Evergreen
International Aviation
Boeing 747 Supertanker

The 747 Supertanker is a retired aerial firefighting airtanker derived from various Boeing 747 models. The aircraft is rated to carry up to 19,600 US gallons (74,000 L) of fire retardant or water. It is the largest aerial firefighting aircraft in the world.

The third 747 Supertanker was developed by Global Supertanker Services (which acquired most of Evergreen's assets), who owns and operates the aircraft currently. The Global Supertanker (N744ST, tanker/tail number 944) is a Boeing 747-400 dubbed the Spirit of John Muir. It was certified for firefighting flights by the Federal Aviation Administration in September 2016 and fought fires in Chile and Israel before being contracted by U.S. officials to fight California wildfires in 2017.[6] It also took part in firefighting in Bolivia in August 2019. It was retired in 2021.

Design

The Global Supertanker was equipped with a pressurized liquid drop system, which could disperse fire retardant under high pressure or drop retardant at the speed of falling rain. Using the pressurized system, the aircraft could deliver retardant to the scene of a fire while flying at a height of 400 to 800 feet (120–240 m), at approximately 160 mph (260 km/h; 140 kn), configured as if it were on approach for landing. The Supertanker's tank system could be configured for segmented drops, allowing the contents of the tank to be released at multiple intervals while in flight. According to the company, the aircraft was capable of laying down a swath of fire retardant 3 mi (4.8 km) long and as wide as 150 ft (46 m).