Incident Overview
An aircraft experienced a reduction in turning ability while attempting a turn on the runway, resulting in an excursion onto the runway strip. The incident did not result in any aircraft damage.
Maintenance Findings
Examination revealed a torn boot on the universal joint. According to the captain's statement, it is likely that the torn boot reduced the universal joint's range of motion, which in turn restricted the operation of the nose-wheel steering. This restriction diminished the aircraft's turning capability, preventing it from completing the turn on the runway. The cause of the boot tear could not be determined.
Runway Strip Considerations
Runway strips are designed to minimize the risk of damage, but there is no guarantee that an aircraft can safely maneuver on them. Although the excursion onto the runway strip did not result in aircraft damage, there was no assurance that the strip was free of hazardous debris. However, if the aircraft had remained on the runway, other aircraft would not have been able to land safely, and ground support equipment delivery to maneuver the aircraft along the runway would have been hindered. Options such as having airport staff inspect the runway strip before turning were available.