What happened
On 12 September 2009, a Grob G115E Tutor, registration G-BYWH, was participating in a three-aircraft formation landing at RAF Leeming, North Yorkshire. The flight was part of a planned military display for a station families' day. During the rollout of a 'stream' landing on Runway 16, the pilot of the trailing aircraft, G-BYWH, observed the second aircraft in the formation moving across the runway centerline. To prevent a potential collision, the pilot applied maximum, continuous brake pressure.
This intense braking caused the wheels to lock up, resulting in a skid and significant nosewheel shimmy. The crew reported hearing two loud cracks originating from the main landing gear. While the aircraft did not collide with the preceding aircraft, the sudden deceleration and resulting forces caused the landing gear rib and lower wing skin to fail under overload. There were no fatalities and no injuries to the crew.
The investigation
The AAIB investigation examined the aircraft's structural integrity and the operational circumstances of the landing. Physical inspection of G-BYWH revealed significant cracking in the lower wing skin and between the gear rib and the wing rib and root rib. The investigation also reviewed the manufacturing processes of the composite components.
Analysis of the adhesive used in the wing joints showed high levels of porosity and excessive thickness, which exceeded the manufacturer's design specifications. Furthermore, the investigation looked into the flight planning and the decision-making process of the flight crew during the formation landing, noting that the pilots were managing high workload and timing pressures related to a scheduled Royal Flight.