What happened
On 30 May 2006, a Cessna F172M, registration G-BAOS, was conducting a private cross-country flight from Hawarden, Cheshire, to Seething Aerodrome, Norfolk. While approaching the airfield, the pilot flew over the site at 800 ft to assess wind conditions and runway alignment. The pilot then transitioned to a right base for Runway 06.
During the go-around procedure, the pilot applied full power and set the carburettor heat to the cold position. As the aircraft climbed, a reduction in engine power was noted. In an attempt to maintain airspeed, the pilot lowered the nose and applied carburettor heat. Despite the application of heat, the engine power continued to diminish. The pilot initially delayed a forced landing, attempting to fly the aircraft while hoping power would be restored, and maneuvered toward a downwind position to survey potential landing sites.
As the power loss became critical, the pilot identified a suitable field. However, upon approaching the site, the passenger alerted the pilot to the presence of power lines. The pilot maneuvered away from the lines and closed the throttle to land in an alternative field. The landing area contained a damp, standing crop, which caused the aircraft to decelerate abruptly and pitch forward, resulting in the aircraft coming to rest inverted. Both the pilot and the passenger sustained minor injuries.
The investigation
Investigators examined the atmospheric conditions at the time of the accident. Data from the nearby Norwich Airport indicated a temperature of 8ºC and a dewpoint of 6ºC, with recent rain showers in the area. These conditions were identified as being highly conducive to the formation of carburettor ice.
Findings
- The primary cause of the engine power loss was carburettor icing.
- The pilot's decision to continue flying in the hope of power recovery, rather than committing to an immediate forced landing, contributed to the sequence of events.
- The aircraft sustained substantial damage during the landing.
- The presence of a damp, standing crop in the landing field contributed to the rapid deceleration and subsequent inversion of the aircraft.