Nov. 18 (UPI) -- India's navy received its ninth P-8i surveillance aircraft on Wednesday, manufacturer Boeing Co. reported.
The plane is the first delivered under an option contract, signed in 2016, for four additional aircraft, the remaining three of which are expected to arrive in 2021.
The Indian navy was the first international customer to receive the plane, in 2013.
The P-8i is modified from the Boeing 737-800ERX passenger plane and built originally for the U.S. Navy. It is used in anti-submarine warfare, anti-surface warfare and shipping interdiction roles.
Armed with torpedoes, Harpoon anti-ship missiles and other weapons, it can drop and monitor sonobuoys, and can operate in combination with Northrop Grumman's MQ-4C Triton maritime surveillance drone.
The new planes of the Indian navy will include electronic surveillance, reconnaissance and jamming capabilities. They will also include encrypted communications systems, a feature available after India and the United States signed the Communications, Compatibility and Security Agreement of 2016.
The encryption allows Indian and U. S. commanders so Indian and U.S. military commanders, and their aircraft and ships, can communicate through secure networks.
The COMCASA agreement, one of several defense pacts between the two countries, facilitates interoperability between their military forces, as well as with other allies using the systems.