The Thomas Fire, sweeping over 282,000 acres in California, is finally 100% contained. Throughout the course of the biggest fire in California history that claimed 46 lives and over $13 billion in damages, firefighters deployed a number of aerial devices to stop the blaze, including most notably a Boeing 747 supertanker.
The plane is owned by Global Supertanker, the successor to the defunct Evergreen Supertanker Services who first developed 747 Supertanker for aerial firefighting. It is remodified from a commercial Boeing 747-400 with sprayer tank system transplanted in from a previous 747-100 supertanker.
The 747 Supertanker can carry up to 19,600 gallons of retardant or water for over 4000 miles, doubling the loading capacity of the second largest air tanker, a DC-10. In the Thomas Fire, the 747, aka The Spirit of John Muir, took off from Sacramento and reached fire scene after 38-minute cruise at 600-mph. Then it followed a lead plane to make drops at designated areas from only about 200 feet up, ensuring the 2-mile drop of retardant was a solid one to contain fire from spreading further. The whole drop was controlled to within 10 minutes before the plane heading back to Sacramento.
The 747 is equipped with 8 tanks, meaning it can also be used in smaller and separate fires on one trip. Yet smoke and high wind can render the drop mission ineffectual. "The limitations are not on the aircraft. It's really on the retardant. If it gets really windy, the retardant can't lay down the line that it needs to lay to help those fire fighters on the ground. " said Valdez the pilot of the supertanker.
The Supertanker service was initially purchased on a contract-on-demand, until the Cal Fire leased it for a year to fight wild fire. It is reported to cost $50,000 per day on standby and $15,000 per flight-hour.