Occurrence Details
On 18 March 2022, a serious incident involving an Extra NG aircraft, registration SP-HMM, occurred at Kraków-Pobiednik aerodrome (EPKP). The aircraft was operated privately and was conducting aerobatic flights. The pilot-in-command, a 48-year-old male holding a valid PPL(A) with aerobatic endorsement, occupied the rear seat. A passenger, also a pilot, was seated in the front and was not involved in aircraft control.
Flight History
The pilot had completed an uneventful solo flight earlier. During a subsequent flight with the passenger, abnormal sounds and light vibrations were noted, attributed initially to the engine. After landing, an engine run-up and visual inspection revealed no discrepancies. For the third flight, the pilot performed additional engine checks.
During the third flight, after take-off and climbing to 4000 ft AGL, the pilot accelerated to approximately 350 kph. The canopy suddenly opened, broke, and partially detached from the aircraft. The pilot immediately reduced speed to about 200 kph, descended, and landed at EPKP without radio contact. After landing, he taxied to the hangar.
Injuries and Damage
The pilot sustained minor injuries, specifically a facial cut likely caused by his headset being blown away by the wind. These injuries did not require advanced medical treatment. The passenger was uninjured.
The aircraft suffered damage from the canopy detachment. The canopy opened on its hinges, struck the right upper wing skin, and shattered. A portion of the canopy frame remained on the starboard side, while debris fell to the ground. The vertical fin, rudder, and right side of the horizontal stabilizer sustained minor damage including dents and scratches.
Investigation and Analysis
The investigation was conducted by the State Commission on Aircraft Accidents Investigation (PKBWL). The aircraft was not equipped with recording devices. Analysis relied on statements from the pilot, passenger, and ground staff, as well as photographs of the damage.
Examination of the canopy locking mechanism revealed that the rear fitting on the portside had loosened screws. This created a clearance between the fitting and the fuselage, which could have caused canopy vibrations. The pushrod connecting the pawls was found slightly bent, likely from the stress of the canopy detaching. The pawls themselves were found in the locked position after the event, but the investigation determined they must have been open at the time of detachment, then returned to locked by spring force.
The pilot stated that the canopy was properly locked before take-off. The investigation considered this credible because an unlocked canopy would likely have detached during engine run or taxi. The unintentional opening of pawls in flight was excluded as a cause. The loosened screws were identified as a potential source of vibration that may have led to the canopy unlocking in flight.
Probable Cause
No probable cause was explicitly stated in the report.
Safety Recommendations
No safety recommendations were issued.