A320
Maintenance Powerplant; Maintenance Airframe
Confusion
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural MEL / CDL; Deviation / Discrepancy - Procedural Published Material / Policy
General Flight Cancelled / Delayed; General Maintenance Action
Chart Or Publication; MEL; Aircraft; Manuals
Aircraft X had landed in ZZZ we had an inbound write up for ENG #1 abnormal bleed IP valve would not open. I had called Maintenance Control; told them the write up and they directed me to apply MEL 36-XX-XXX and MEL 36-XX-XXX. During the application of this MEL the flight crew was going with they're procedures for this MEL and had no issue with it. Note: HP bleed valve for same engine was already on MEL 36-XX-XXX; nowhere in the maintenance procedures for any of these MELs does it indicate that you can't have all of them applied. Flight crew took Aircraft X from ZZZ to ZZZ1 the next day I was notified by my supervisor that the wrong MEL had been applied. Mel 36-XX-XXX is the MEL that should have been applied not MEL 36-XX-XXX. This was discovered by the flight crew that was taking Aircraft X out of ZZZ1 and they had a conflict with the operation procedures. The maintenance procedures for the bleed system when multiple things are failing are not clear. There's nothing in the maintenance procedures to keep you from applying MELs that counter act each other.The maintenance procedures for the bleed system when multiple things are failing are not clear. There's nothing in the maintenance procedures to keep you from applying MELs that counter act each other.
Technician reported MEL procedures were unclear and allowed technician to defer multiple bleed valves on the same engine; causing a delay.