Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Other / Unknown
General None Reported / Taken
Company Policy; Aircraft; Equipment / Tooling
Dispatched with APU INOP for a transoceanic flight. WHY? ..the Aircraft X is a very hungry electrical power aircraft and the APU is a very critical component to supply Emergency and Normal Electrical Power. Even though the MEL allows this placard the 'Safety Implications' alone should override flying this aircraft over water on several 9-11 hour flights. This APU had been on placard for four days and allowed to fly through major Maintenance Hubs without repair. Why?  While I believe the 'Spirit' of the MEL is to allow the aircraft to continue for a short duration or even Domestic Operations where 'Emergency' airports are plentiful; allowing continued Oceanic flights just to 'keep the operation going' strains the definition Flight Safety. An added threat and danger is the need to be assured that 'Acceptable External Ground' power is available at the gate for the Aircraft X. This is what did not happen as we arrived at our gate; the aircraft accepted the power then when engines were shut down; External Power was dropped by the Gate system and unable to restart the power leaving the aircraft on Battery power.  After five minutes; and calls to Operations; it was apparent that no External Power would be available. So to keep the aircraft battery from to discharging to a dangerous low level; even while passengers were still disembarking I shut all battery electrical power down per checklist. Aircraft X only has 10 minutes of certified electrical power available when all emergency buses are charged and very expensive to replace. A maintenance log book write up was made detailing the time the battery had been powering the aircraft without charge.
Air carrier Captain is dispatched on a transpacific flight with the APU deferred; which it had been for four days. Upon arrival at the gate; ground power is connected and the engines are shut down. Ground power quickly fails and cannot be reestablished leaving the aircraft on battery power alone. After five minutes the battery is turned off leaving the aircraft in darkness.