Kawasaki Heavy Industries Ltd. held a ceremony Tuesday in Gifu Prefecture to deliver the first two P-1 next-generation antisubmarine patrol aircraft to the Maritime Self-Defense Force.

The two planes will be deployed to the MSDF Atsugi base in Kanagawa Prefecture and will undergo flight tests for two years before engaging in maritime patrol missions.

Kawasaki Heavy has cooperated with the Defense Ministry’s Technical Research & Development Institute in developing the P-1 turbofan jet to replace the P-3C turboprop aircraft that the firm produced under U.S. license. However, completion of the new plane was delayed for one year due to fuselage cracks.

The four-engine P-1 is the world’s first practical aircraft to use the fly-by-light system that sends signals through fiber-optic cables to control surfaces while preventing electromagnetic waves from the electronic systems from affecting flight control, the firm said. The MSDF plans to replace about 80 P-3Cs with some 70 P-1s.

“The situation has grown severer due to such developments as Chinese government ships sailing into Japan’s territorial waters around the Senkaku Islands,” Senior Vice Defense Minister Akira Sato said at the ceremony. “I’m confident the P-1 will play a core role in securing safety in Japan and the international community.”