The pilot was performing what he considered as “light aerobatics” in an area to the north of Billericay in fine weather conditions. At the bottom of a “normal loop” he reported encountering wake turbulence, after which the aircraft rolled left. The pilot recovered the aircraft to a wings-level attitude, but noted that some fabric had separated from the forward area of the top left wing.
After performing a control check in the approach configuration, the pilot considered the aircraft controllable enough to perform a normal landing, despite a “marked rolling tendency”. The aircraft landed successfully and was subsequently inspected by the LAA who discovered a failure of the affected wing’s leading edge structure. They considered the most likely cause was the result of previous damage to the leading edge which may have been small enough to be unnoticed during pre-flight walkaround checks. This damage had then progressed during the higher energy aerobatic manoeuvring. The source of this previous damage could not be established.
The LAA reported this event in further detail in their February 2017 edition of Safety Spot magazine which is available on their website. They highlighted that the area in question could not be inspected without a step ladder and that thorough pre-flight inspections of all aircraft surfaces is extremely important.