Narrative:

I am filling this report for reasons of flight safety and regulatory compliance. I was notified by the safety committee to give detail regarding the flight. During preflight planning; assigned a boeing 767. Aircraft had an existing deferral 52-71-X-X door indication systems-main deck cargo. Noted that part of the MEL procedure was that the associated door(s) be verified closed; latched; and locked before each departure. Under operational limitations; none. Preflight and loading completed; met face-to-face with two mechanics who complied with the deferral/MEL procedures; made the entry in the logbook; and left. Block-out; taxi; and takeoff were uneventful. In cruise; FL340; EICAS message: 'main cargo door'; master caution illuminated; and several warning chirps sounded. As the pilot flying; I asked the first officer to consult the quick reference handbook (QRH); which; in fact; he was already doing. Procedure called for depressurizing and descending to 10;000 MSL or lowest safe altitude. Initially I was surprised; expected the procedure to say if pressurization remained normal; monitor but continue. Further down the checklist it says just that for a bulk cargo door message. Convinced our actions were correct; made the request with ATC and began descending and depressurizing. While descending; passing approximately 2 psi cabin differential; all warnings disappeared. At my instruction; first officer contacted operations and maintenance. They had no further advice concerning the abnormal flight condition. When asked where they wanted the airplane; we were advised it was up to the crew. ZZZ seemed the best alternative to me; so we advised the dispatcher we would be returning. He sent an amended release changing our destination to ZZZ. Landing and block-in were uneventful. Contacted dispatcher to see what the next step was; advised they intended to refuel and relaunch. I stated that maintenance needed to look at the aircraft and if not; I would not operate the flight. At some point an operations chief pilot entered the cockpit and discussed the events which had just transpired. He stated that due to the deferral; the door warning system was considered inoperative; any warnings should be ignored and I should not have consulted the QRH. In fact; another management captain on a previous flight had done so. I disagreed. The MEL for this circumstance makes no mention of ignoring warnings. In other mels; procedures physically disable/deactivate systems in order that false warnings not occur. There are also mels that make mention of warnings in flight that can and should be ignored as a part of a deferral procedure. The chief pilot asked what I would do if the warning occurred again; I stated I would again follow the QRH. He asked if I would accept the aircraft in its current condition and I said no. He said he had a replacement captain present and I was to leave the aircraft; file an event report; and contact crew scheduling. Operations supervisor transported me back to operations where I filed my report. I called crew scheduling who said I needed to talk to [the chief pilot]. I asked him what I should do. Stay? Go home? He stated I should go home. If I didn't hear anything further; I should show up [in two days] to pick up my trip sequence. Though I haven't yet spoken to anyone at [company]; [the union] has advised me I have been 'withdrawn from service' because of circumstances related to the flight described herein.

Google
 

Original NASA ASRS Text

Title: B767-300 flight crew reported receiving a MAIN CARGO DOOR EICAS message that was an MEL item and elected to return to the departure airport. The Chief Pilot suggested that they should have continued the flight and disregarded the door warning.

Narrative: I am filling this report for reasons of flight safety and regulatory compliance. I was notified by the Safety Committee to give detail regarding the flight. During preflight planning; assigned a Boeing 767. Aircraft had an existing deferral 52-71-X-X DOOR INDICATION SYSTEMS-MAIN DECK CARGO. Noted that part of the MEL procedure was that the associated door(s) be verified closed; latched; and locked before each departure. Under OPERATIONAL LIMITATIONS; NONE. Preflight and loading completed; met face-to-face with two mechanics who complied with the deferral/MEL procedures; made the entry in the logbook; and left. Block-out; taxi; and takeoff were uneventful. In cruise; FL340; EICAS message: 'MAIN CARGO DOOR'; master caution illuminated; and several warning chirps sounded. As the Pilot Flying; I asked the first officer to consult the Quick Reference Handbook (QRH); which; in fact; he was already doing. Procedure called for depressurizing and descending to 10;000 MSL or lowest safe altitude. Initially I was surprised; expected the procedure to say if pressurization remained normal; monitor but continue. Further down the checklist it says just that for a BULK CARGO DOOR message. Convinced our actions were correct; made the request with ATC and began descending and depressurizing. While descending; passing approximately 2 PSI cabin differential; all warnings disappeared. At my instruction; first officer contacted Operations and Maintenance. They had no further advice concerning the abnormal flight condition. When asked where they wanted the airplane; we were advised it was up to the crew. ZZZ seemed the best alternative to me; so we advised the dispatcher we would be returning. He sent an amended release changing our destination to ZZZ. Landing and block-in were uneventful. Contacted dispatcher to see what the next step was; advised they intended to refuel and relaunch. I stated that maintenance needed to look at the aircraft and if not; I would not operate the flight. At some point an Operations Chief Pilot entered the cockpit and discussed the events which had just transpired. He stated that due to the deferral; the door warning system was considered inoperative; any warnings should be ignored and I should not have consulted the QRH. In fact; another management captain on a previous flight had done so. I disagreed. The MEL for this circumstance makes no mention of ignoring warnings. In other MELs; procedures physically disable/deactivate systems in order that false warnings not occur. There are also MELs that make mention of warnings in flight that can and should be ignored as a part of a deferral procedure. The Chief Pilot asked what I would do if the warning occurred again; I stated I would again follow the QRH. He asked if I would accept the aircraft in its current condition and I said no. He said he had a replacement captain present and I was to leave the aircraft; file an event report; and contact crew scheduling. Operations Supervisor transported me back to Operations where I filed my Report. I called Crew Scheduling who said I needed to talk to [the Chief Pilot]. I asked him what I should do. Stay? Go home? He stated I should go home. If I didn't hear anything further; I should show up [in two days] to pick up my trip sequence. Though I haven't yet spoken to anyone at [company]; [the union] has advised me I have been 'Withdrawn From Service' because of circumstances related to the flight described herein.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.