What happened
On 17 February 2013, a private flight departing from Benston Farm, near Cumnock, experienced a significant in-flight incident. Approximately ten minutes after takeoff, the pilot of the Zenair CH 601UL Zodiac, registration G-CBAP, experienced a sudden event that felt like an explosion. The pilot quickly identified that the aircraft's canopy had detached from the cockpit.
Following the detachment, the pilot lost several items of personal equipment, including a headset, spectacles, a navigation chart, and one of two GPS units. Unable to clearly read distances on the remaining GPS due to the loss of his glasses, and noting that the rudder control felt abnormal, the pilot decided to perform a forced landing. He descended to approximately 500 feet and reduced speed to 60 knots to avoid buildings.
As the pilot approached Cumnock, he selected a field for landing. However, the ground was more saturated and rougher than anticipated. During the landing, the aircraft's nose landing gear collapsed, causing the plane to slide to a halt on its nose. The aircraft sustained damage beyond economic repair, including damage to the rudder and right elevator caused by the impact of the departing canopy. The pilot escaped the accident without injury.
The investigation
The investigation focused on the mechanical failure of the canopy latching mechanism. On this specific aircraft, the canopy was secured by longitudinal tubes held by hooks on the cockpit sills, with additional sliding bolts at the front. The investigation examined the possibility of a foreign object interfering with the rear hooks or wear within the mechanism.
Physical examination of the wreckage revealed that while the right side of the canopy had torn away, the longitudinal tube on that side was missing, even though the hooks and the front pin appeared to be in the locked position. The investigation also noted that the latching hardware on G-CBAP differed from the standard builder's manual, specifically regarding the placement of the unlatch handles.
Findings
- The canopy detachment occurred approximately ten minutes into the flight.
- The pilot's vision was significantly impaired following the loss of his spectacles during the event.
- The unlatching of the left rear canopy hook was identified as the likely initiating event for the canopy's separation from the airframe.