Australia intends to buy up to eight P-8A Poseidon maritime patrol aircraft that are currently being built by Boeing [BA] for the U.S. Navy, the country’s defense ministry said Feb. 21.

The Royal Australian Air Force would become the second international customer for the aircraft following India, pending an agreement on a contract with Boeing.

Like their American counterparts, Australia would be purchasing the P-8A Poseidons to replace the aging

Lockheed Martin [LMT] P-3C Orion surveillance aircraft.

The Australia government said it expects the first P-8A to arrive in 2017 with all eight becoming fully operational by 2021. Canberra is also keeping an option to purchase an additional four.

“The P-8A is a potent and highly versatile aircraft,” the government said. “As well as patrolling Australia’s maritime approaches it can conduct search and rescue, anti-submarine and maritime strike missions using torpedoes and Harpoon missiles.”

Australian officials estimate the cost of the eight P-8As will be about $3.6 billion U.S. The government projects the P-8A program will bring up to $1 billion in economic revenue at a base in southern Australia and other locations for maintenance and support.

“We look forward to the Royal Australian Air Force’s continued teaming efforts on the P-8 program and we concur that it is the ideal platform for Australia’s maritime patrol needs,” Boeing spokesman Chick Ramey said.

Boeing has delivered three of the eight P-8As planned for India. The U.S. Navy has received 13 of the 37 currently under contract and plans to buy up to 117 of the aircraft.

The P-8A airframe is based on Boeing commercial 737 aircraft.