Date: 201309
Local time of day: 0001-0600
Location: ZZZ.Airport, US
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Parked
Aircraft component: Emergency Exit Lighting
Component problem: Failed
Reporter organization: Air Carrier
Reporter function: Pilot Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural MEL / CDL
Detector: Person Flight Crew
When detected: Pre-flight
Result: General Flight Cancelled / Delayed
Contributing factors: Company Policy; MEL; Aircraft
Primary problem: Aircraft

Narrative: I noticed that the Release 2 was issued when I printed the flight plan paperwork. Release 2 stated MEL Added-Over wing Aft Left Slide Light. The deferral was a dispatch item. I printed a copy of the MEL and reviewed it. It was for escape slide lighting for main entry doors and over wing exit slides and it stated that it may be inoperative provided aircraft is restricted to daylight operations. Operations placard also stated flight planning restrictions: Night operations are not authorized. Flight crew note also stated that associated door remains usable.  I was concerned that flight was scheduled to depart at XB:02 am and it was still pitch dark outside. Our FOM instructs that the Captain must resolve any discrepancy between limitations found on the Release and those provided by the Dispatch on the flight plan. So I called the Dispatcher for a conference call with Maintenance Control. I mentioned about the restriction of no night operations and aircraft restriction of daylight operations. I also asked Maintenance Control why this MEL was issued. He said that they could not fix the slide lighting and this lighting is required for operations at night. He also told me that these lights are required for passengers to see the surrounding area of the slide at night.  Dispatcher told me that her Supervisor told her that we were ok to go because they use the night definition of ICAO. It defines the night as the hours between the end of evening civil twilight and the beginning of morning civil twilight. She claimed that we do not use sunrise. I asked her what the actual twilight and sunrise times were. She told me that twilight was XA:50 am and sunrise was XB:23 am.  I told her that we need some daylight for us to be able to use that slide in case of an evacuation. We should not close the door and push until we have some daylight which happens after sunrise not at civil twilight. I can tell that both Maintenance Control and the Dispatcher were under considerable pressure to get an on time departure. Neither one of them wanted to take the blame. Maintenance Control even accused me of splitting hair. Dispatcher told me that she has to inform the Ops Supervisor about this. I told him that it's my decision and I'll take the responsibility. I also told him that I'll call and notify the Duty Manager about my decision. My next call was to Duty Manager. I explained the situation to him. He initially told me that I was flying east so sun will eventually rise and I should be ok to push in dark conditions.  I explained to him that I need that exit to be usable on the ground not after takeoff. He then agreed with me and he promised me to notify a group of people that reviews the MELs; so they can make the MEL card and restrictions clear and easily understandable. We eventually pushed back at sunrise at XA:23am. My First Officer and I agreed that civil twilight did not have enough daylight for that slide area to be visible.  I also received a call from the Chief Pilot Office about this when I arrived at my hotel.  I made the same explanation to the Flight Manager on the phone.  I think that this MEL card should be written with more detail to make it easier for pilots and dispatchers. I think that putting pressure on the dispatchers and maintenance people causing unnecessary stress and distraction. They in turn are trying to pressure the captains. That needs to be stopped. At the end; I ended up taking the delay. Even though this delay was caused by the MEL item restriction due to Maintenance's inability to fix the slide lighting. Company needs to find the actual cause for the delays. Not play the blame game.




Synopsis: Air carrier Captain is issued a release with a deferral for escape slide lighting which the MEL allows for daylight operations only and the flight is scheduled out before sunrise. The Dispatcher states that the company uses civil twilight as daylight in accordance with ICAO definitions. The Captain does not believe this definition of daylight meets the letter of the MEL and departs at sunrise.