Q400 flight crew experienced a cargo door warning light at FL240 and elected to divert. Maintenance attempted to defer the door warning system under MEL 52-10-5; but the crew did not believe this MEL fit the problem and refuseed the aircraft.
Synopsis
Q400 flight crew experienced a cargo door warning light at FL240 and elected to divert. Maintenance attempted to defer the door warning system under MEL 52-10-5; but the crew did not believe this MEL fit the problem and refuseed the aircraft.
Narrative
Climbing through 11;000 FT MSL; the Master warning FUSELAGE DOORS warning momentarily illuminated (about 1 second). By the time we could flip the MFD to the ESID DOORS page; the warning was extinguished. We contacted Maintenance Control and Dispatch and informed them of our intention to continue since pressurization had been normal throughout the climb profile thus far and the warning was very transient. We received their blessing to do so and 'pressed on'. Cruising for a bit at FL240; we again received the FUSELAGE DOORS warning. This time it remained continuously illuminated and we were able to diagnose the FWD CARGO DR as indicating unsafe. Following the checklist; we arrived at the statement 'Doors cannot be confirmed secure or pressurization not normal'. Since the handle for the door is on the outside of the aircraft and there are not any door- mounted pin indicators; the checklist does a good job of stating the problem. We complied with the remainder of the checklist including the direction to 'Land Immediately at the nearest suitable airport'. A few minutes later I was able to notify Dispatch of the intent to divert. The door warning extinguished on short final and moments later we landed relatively uneventfully. We coordinated deplaning of the passengers with the station; talked again to dispatch to finalize the change of destination; and discussed the discrepancy further with Maintenance Control who informed me that the mechanic would be on board the next flight; which was a few hours out. I went into the operations area to use the computer while the rest of the crew headed towards the gate area for lunch. As I was finishing up the report in the operations area; I heard some discussion in the background about an imminent departure of our aircraft. I asked what was going on; and the Customer Service Agent said that they had instructed the passenger to re-clear security and that the flight would leave as soon as possible. She also stated that I should contact Maintenance Control regarding the deferral.After thinking 'what deferral?' I did as instructed and the Maintenance Controller advised me of their intention to MEL the door warning system. Through multiple conversations with Maintenance Control and the Duty Officer; I expressed my three reservations about utilizing that MEL; as pilot in command of the aircraft.1. Since the door was indicating closed while sitting static on the ramp and no MEL provision to deactivate a particular door's warning system existed; there was no reason to think that the door warning would not reoccur in flight. With no 'fix' performed to ensure that the affected door remains indicated 'open' at all times; the possibility of spurious 'master warning' lights and triple chimes seems inconsistent with application of the MEL or flight safety.2. The FUSELAGE DOORS MEL involves a 'Maintenance or Pilot' Procedure. Step 1 involves determining the inoperative door sensor by observing the ESID doors page. With the light occurring in flight only; there is no evidence of the fault at the gate. Subsequent steps attempt to confirm correct operation of the door warning system on top of the existing door fault. With the fault only occurring in-flight; the test is not representative of the original condition of the fault.3. The FUSELAGE DOORS MEL compels the crew to consider auto-pressurization inoperative and operate in manual mode. This is a complex; high-workload procedure. For me to consider accepting an aircraft with this MEL; I would have to be in day; VMC conditions without any terrain or weather considerations; at minimum. I consider the distraction of having the pilot not flying to almost continuously observe and adjust the pressurization valves as an unacceptable degradation to flight safety in all but the most basic of flight operations. ZZZ is a mountainous airport with a complex-special engine-inoperative departure procedure and we would have been operating in IMC; icing conditions. My dispatcher informed me that our destination had a convective SIGMET for thunderstorms that would likely require significant attention during arrival.Notwithstanding reasons 1 and 2 above; it was an easy decision to decline to apply the FUSELAGE DOORS MEL to this flight. In between interactions with Maintenance Control and Dispatch; I also had three conversations with the Duty Officer. The content of these conversations are my central safety concerns and thus the reason that I am filling out this report. The first several minutes of my conversation with the Duty Officer; ostensibly about my concerns about the MEL; consisted of the Duty Officer questioning my decision to divert to ZZZ rather than continue to destination. The Duty Officer; while having the applicable Q400 checklist at his disposal; questioned my interpretation of the checklist decision tree that resulted in the diversion; and seemed to mock the decision by derisively stating that maybe 'checklist meanings are different in the Q400'. During our first conversations; he attempted to persuade and intimidate me to take the airplane with passengers under the FUSELAGE DOORS MEL. He asked me 'how the passengers would feel about this?' and tried to guilt me into taking our tough-luck passengers to destination despite my concerns about the safety of the operation. He told me a story about a crew that invented an ad-hoc procedure to fly unpressurized between two airports because of the workload associated with the manual pressurization requirement of the MEL. Finally; he asked me to consider taking the airplane because it will be difficult to justify my refusal of an 'airworthy' airplane to a Chief Pilot... basically; as I perceived it; a disciplinary threat. It was at that point that I realized that we were probably talking 'off the record' because he was obviously acting in a manner inconsistent with someone that has operational control of the airline. I asked him if we were on a recorded telephone line. He stated uncomfortably that we were not. I told him that I felt like he was attempting to threaten and harass me; the PIC; into taking an aircraft that did not meet my requirements for the proposed mission and that any further discussion would have to be on a recorded phone line. Shortly after this statement; we ended the conversation and the departure time was pushed back until maintenance arrived. Maintenance exercised the door several times and expressed intent to MEL the doors under the same provision as earlier. It was only after I restated my concerns operating under the MEL that the mechanic was directed to interrogate the MDC; and a fault in the door handle alignment sensor was found registered. We ferried the aircraft the following morning for repair after the mechanic identified that the trigger for the FUSELAGE DOORS warning was solely a slow closure of the FWD CARGO DR. It seems that the FUSELAGE DOORS warning MEL is not being correctly applied by maintenance control. It should only be used when the applicable door will ONLY indicate unsafe when it is verified closed; not when it is showing closed and safe on the ground after indicating unsafe in the air.
Second reporter narrative
On climb through 11;000 got a MASTER WARNING and FUSELAGE DOORS Warning light. Called checklist; by the time we pulled it out and switched MFD to DOORS page the FUSELAGE DOORS Warning light had extinguished. Called Dispatch; was patched to Maintenance Control. After consulting maintenance with no further indications of insecure doors we continued. In cruise flight we got a MASTER WARNING and FUSELAGE DOORS Warning light. Called the checklist; and determined the FWD BAG Door was showing red on the MFD DOORS page. The FUSELAGE DOOR Warning light was steady this time and the FWD BAG Door red indication remained steady. The checklist ultimately leads us to the decision to LAND IMMEDIATELY AT THE NEAREST SUITABLE AIRPORT due to the fact the 'Doors cannot be confirmed secure.' A diversion was implemented. Dispatch; Maintenance was informed as well as the flight attendants and passengers. On short final below 1;000 FT I noticed the FUSELAGE DOORS Warning light extinguished. Once passengers were deplaned; I went to the terminal to get some food; while the Captain went to Operations. A while later I meet the Captain; whom wanted to have a discussion with me. From this discussion with the Captain I understood that Maintenance wanted to MEL the FUSELAGE DOORS WARNING LIGHT System under MEL 52-10-5. I also learned the Captain had refused to accept the aircraft with this MEL. Upon reading the MEL myself I did not feel the MEL would be applicable to our situation. The MEL states that 'a. The fault is verified to be a proximity sensor by an acceptable procedure.' The Maintenance or Pilot Procedure states '3. With FUSELAGE DOORS Warning light steadily illuminated...' On short final the FWD BAG door red light had extinguished; and with the door appearing closed on the ground; the MFD door page confirmed this. The other issue I had was since this warning had been intermittent; there was a significant chance of getting a MASTER WARNING at any time during subsequent flights. It seems like a poor decision to takeoff with an aircraft that could give random MASTER WARNING lights during any phase of flight especially the Takeoff roll as this would require a Takeoff Abort. The Captain also advised me that the Duty Officer had questioned his decision to divert as per the Checklist and had suggested that we read the checklist wrong and should not have diverted. After subsequently reading the FUSELAGE DOORS WARNING checklist on the ground it seems apparent that to not divert would have been a deliberate disregard of the Checklist. The Captain also stated that the Duty Officer also questioned the Captains authority to refuse the MEL for the aircraft. Later that evening Maintenance arrived to the aircraft and determined a fault code associated with the door handle latching mechanism existed and that the aircraft would need a ferry permit.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.