What happened
On 1 August 2022, a Zenair CH 601UL, registration G-CDAL, was performing a private flight departing from Runway 24 at Fife Airport. Shortly after takeoff, while climbing through an altitude of approximately 100 to 150 feet, the right side of the aircraft canopy lifted open. This event was accompanied by a loud noise and a sudden influx of air that dislodged the pilot's headset.
The resulting aerodynamic drag and handling difficulties forced the pilot to perform an immediate forced landing in a field of barley located northwest of Kinglassie. During the landing roll, the aircraft encountered thick crops that caught the undercarriage and wings. This caused a rapid deceleration and a loss of directional control, resulting in significant damage to the fuselage, wings, propeller, canopy, and undercarriage. The pilot sustained minor injuries.
The investigation
Investigators examined the aircraft's canopy design, which utilizes independent latching mechanisms on both the pilot and passenger sides. These latches engage with spigots on the cockpit sills when the canopy is closed. While the pilot had performed routine security checks before departure, it was noted that the design of the spigot bracket and seat back prevented a visual confirmation of the passenger-side latch engagement.
Post-accident inspections of the latching mechanisms found no mechanical faults. However, the left cockpit sill showed signs of distortion near the latch spigot bracket. The pilot's own inspection revealed that the latch operating linkage could be released by upward pressure on the linkage itself, independent of the handle. This indicated that if the linkage were obstructed during the closing process, the latch jaws might fail to secure properly around the spigot.
Findings
- The primary cause of the accident was the right canopy latch failing to fully engage the spigot, allowing the canopy to lift under aerodynamic loads.
- It is believed that an object likely fouled the latch operating linkage while the canopy was being closed, preventing a secure lock.
- The sudden inrush of air and the resulting structural torsion may have caused the left side of the canopy to fragment, as evidenced by the broken and missing left canopy section.
- The rapid deceleration and subsequent damage were caused by the aircraft's interaction with the barley crop during the forced landing.