A320, Gold Coast QLD Australia, 2017
From SKYbrary Wiki
|On 18 December 2017, an A320 crew found that only one thrust reverser deployed when the reversers were selected shortly after touchdown but were able to retain directional control. The Investigation found that the aircraft had been released to service in Adelaide with the affected engine reverser lockout pin in place. This error was found to have occurred in a context of multiple failures to follow required procedures during the line maintenance intervention involved for which no mitigating factors of any significance could be identified. A corrective action after a previous similar event at the same maintenance facility was also found not to have been fully implemented.|
|Actual or Potential
|Airworthiness, Human Factors, Runway Excursion|
|Type of Flight||Public Transport (Passenger)|
|Origin||Adelaide International Airport|
|Intended Destination||Coolangatta/Gold Coast Airport|
|Take off Commenced||Yes|
|Location - Airport|
|Airport||Coolangatta/Gold Coast Airport|
|Tag(s)||Procedural non compliance|
|System(s)||Engine - General|
|Contributor(s)||Maintenance Error (valid guidance available)|
|Damage or injury||No|
|Causal Factor Group(s)|
On 18 December 2017, an AIRBUS A-320 crew (VH-VQG) being operated by Jetstar Airways on a scheduled domestic passenger flight from Adelaide to Gold Coast had just touched down normally at its destination in day VMC when thrust reverser selection by the Captain was followed by deployment of only the right engine reverser with an indication of a ‘reverse fault’ on the left engine reverser appearing. The reverser controls were moved to the stowed position, directional control was maintained and taxi in completed.
An Investigation was carried out by the Australian Transport Safety Bureau (ATSB) after it was found on a post flight engineering inspection that the left engine reverser had not deployed when selected because its lockout pin was fitted.
It was established that the flight involved was the first of the day after completion by contracted MRO Qantas of overnight maintenance on the left engine which had been carried out by two licensed aircraft maintenance engineers whilst the aircraft was parked outside.
Unscheduled work on the aircraft to investigate an engine bleed air issue reported by the aircraft operator but with no supporting paperwork provided had commenced at about 2300 local time. One of the engineers “began collecting the consumables required for the task” whilst the other went to the ramp stores unit to get a thrust reverser lockout pin which had to be installed to prevent inadvertent activation of the reverser during the task. He did not book out the pin on the stores computer system, which was a required action. On reaching the aircraft, he opened the left engine cowling and with the use of a stand to reach the top of the engine, installed the pin. He did not then record this action, as required by procedures, in the Aircraft Technical Log which he was aware was in the line office, instead deciding to do this “later”.
The investigation of the bleed air issue was completed over the next couple of hours, by which time it had begun to rain. The engineer who had inserted the lockout pin then “made a visual inspection around the engine” prior to closing the cowling. By this time ramp floodlighting had reduced because half the lights automatically turned off at midnight and the engineer “missed seeing the lockout pin and its 1 metre-long red warning flag and closed the cowling".
With the task completed, both engineers went to the line office to complete the necessary paperwork. Each recorded different parts of the completed maintenance, but neither of them entered the installation and removal of the lockout pin in the Technical Log. Prior to the release of the aircraft to service, a tooling inventory check was required and made but as the lockout pin had not been booked out on the stores computer system, “it did not show up during the check” and release to service was made with the lockout pin installed.
It was found that the flag on the pin used was shorter than those on similar pins in the (main) hangar tool store at Adelaide, “which had been lengthened to 4 metres after a previous incident to make them more obvious”. It was also observed that it was known that the red colour of the flag would have been harder to see under artificial lighting and noted that it was “not fitted with reflective material” and noted that the stand which the engineer had required to be able to install the pin “and which may have reminded him about it” had been removed.
It was also found that the AMM procedure for thrust reverser de-activation also explicitly required that specific warning labels should be placed in the flight deck reading “thrust reverser HCU is de-activated” (the HCU is the hydraulic control unit) which was not done during this work.
It was noted that the previous event of this sort at Adelaide, which had not been subject to an independent external investigation, had occurred in January 2017 also to a Jetstar A320 which, after failure to remove a lockout pin with a 1 metre flag, had been released to service for a flight to Melbourne where the corresponding reverser did not deploy when selected. It was this event that had prompted the decision to replace lockout pin 1 metre flags at Adelaide with 4 metre ones.
It was also noted that nine months after the event under investigation, a similar event involving the non-removal of lockout pins on both engines of a Jetstar A320 prior to release to service at Brisbane had resulted in the reversers not being available after landing at Sydney Airport. In this case, the ATSB Investigation found that the reversers were disabled for maintenance purposes using in-service pins without flags instead of the required aircraft maintenance lockout pins which have warning flags and also the required functional check of the reversers following reactivation “as per the operator’s task card for that planned maintenance” was not carried out.
Safety Action taken as a result of the investigated occurrence and reported to the Investigation whilst it was in progress was recorded as having included the following:
- Qantas has lengthened all thrust reverser lockout pin flags so that they now hang past the closed cowls and attached a warning notice to each pin flag which must be placed on the flight deck engine thrust reverser controls during maintenance.
- Airbus has revised the AMM to add a requirement for an operational test of the thrust reverser system to confirm its re-activation after maintenance tasks.
The Final Report was released on 5 September 2019. No Safety Recommendations were made.