What happened
On 30 June 2015, a Practavia Sprite Series 2, registration G-BCVF, was performing a private flight from Tatenhill to Earls Colne, with a planned stop at Sywell. During the initial climb, the pilot observed that the engine temperature was abnormally high and the oil pressure was low. In an attempt to cool the engine, the pilot levelled off, but the readings failed to stabilise. Consequently, the pilot decided to divert to Bruntingthorpe Aerodrome.
While en route to the diversion airfield, a portable carbon monoxide monitor in the cockpit triggered an audible alarm. Seeking to ventilate the cockpit, the pilot opened the sliding canopy. This action caused the canopy to detach from the airframe. Despite the loss of the canopy, the pilot managed to land the aircraft safely at Bruntingthorpe. There were no injuries to the pilot, and no damage was reported on the ground.
The investigation
The AAIB investigation examined the mechanical state of the aircraft and the circumstances leading to the canopy loss. The investigation found that the engine exhibited a large crack in the casing, which was identified as the likely source of both the poor engine performance and the carbon monoxide fumes.
Regarding the canopy, the investigation established that the assembly on this specific aircraft type is only secured to the airframe when it is fully closed. There was no evidence suggesting that the recent replacement of the canopy contributed to its detachment. Furthermore, an inspection by the Light Aircraft Association (LAA) following the event raised concerns regarding the general maintenance of the aircraft, including the presence of a prohibited PVC fuel hose in the fuel system.
Findings
- A large crack in the engine casing caused the engine temperature to rise and the oil pressure to drop.
- The engine crack was also the likely source of the carbon monoxide fumes detected in the cockpit.
- The canopy detached because it was not secured to the airframe while in the open position.
- The pilot's decision to open the canopy was prompted by the need for ventilation following the carbon monoxide alarm.