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Woah, the photos of the charred battery are fairly dramatic: http://www.ntsb.gov/investigations/2013/boeing_787/boeing_787.html http://www.ntsb.gov/investigati
by ljoshua 14y ago
Woah, the photos of the charred battery are fairly dramatic:
http://www.ntsb.gov/investigations/2013/boeing_787/boeing_787.html http://www.ntsb.gov/investigations/2013/boeing_787/boeing_78...
- jlgreco 14y agoMuch smaller than I would have expected. That thing can start an engine that large?
- datasage 14y agoAs I understood it, these batteries power auxiliary systems.
- tfe 14y agoThese batteries (or more often, ground power) are used to first start a small turbine engine in the tail (APU) which generates the compressed air used to start the main engines. Further reading: http://en.wikipedia.org/wiki/Auxiliary_power_unit http://en.wikipedia.org/wiki/Auxiliary_power_unit Edit: after further research, it seems compressed air is not used on the 787. It's all electric (two generators on the APU and on each engine): "The power source for APU starting may be the airplane battery, a ground power source, or an engine-driven generator. The power source for engine starting may be the APU generators, engine-driven generators on the opposite side engine, or two forward 115 VAC ground power sources. The aft external power receptacles may be used for a faster start, if desired."[1] 1. http://www.boeing.com/commercial/aeromagazine/articles/qtr_4_07/article_02_4.html http://www.boeing.com/commercial/aeromagazine/articles/qtr_4...
- jlgreco 14y agoAhh, that makes more sense. Thanks!
- WalterBright 14y agoEarly jet aircraft used a ground cart to provide power to get the engines started. Evidently adding the APU saves enough money to justify its significant weight.
- tfe 14y agoI think it's less about money and more about stuff like: - backup power for emergencies - allowing attempted engine restarts in the air - allowing the airplane to be self-sufficient should it be forced to land somewhere without ground equipment (or big enough ground equipment)
- moreati 14y agoFrom the captions, this battery starts the APU (and in an emergency, critical systems). The APU starts the main engines http://en.wikipedia.org/wiki/Auxiliary_power_unit http://en.wikipedia.org/wiki/Auxiliary_power_unit