27th of December 2017

A Network Aviation Fokker F100 (VH-NHA) was operating a scheduled passenger flight from Perth to Karratha Airport, Australia. Onboard,64 passengers, 3 cabin crew and 3 flight crew.

Fokker 100, VH-NHA in June 2017 ©Brenden

The flight had been uneventful and a normal descent and approach to Karratha Airport was flown. At approximately 10.39 lt, ATC cleared the aircraft to land. A normal final approach and touchdown followed and a normal touchdown was made. The Pilot Flying (Captain) selected reverse thrust on both engines as per company procedures. The left thrust reverser deployed, however, the right thrust reverser did not deploy. This resulted in a warning message and aural warning in the flight deck. The aircraft slowed down using the left thrust reverser and normal braking. The left thrust reverser was stowed normally and the aircraft taxied to the aircraft parking position without further trouble. Once the passengers had disembarked the flight crew reported the issue to the maintenance staff at Karratha.

When the maintenance staff carried out the required trouble shooting they found that the reverser lockout bolt was installed in the right reverser. This bolt is part of the aircraft MEL (Minimum Equipment List) kit eand is use for dispatching the aircraft with an inoperative reverser. The bolt mechanically locks the reverser so it cannot be opened by any means. As there was no record of the bolt being installed for any reason in the aircraft technical log, the lockout bolt was removed, and during the subsequent test the reverser operated normally and the aircraft was returned to service.

The lockout botl without the "REMOVE BEFORE FLIGHT" flag installed. ©

An investigation in to the incident found that during maintenance on the previous day work was scarrie dout on the engine. As per Aircraft Maintenance Manual procedure the reverser had to be locked for safety reasons, using a lock out bolt with a "REMOVE BEFORE FLIGHT" flag on it. The engineer decided to ues the lockout bolt from the aircraft MEL to safety the reverser. The MEL kit lockout bolt is physically the same as the pin prescribed by the Aircraft Maintenance Manual, with the exception of the "REMOVE BEFORE FLIGHT" flag. Without the flag it is not impossible to see if the lockout bolt is installed, however being installed 3.5 meters from groundlevel it is easy to mis. After completion of maintenance the tooling stores was checked if all tooling used for maintenance were returned, before the aircraft was released from maintenance. This checked out as the pin used was not from the tool store. The maintenance organisation took measures to prevent reoccurrence. The maintenance lockout bolt with flag

An investigation was carried out by the (source Australian Transport Safety Board in to the aoccurrencend and upon completion issued a report which can be found by clicking here.

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