The biggest fire-fighting jet on the planet started duty Monday combating the deadly fires around Los Angeles. It is a converted Boeing 747, dubbed Tanker 979.

If it performs as well as expected over the next few days, it could not only mean less destruction of buildings and lives, but big business for the plane’s owner, McMinnville, Oregon-based Evergreen International Aviation.

Fighting fires from helicopters and planes is not new, but nothing comes close to the fire-snuffing capacity of this former freight jet.

After a design and conversion process that cost $50 million, according to the private company’s chairman Timothy Wahlberg, the supertanker can spray 20,000 gallons of flame retardant from four-16-inch nozzles mounted on the fuselage in a pattern that amounts to a rain shower the width of a football field and three miles long.

To put that in perspective, a converted DC-10 that was used to fight fires in California a few years back had about half the capacity, and the typical fire-fighting plane used in forest fires, the P-3 Orion (developed in the ‘60s by the U.S. Navy for ship and submarine reconnaissance), has a capacity of about 3,000 gallons.

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Unlike other fire-fighting planes in use, which use gravity to dump their liquid cargo all at once from a fairly low altitude of a few hundred feet, Tanker 979’s payload is released under pressure from onboard compressed air tanks. That means that the jet can fly at a relatively high 600 to 800 feet spraying its payload as it goes, making it safer in theory, even suitable for firefighting at night.

The fire-fighting muscle of Tanker 979 does not come cheap. One report, has it costing about $1 million each time the plane is activated for a drop from its current home at McClellan Air Force Base near Sacramento, Calif. Wahlberg would not say what the State of California is paying his firm to prep, load and fly the jet, which is under contract until Friday.

“We’ve been paid for three drops so far,” Wahlberg says. “Look, we grub-staked the development of this plane on our own because we thought the firefighting business needed it. Every bit of revenue helps, and we think inside of three years we’ll recover all our research and development money and be on our way.”

So far, it’s doing the job by all accounts, laying down fire lines to protect homes near San Bernardino. “Everybody waits to see what’s going to happen when the plane is working on a real fire,” Wahlberg says. “We’ve got one now, a huge one, and already the calls are coming in.”