What happened
On 23 July 2019, an Extra 330SC, registration OO-SDJ, was engaged in a private aerobatic flight over Wickenby Aerodrome, Lincolnshire. Roughly ten minutes into the flight, while the pilot was executing a vertical climb, a notable vibration was felt through the left rudder pedal. In response to this abnormal sensation, the pilot immediately terminated the manoeuvre and transitioned the aircraft into level flight.
Despite reducing airspeed, the vibration persisted, prompting the pilot to conclude the flight and land. Upon post-flight inspection, it was discovered that the fabric covering the rear section of the fuselage had torn. This loose material had been flapping in the airflow on the left side of the aircraft, which disrupted the aerodynamics around the rudder and created the vibration felt in the controls. There were no injuries resulting from the incident.
The investigation
Investigators examined the aircraft to determine why the fabric had failed. The Ceconite 102 fabric was stripped from the airframe and submitted to the AAIB for analysis. The examination suggested that the failure likely began at the forward edge of the fabric panel, specifically adjacent to the right lower stringer of the tubular steel spaceframe.
It appears that an initial tear occurred both laterally and axially along the stringer, which then progressed toward the rear of the tail cone. While the physical path of the tear was identified, the investigators were unable to determine the specific reason for the initial material failure. Prior to the flight, the pilot had performed standard pre-flight checks and had not observed any existing damage to the fuselage covering.
Findings
- The vibration in the rudder pedals was caused by aerodynamic disruption from loose, flapping fabric.
- The failure likely originated near the right lower stringer of the rear fuselage.
- The cause of the initial fabric tear could not be identified.
- The pilot's decision to abort the manoeuvre was timely and prevented potential further damage or entanglement with control surfaces.