On 18 March 2022 the owner / pilot in command (PIC) of Extra NG2 aircraft had planned aerobatic flights from EPKP airfield. After pre-flight inspection and main tank refuelling up to ca. 70 l, he flew a solo flight – it was uneventfull. During the second flight with passenger on board, right after completing the sequence and joining the aerodrome circle, the passenger informed PIC about „unusual sounds and light vibrations of the aircraft”. Both men were convinced the sounds came from the engine, so after landing the PIC performed the engine test run, but no irregularities were found. After refuelling the main tank, the men checked the aircraft, looking for eventual loosened part causing noise and vibration observed during the second flight. The check did not reveal any failures, so the crew finally concluded, the vibration they heard and felt were an illusion only.
However, before the third take-off (the same crew), after starting-up the engine, the PIC performed additional engine check twice. No discrepancies were identified.
The take-off and climb up to 4000 ft AGL went in a standard way. PIC contacted APP Krakow (approach service) and got the clearance for entering to the control zone. After accelerating up to ca. 350 kph and levelling the flight, the canopy suddenly opened, broke and part of it detached from the aircraft. PIC immediately reduced the speed to approx. 200 kph, descended and landed uneventfully on EPKP with no radio contact. After gentle touch-down, the pilot taxied to the hangar. PIC, who was sitting in the back, suffered minor face cut, probably caused by the headset when the wind blew it away.
Most canopy parts was found in the airfield area. They did not cause injuries to third parties or material losses.
The probable cause of the occurrence was vibration of the canopy frame caused by the loss of its stiffness that led to pawls unlocking and detaching the canopy from the aircraft.
Factors contributing to the occurrence:
1. Probable crack of canopy frame in the flight before the occurrence (or earlier);
2. Loosened rear fitting of the canopy locking system;
3. Accelerating the aircraft to a high speed, close to Vne.
PKBWL has not proposed any safety recommendations.
