Large Transport
Confusion; Communication Breakdown
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural MEL / CDL; Deviation / Discrepancy - Procedural Published Material / Policy
General Maintenance Action
Chart Or Publication; MEL
Maintenance issued Engineering Request (ER) requesting approval to remove a Brake hydraulic line; cap it; disable the Brake and dispatch using MEL 32-ZZ-ZZ-B. This request was based on the hydraulic line being damaged and leaking hydraulic fluid. Maintenance provided the hydraulic line part number and pictures; but the pictures were not viewable.I reviewed the request by first looking at the MEL's that could apply to the condition.  [The aircraft] MEL 32-ZZ-ZZ-A - Wheel Brakes; was the MEL that should have been used because it deactivated the brake by installing a brake disconnect tool in the anti-skid shuttle valve module which blocks off all hydraulic fluid to the brake. Soon after the ER was submitted; maintenance called me and we discussed the use of MEL 32-ZZ-ZZ-A; and I identified where the brake disconnect tool should be located in the Aircraft. They informed me that they could not locate the brake disconnect tool; and that the Aircraft may not be able to dispatch with a brake disabled by MEL 32-ZZ-ZZ-B because of the runway conditions at the station - this MEL has a Caution statement that does not allow for takeoff on contaminated runways with an inoperative brake.  Because of this limitation; maintenance thought they had to repair the brake line before the aircraft dispatched; so I updated the ER with my findings and awaited to see if they would call back. About an hour later; maintenance called again and requested an [approval] to disconnect the brake line and cap it above the damaged area and they would use MEL 32-ZZ-ZZ-B. Because I had already drafted the [approval]; I was able to issue it approximately 5 minutes later.I vaguely recall discussing with maintenance where the brake line was to be disconnected and I am sure it was to be above the brake line damage; most likely at the end of the damaged line which should have been at or near the connection to the anti-skid shuttle valve manifold; based on our discussions and review of the MEL's. Consequently; and because we had reviewed MEL 32-ZZ-ZZ-A; I wanted the brake line disconnected and capped at the anti-skid shuttle valve manifold; but in the [approval] I identified it to be disconnected and capped at the anti-skid manifold. From a functional standpoint; and from our discussions I am sure maintenance understood that they could disconnect and cap the brake line at any point above where it was damaged and downstream of the anti-skid shuttle valve manifold and it would have been acceptable; since its purpose is to isolate the damage from the pressurized hydraulic brake system. MEL 32-ZZ-ZZ-B accomplishes the same damage isolation procedure except it presumes the leak is at the brake and isolates it by disconnecting the brake line at the brake quick disconnect fitting. I do not know exactly where maintenance actually disconnected and capped the brake line.The brake line part number identified in the [approval] came directly from maintenance's ER input. With the [approval] Authoring System; when we issue an [approval] based on an ER; the part number listed in the ER is carried over into the [approval]. The ER never mentioned the brake line Illustrated Parts Catalogue (IPC) and I did not refer to the IPC before issuing the [approval].It is my normal procedure in the Terminating Action Part to instruct maintenance to repair or replace an item in accordance with the Aircraft Maintenance Manual (AMM) and; in most cases; address the changes made in [approval] Part 1 that need to be un-done. I do not know why in this case I did not mention the changes made in Part 1 except; perhaps; that I felt that it should have been obvious to the AMT replacing the line because it was disconnected; capped and stowed. Nevertheless; I know that all repairs are supposed to be accomplished per the AMM or other approved manuals; but my reasoning for stating this in the [approval] is because the AMM's provide an operational check anytime an item is replaced. By requiring the replacement to be accomplished by the AMM ensures that an operational check will be performed.  Consequently; even if minor system configuration changes are made in Part 1; if the AMT accomplishes the replacement task per the AMM; it should ensure that the applicable system is returned to its normal operating configuration; as evidenced by a successful operational check. The sign-off for replacement of the brake line was AMM 32-ZZ-ZZ that has the following operational check in the Installation procedure section.Make sure that the brakes operate properly as follows:(a) Push in and release the brake pedals while you watch the brake wear indicator pin for movement.(b) Make sure that the brake wear indicator pin extends and retracts when you push in and release the brake.In [fourth quarter] 2015; I learned from a call from a Safety Advisor; that the AMT who accomplished Part 2 of [the approval] had only received Part 2; and not Part 1 that identified that the brake line was disconnected; capped and stowed. Until then it was my understanding that the AMT saw all Parts; but with this new information; I decided to notify my co-worker System and Avionic Service Engineers of the need to ensure that AMTs are made aware of changes in Part 1 that need to be returned to their normal configuration in the Terminating Action Part of the [approval]. So I sent them an Email that addressed this issue. I suggest that we ensure AMTs review; and have easy access to; all Parts of the [approval] they are working on. Ensure Engineers add either general or specific comments in the Terminating Action Part that informs the AMT of the changes performed in previous Parts that need to be addressed. Ensure that all maintenance Stations have the capability to provide visual data into the ER System.
[Report narrative contained no additional information.]
Maintenance requested approval from Engineering to remove and cap a damaged hydraulic line and deactivate the associated brake. A written approval was issued but there was some confusion as to where to disconnect and cap the line and also as to which MEL reference should be used. Maintenance only received part two of the approval and did not receive part one; which led to the confusion. The brake was deferred properly and measures were taken to ensure this doesn't happen in the future.