Maintenance Powerplant; Maintenance Airframe
Workload; Communication Breakdown; Confusion; Time Pressure
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural MEL / CDL; Deviation / Discrepancy - Procedural Published Material / Policy
General Maintenance Action
MEL; Procedure; Incorrect / Not Installed / Unavailable Part; Aircraft; Human Factors
I; Maintenance Controller; placed an MEL on an A321 aircraft that was in ZZZ1; but our computer systems were down and could not access the full MEL menu due to an outage from our communications provider and was not aware the Flight Warning Computer (FWC-1) could not be MELed.  I did not have our Air Carrier's full MEL procedure to use. [Recommend] having a better back up [procedure] for computer failures.
At the Gate; first flight of the day; received Flight Warning Computer-1 (FWC-1) ECAM FAULT. Attempted unsuccessful QRH reset procedure. Called Maintenance Control and attempted several other unsuccessful reset attempts with Maintenance Control. Crew was then instructed by Maintenance Control to apply MEL 31-XX-XX. Followed verbatim the Maintenance controller's instructions in applying the MEL. The MEL stated that FWC-2 could be MEL'd with the application of MEL XX-XX-XX; downgrading the aircraft's CAT-IIB capability. The MEL did not specifically say that FWC-1 could not be MEL'd (although it is implied with the statement that FWC-2 could be MEL'd) and Maintenance Control said nothing about switching FWC-1 with FWC-2. After applying the MEL; the flight proceeded ZZZ1 to ZZZ2 without incident. Upon arriving in ZZZ2; during the walk around; I noticed a Contract Mechanic in the E/E Bay; when I asked him what he was doing (I was never contacted or notified by Maintenance Control that this was going to happen) he told me he was switching FWC-1 with FWC-2. I then called Maintenance Control and asked them if we misapplied the MEL; he told me they should have switched the FWC boxes in ZZZ1 prior to our departure and that FWC-1 can't be MEL'd.In this case I questioned whether we could MEL FWC-1; but did not question the Maintenance Controller's instructions during the application of the MEL. In my opinion the MEL is not completely clear regarding whether or not FWC-1 can be MEL'd. I think there should be a sentence that specifically says FWC-1 cannot be deferred and there should be a Maintenance procedure that specifies the FWC boxes need to be switched before flight. Maintenance personnel need to be better trained and I needed to be more diligent in reading/applying the MEL. In addition the crew was dealing with a lengthy delay due to the computer system being down; we were dealing with multiple issues in addition to the maintenance problem.
A Maintenance Controller and Captain report on events that contributed to an improper deferral of #1 Flight Warning Computer (FWC-1) ECAM FAULT and dispatch of an A321 aircraft. Pilot notes there should be a sentence in the MEL that specifically says FWC-1 cannot be deferred; and a Maintenance Procedure that specifies the FWC boxes need to be switched before flight; which had not been accomplished.