Evergreen B747 Supertanker is the World's Largest

 - Jun 14, 2009
References: fire.uni-freiburg.de & popsci
The guys at Evergreen Aviation aren’t fooling around when they build a flying fire extinguisher. Their 747 Supertanker can carry and, more importantly, dump 20,500 gallons of water from 500 feet. This deluge of water would be a savour to firefighters worldwide.

The airplane would be indispensable in the case of a powerful localized fire dropping up to 7 times the amount of water that the current blaze battling aerial arsenal is capable of.

Images 2-8 were taken by Rob Cockerham of Popular Science while he was lucky enough to witness a performance of the Evergreen Supertanker doing its thing.