NTSB Identification: LAX05LA110.
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Accident occurred Wednesday, March 09, 2005 in Tucson, AZ
Probable Cause Approval Date: 02/28/2006
Aircraft: Cessna A185E, registration: N4530F
Injuries: 5 Uninjured.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

The airplane ground looped during the landing roll. The pilot performed a wheel landing, and as the tailwheel touched down, the airplane began veering to the left. The pilot applied right rudder, followed by the application of the right brake, attempting to stop the leftward veer. The airplane continued to the left and ground looped. The right main landing gear sheared off, proceeded by ground impact of the right wing, right elevator, and right stabilizer. As the pilot exited the airplane, he noted that the winds were calm. Post accident examination of the tailwheel assembly revealed that the tailwheel-locking collar had not been installed on the tailwheel fork assembly. The purpose of the tailwheel-locking assembly is to prevent uncommanded swerve or aircraft direction change during takeoff and landing. It was not apparent that the tailwheel-locking collar had not been installed until the tailwheel was disassembled. The tailwheel locking bell crank was installed on the tailwheel bracket assembly, and is designed to engage with the tailwheel-locking collar to lock the tailwheel. In the cockpit, the tailwheel-locking control and the tailwheel-locking bell crank operated normally. However, the tailwheel could not be locked without the tailwheel-locking collar installed. The steering notch on the tailwheel steering arm assembly that enables the tailwheel to steer the airplane was worn out. The worn tailwheel steering arm assembly allowed the tailwheel to be turned about the steering axis with only light force applied by hand. The worn tailwheel steering arm assembly would allow the tailwheel to swivel without command during a swerve. Review of the airplane's logbooks did not reveal when the tailwheel assembly was last disassembled. The last check on the tail wheel was during the last annual inspection.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

a loss of directional control due to the failure of unknown maintenance personnel to install the tailwheel-locking collar, and the inadequate maintenance inspection of the worn tailwheel steering arm.

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