B737-400
Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Communication Breakdown
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural MEL / CDL; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy
General Flight Cancelled / Delayed; General Maintenance Action
Aircraft; Company Policy; Procedure; MEL; Logbook Entry
Pilot in Command conducted four flights in Aircraft X. There was an Non-essential Equipment Furnishing in the aircraft maintenance logbook listed as 25-XXXX; Forward Lav flight attendant call button inopperative; dated [date]. However; as I discovered after the flights were completed; this MEL was not the correct one for the aircraft condition. I was again assigned to Aircraft X in ZZZ and I was conducting my preflight inspection. I was reviewing MELs and maintenance records and it suddenly struck me that the attendant call button might not be possible to defer. I reviewed the Minimum Equipment List and noted that MEL 25-XXX applied to 'Cabin reading lights; light lens covers; and lav occupied lights may be inoperative provided enough light is available for safe working conditions during night operation.' Consequently the MEL did not apply to the flight attendant call button in the forward lav. A review of the records indicated that Aircraft X had conducted numerous flights since the MEL 25-XXXX had been applied to the aircraft.I checked the expiration date of the Non-essential Equipment Furnishing; noted that it was still within limits before expiration; and I didn't investigate farther. Consequently I conducted the flights listed above.I contacted local maintenance personnel and Maintenance Control and informed them of the situation; stating that I would not be able to fly the airplane until the issue was corrected and I could legally fly the airplane. Subsequently; the forward lav was locked out and deferred in accordance with MEL XX-XX; paperwork was completed and I subsequently conducted all the following scheduled flights for the day; although the flight was delayed due to the maintenance issue. This has been a recurring issue with incorrect MEL/NEF guidance from Maintenance Control which result in aircraft flying when they are legally required to be repaired; grounded; or a more a more restrictive action is due to be applied.
B737 Captain reported that an aircraft flew several times with an incorrectly applied MEL.