Date: 201604
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Aircraft: B777-200
Operator: Air Carrier
Operating under: Part 121
Mission: Passenger
Flight phase: Parked
Aircraft component: APU Controls
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Pilot Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural MEL / CDL
Detector: Person Flight Crew
When detected: Pre-flight
Result: General Release Refused / Aircraft Not Accepted
Contributing factors: MEL; Aircraft; Human Factors
Primary problem: Human Factors

Narrative: Was scheduled to fly a B777. Flight plan showed a MEL with an open APU door in flight and an extra increase of 10;500 pounds of fuel burn for door drag and windmill/burn. Got to the aircraft and was told the logbook was down stairs as the mechanics were working on an APU oil quantity low light and a low level oil quantity in APU. Was told later that the MEL had been there for 8 days and the APU had to be refilled from very low on every flight for the last 4 days even though it hasn't been run in flight. They said they topped off the APU with oil but they couldn't extinguish the APU low oil EICAS message or the low oil quantity on the diagnostics page. They got it to clear and it came back on again. I asked why the APU was losing so much oil when it has not been running and they deduced it was because it was wind-milling and eating the oil through the seals and bearings etc. I wasn't convinced of that but was more concerned about the indications of low oil qty. After troubleshooting for 3 hours they asked if I was happy to take it with an inoperative oil quantity indicating system and EICAS message showing. The mechanic who was supposed to be the guru came out and indicated there was nothing to worry about even if it was leaking oil because the APU will shut down in flight with low oil pressure or high oil temperature. I quickly realized he didn't know how the APU operates in flight and those are not the items the APU will shut down for in the attended mode which is engines running or in flight. I heard rumblings from an earlier mechanic that the Tech working the flight was not comfortable letting the aircraft go with its' history and the fact we don't have anything to tell us if it's operating with no oil or not. Finally after 3 hours I told the local mechanic that I wanted to talk to the Tech REP working the flight. He called and after discussing the situation; he said he felt uncomfortable letting it go and was told that I was happy to take it with an inoperative oil quantity sensing system for the APU. I told him I wasn't happy about it all since the APU will not shut down for low oil pressure or high oil temp and if over the Pacific it starts spewing smoke or fumes into the cabin from operating with no oil; I was not going to take that risk. He said that was his concern completely and with its' history of coming in from every flight with very low oil; he didn't feel comfortable even though it is probably correct it is due to the wind-milling. He said if it is a leak; then running it now which nobody has done in the last 8 days would put us in unknown territory. I talked with my cockpit crew for feedback from them and they concurred that they didn't feel comfortable and at that point decided I was rejecting the aircraft for safety reasons. We never did see the logbook until it was brought up for me to refuse the aircraft.




Synopsis: The Captain of a B777 refused to accept the aircraft for flight due to an APU door open in flight. Fuel burn would have been excessive and the constant low oil quantity was a concern.