warning systems and consider requiring their installation on UK registered aircraft susceptible to sudden power loss due to such icing.