A Jetstar Airbus A320 was unable to deploy its thrust reversers during a landing at Sydney on 20 September 2018, after engineers forgot to remove a maintenance pin during an earlier maintenance task.

As the aircraft, registered VH-VGZ, was completing its roll out after landing on a flight from Brisbane, the crew attempted to activate reverse thrust and received a “reverse fault” indication. They were able to complete the rollout using normal braking and there were no injuries nor damage to the aircraft.

The Australian Transport Safety Bureau’s (ATSB) final report into the incident found that the captain did not observe any indications on the engine cowling nor in the logbook that the thrust reverser system was inoperative.

An engineering inspection discovered that the reversers had been de-activated with a minimum equipment list pin installed in each engine. After they were removed, the reversers were found to be serviceable and the aircraft re-entered service.

The ATSB report notes the A320 underwent a three-day maintenance check at the Qantas facility in Brisbane that started on 17 September. During that check, engineers identified that the horizontal stabiliser actuator required replacing, which would add half a day to their workload.

That required an additional team to complete the task, early on 20 September and a licensed aircraft maintenance engineer signed off on a task card that required a functional check of the thrust reverser system on the morning of 20 September.

“Based on the system test of the thrust reversers, but contrary to the required procedure, he also completed the certification for the same check on the ‘hangar release’ task card,” states the ATSB.

The crew then turned their attention to completing other tasks, and around a similar time, Jetstar requested that the aircraft re-enter service four hours earlier than planned. That put pressure on the engineers to complete all required tasks and tests, and some reported feeling fatigued. Qantas adds however that all of the engineers involved had been fit for work under its fatigue management systems.

One of the tests was an engine leak check, which required the use of a lockout pin with a red flag to de-activate the thrust reverser system, with notices placed in the cockpit. Instead, an MEL pin without a flag was used to complete the test due to the time pressure, as it would have taken longer to get the proper-flagged pin.

“The installed MEL lockout pins were not identified following completion of the engine leak check procedure. Consequently, both engine cowlings were closed with the lockout pins in place and the thrust reversers inoperative,” says the ATSB.

It adds that a “deviation from the required maintenance procedures” resulted in it being released for service with the thrust reverser system inadvertently inoperative, while the time pressure may have influenced the engineers to deviate from the procedure.

Following the incident, Qantas raised it with its engineers for further discussion, and created an A320 de-activation board with the correct lockout tooling that sits on a trolley next to the aircraft during a service to make it easier to access.

“This incident serves as a reminder that a failure to follow procedures, such as functional checks, can result in unintended consequences,” says the ATSB. “Functional checks are the last line of defence in maintenance work and can identify a range or errors that may have occurred during the job completion process. The extra few minutes taken to complete a functional check could detect an unsafe situation.”

Source: Cirium Dashboard