What happened
On 27 June 2016, a Piper PA-28-161 Cherokee Warrior III, registration G-BZDA, was returning to White Waltham Airfield in Berkshire following a local training flight. During the final approach phase, the aircraft's engine lost power. In response to the loss of thrust, the instructor performed a forced landing in a field located short of the runway.
While the aircraft sustained significant damage to the engine, propeller, engine bearer, nose landing gear, and lower firewall, there were no injuries to the two crew members on board. At the time of the incident, weather conditions were favorable, characterized by a temperature of 20°C and a dew point of 13°C, with scattered clouds at 3,500 ft.
The investigation
The investigation examined the mechanical state of the aircraft and the atmospheric conditions present during the flight. Following the recovery of the aircraft, the maintenance organisation tested the engine and determined that it was operating normally.
Investigators analyzed the meteorological data using the CAA icing conditions chart from ‘Safety Sense Leaflet 14, Piston Engine Icing’. By plotting the recorded temperature and dew point, it was determined that conditions were conducive to moderate icing at cruise power and serious icing at descent power. The instructor noted that despite the application of carburetor heat for the duration recommended in the Pilot’s Operating Handbook, icing had likely accumulated in the carburetor.
Findings
- The engine lost power during the final approach to the airfield.
- Atmospheric conditions indicated that carburetor icing was a significant risk, with the potential for serious icing during descent.
- The engine was found to be mechanically functional during post-accident testing.