US-based aerial firefighting specialist Coulson Aviation (United States of America) (CUL, Portland International) has announced it has acquired six B737-300s from Southwest Airlines (WN, Dallas Love Field) with plans to convert the jets into 4,000-gallon “Fireliner” air tankers.

The firm said in a statement that the first conversion has started, with a freshly painted N617SW (msn 27700) having rolled out of the paint shop in Spokane on May 22, 2017. Gravity-based tanks will be added in the next step. Coulson Aircrane Canada will start the installation of a retardant system in June with a completion date of December of this year. When that is complete, work will start on converting the next aircraft in line, presumably N608SW (msn 27928).

Commenting on the development, Britt Coulson said the air tanker is designed as a multi-use aircraft with the ability to haul passengers.

“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,” he said.

Coulson Aviation operates three Lockheed Hercules C130 firefighters and is currently hunting around the market for more.