Widebody; Low Wing; 2 Turbojet Eng
Flight Crew Last 90 Days 100; Flight Crew Total 13400; Flight Crew Type 4400
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural MEL / CDL; Deviation / Discrepancy - Procedural Published Material / Policy
General None Reported / Taken
Aircraft; Procedure
During my preflight; number two battery voltage was zero. After wiggling the rotary selector switch; I found it to be faulty in the number two position. Battery volts would read zero or 25 depending on moving the rotary selector switch. The Captain wrote the switch up in the logbook. The mechanic troubleshoots and determines the switch is defective. He leaves the aircraft and returns to tell us that the switch is not deferrable and the part is enroute. We are told sometime later by maintenance that the part in not enroute and the switch is in fact deferrable [using] MEL for a battery volts indicator and says Maintenance Control wants to sign off using this MEL. The Line Mechanic seems skeptical that this correctly addresses the problem. The Captain and I agree that it doesn't seem correct to us either. The MEL seems to address the voltage indicator and not the rotary selector switch. Later; Maintenance Supervisor presents us with the same MEL. The Captain and I still have the same concerns. The Captain had several conversations with ACPs (Assistant Chief Pilot) and maintenance personnel. Everyone agreed that the MEL was in a gray area. Maintenance signs off the aircraft using MEL. The Captain and I still were not comfortable with it. The Captain spoke with ACP once again and he suggested if we still were not comfortable with the sign off; write the switch up again being even more specific. Maintenance again signed off the write up.  Maintenance Control assured the captain this was a legal deferral and the ACP assured him that he had done everything he could do and that the aircraft was legally deferred. An AWR (Air Worthiness Release) was in the logbook and was signed.
Widebody transport aircraft First Officer disagreed with the applicability of an MEL maintenance used to defer the battery voltage selector switch.