Above: Air tanker 137, a 737-300, at the grid test near Lancaster, California, September 3, 2018. Coulson photo.
Coulson Aviation posted these photos September 3, 2018 of one of their recently converted 737-300’s, Tanker 137, as it was undergoing grid testing in Lancaster, California.
The process involves dropping retardant over a grid of thousands of cups intended to measure the volume and consistency of the pattern when it hits the ground. The Interagency AirTanker Board requires passing this and other certifications before an aircraft can be “carded” as a federal air tanker, which makes it eligible for a contract to fight fires.
Some air tankers are required to make 20 to 25 drops over several days at the test. Firefighting hand crews are usually hired or borrowed to retrieve the cups after each drop. It is a very expensive process. The last time we checked the price of retardant was $2.50 to $3.00 a gallon, depending on which air tanker base it is delivered to.
The interior of Coulson’s 737 looks futuristic.
They intend for it to be able to haul 4,000 gallons of retardant, or passengers. Last year Britt Coulson said, “With a full retardant load and 4.5 hours of fuel we are so far under max gross weight we are going to leave the full interior and galleys in even when just in airtanker mode.”
The company purchased six 737-300’s from Southwest Airlines.