Boeing 747 Supertanker – The World’s Largest Fire-Fighting Plane

As California battles some of its most destructive wildfires in decades, a red-and-white liveried 747 has become a frequent sight – and sound – in the smoke-filled skies. The retrofitted passenger jumbo jet roars perilously close to the ground as it releases close to 19,000 gallons of fire retardant. Meet the world’s largest fire-fighting aircraft, the Boeing 747 Supertanker.

the 747 supertanker
The world’s largest fire-fighting plane is currently enlisted in the battle against wildfires in California. Photo: Getty Images

A Queen on a mission

While airlines across the globe are waving goodbye to their iconic 747 passenger jets, one Queen of the Skies is busy providing support to firefighters around the world, saving lives and property as she goes.

The world’s largest fire-fighting air tanker is a Boeing 747-400 with the tail number 944. It was initially built and delivered as a passenger airliner for Japan Airlines in 1992. The iconic quadjet was then converted to a freighter in 2009 and turned into the Supertanker it is today in 2014.

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The interior has been stripped and retrofitted with massive tanks that can hold around 19,000 US gallons (that is close to 72,000 liters) of water or fire retardant.

She was certified for service by the United States Interagency Air Tanker Board in 2016, and is named The Spirit of John Muir, after the (American) “Father of the National Parks.”

global supertanker firefighter
The “Spirit of John Muir” can carry 19,400 gallons of water and fire retardant. Photo: Papito via Wikimedia Commons

Flies configured for landing

The aircraft is equipped to drop both water and an ammonia-based fire retardant and can do so from as low as 200 feet above the ground. Because of this, the Supertanker mostly flies as if it was configured for a landing approach, with flaps and slats extended to maximize lift at low speed. It is said to be one of the most challenging feats for any freighter pilot.

The aircraft has a special pressurized liquid drop system that deposits the water or retardant through four tubes in the bottom of the plane. This allows it to either disperse the retardant under high pressure or let it fall like heavy rain on the ground below. The plane can drop its load either all in one go, or incrementally over various sites.

It can operate anywhere in the world where there is an 8,000-foot runway and facilities for fire-fighting missions by air. Furthermore, the repurposed jumbo can be refilled in as little as 30 minutes.

Almost anywhere in the world in 20 hours

The Supertanker, as she is a 747, can be anywhere in the US within four and a half hours, and almost anywhere in the world in 20, with one stop for refueling. The company that owns her, Global SuperTanker Services, is American and run by firefighting-by-air veterans. However, she flew her first assignments fighting fires in Israel and Chile before being enlisted to help efforts in California in 2017.

Fought fires in the Amazon in 2019

In 2019, the Supertanker was called upon by the Bolivian Government to help fight fires in the country’s Amazon rainforest region. The jet and its 15 person crew were hired on a two-week contract and made four flights per day.

Supertanker 747
The Supertanker has fought fires in Israel, Chile, and Bolivia. Photo: Global SuperTanker Services

The second-to-largest air tankers are the four McDonnell Douglas DC-10 operated by the US Forest Service.

Have you ever seen a fire-fighting aircraft in action? What do you think it would be like to operate one? Let us know in the comments. 

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