What happened
On 14 April 2005, a Piper PA-18-150 Super Cub, registration G-BGWH, was engaged in a training flight involving a student refresher course. The flight, which began at Clacton Airfield, included a planned stop at Nayland Airfield. During the takeoff roll from Nayland's damp, undulating grass runway, the aircraft drifted left as it crested a rise. The left main landing gear exited the runway surface and moved onto a sloping shoulder, where the aircraft struck an earth mound obscured by vegetation. This impact caused damage to the right main landing gear.
After becoming airborne, the instructor assessed the aircraft's condition from the rear cockpit. While the engine, propeller, and left gear appeared intact, the condition of the right gear was not clearly visible. The decision was made to return to Clacton Airfield. Upon arrival, a low fly-by allowed for a visual inspection by ground personnel, which confirmed that the right main landing gear had been bent.
As the aircraft prepared to land at Clacton, emergency services were placed on standby. The instructor attempted a landing technique designed to keep the right wing elevated using aileron input, effectively attempting to land on the left gear alone. However, upon touchdown, the left main landing gear collapsed under the aircraft's weight, causing the plane to slide on its belly until it came to a halt.
The investigation
The investigation established that the initial damage occurred due to the aircraft's movement off the runway centerline during takeoff at Nayland. Following the impact with the earth mound, the crew sought an inspection at Clacton. While the air ambulance crew on site confirmed damage to the right gear, the instructor proceeded with landing attempts. The investigation examined the sequence of the landing at Clacton, noting that the collapse of the left gear was the direct result of the weight being placed on the already compromised landing gear structure during the touchdown.
Findings
- The aircraft's left main landing gear exited the runway runway surface at Nayland due to the aircraft drifting left while traversing an undulation.
- The impact with a hidden earth mound at Nayland caused the initial bending of the right main landing gear.
- The left main landing gear collapsed during the landing at Clacton because the aircraft was landed specifically on that gear to avoid further damage to the right side.