Aviation history was made today as a Boeing 747 Supertanker made its debut drop on a live wildfire.
Tanker 979 is a specially modified Evergreen 747 configured to carry 20,500 gallons of retardant, enabling it to lay down a fire line as much as three miles long from an altitude of 300 to 600 feet. (There's a handy FAQ, here.) After years of development, testing, certification, and bureaucratic wrangling, Tanker 979 went into battle for the first time today to help fight the Station Fire that's currently burning in the mountains near Los Angeles.
The Wikipedia explains how the system works:
Current fire fighting aircraft use a gravity drop system. Doors in the underside of the aircraft open, allowing the contents of the tanks to discharge. This type of system requires an aircraft to fly very low, typically 200ft above ground level.
The Evergreen Supertanker has a pressurized system. This can disperse retardant under high pressure, for an overwhelming response, or drop retardant equivalent to the speed of falling rain. This system allows the aircraft to operate within its design criteria.
Using the pressurized system, the aircraft can deliver retardant to the scene of a fire whilst flying at a height of 400 to 800ft, at approximately 140kts(160mph) (260kph), configured as if it were on approach for landing.
The local Fox affiliate in LA captured some vivid video footage of Tanker 979 in action today, so enjoy the view as a very unique 747 gets its first true trial by fire. It looks like CGI animation, but it's very real: