Incident Overview
During landing at Karratha Airport, the right engine thrust reverser on aircraft VH-NHA did not activate. The malfunction occurred because the in-service lockout bolt for the thrust reverser mechanism was still installed.
Maintenance Error
Before the flight, a maintenance engineer in Perth had installed the lockout bolt to safely isolate the thrust reverser during a maintenance task. Instead of using the specified maintenance lockout bolt, the engineer used a bolt from the cockpit because it was conveniently located. After completing the work, the engineer mistakenly did not remove the bolt.
Missed Detection
The presence of the bolt was not identified for several reasons. The usual risk controls associated with the specified lockout bolt were rendered ineffective because the wrong bolt was used. Specifically, there was no warning flag attached to the bolt to alert the engineer, dispatch engineer, or flight crew that the bolt was still installed. Additionally, the tooling check that would have identified the bolt had not been removed was circumvented. Furthermore, the cockpit lacked warning labels to inform the flight crew that the bolt might be installed.
Return to Service
As a result of these oversights, the aircraft was returned to service with the thrust reverser deactivated. This condition was not identified prior to the flight, leading to the inoperative thrust reverser upon landing.