Incident Overview
At the beginning of its takeoff roll, a Cirrus SR20 experienced a jam of the aileron and rudder controls. The student pilot applied full right rudder while simultaneously applying full left aileron, which caused the controls to lock. No prior control problems had been reported since the airplane was delivered new. Review of maintenance records showed no previous control issues or re-rigging of the flight control system. At the time, the airplane had accumulated 509 total flight hours.
Examination Findings
Post-incident examination revealed that the simultaneous full left aileron and full right rudder inputs caused the rudder-aileron interconnect (RAI) arm to capture the forward RAI bungee clamp, locking both the yaw and roll controls. The airplane was configured in accordance with the existing design, manufacturing, and maintenance guidance and procedures.
Investigation Results
During the investigation, the National Transportation Safety Board (NTSB) was notified of a similar control interference occurrence involving another SR-20, as well as instances of RAI bungee cord slippage through the bungee cord clamps. Such slippage could result in increased roll control input forces or adverse effects on the operation of the aileron trim system. Evidence indicated that the existing design and rigging guidance was insufficient to prevent control interference and clamp slippage.
Corrective Actions
In response, the manufacturer issued a mandatory service bulletin that changed the rigging procedures and RAI hardware. The service bulletin was revised three times as safety information was gathered from airplane examinations and bungee testing. The Federal Aviation Administration also issued an airworthiness directive, making the changes mandatory.