The US Department of Defense has approved the possible sale of eight Boeing AH-6I attack helicopters to Thailand as the Southeast Asian nation contemplates its attack helicopter requirements.

The $400 million deal, to be conducted through the US government’s Foreign Military Sales (FMS) process, includes a range of weapons, sensors, training, and other support, according to a Defense Security Cooperation Agency statement.

“These AH-6I helicopters will replace the [Royal Thai Army’s] aging fleet of seven AH-IF Cobra helicopters,” says DSCA. “As part of a broader military modernization effort, these AH-6I helicopters will provide light attack reconnaissance for close air support to special operations forces, Stryker infantry soldiers and border guard units.”

Bangkok issued a request for proposals for eight attack helicopters at the end of 2017, but FlightGlobal understands that the coronation of the country’s new king and a general election have held up the acquisition.

Bell is pitching its AH-1Z Viper attack helicopter for the deal. FlightGlobal understands that other manufacturers such as Airbus Helicopters (Tiger) and Turkish Aerospace (T129) are also interested in the requirement.

Bangkok operates seven AH-1Fs. It had eight, but one was lost in a 2001 crash. Cirium fleets data shows that the average age of its AH-1Fs is 37.8 years.