The success of the UF-XS's experimental flight prompted the Defense Agency to allocate a full-sized budget for the project to develop new amphibian aircraft for anti-submarine patrols, thus laying the groundwork for promotion of the project through public-private partnership.

In January 1966, we signed a contract with the Defense Agency for development of the first model of our new amphibians and then established a PX-S project promotion committee. With cooperation from Fuji Heavy Industries Ltd. and NIPPI Corporation, we proceeded with the development and manufacture of this amphibian, which made its debut flight on October 17, 1967.
One of the technological requirements of the project was the “ability to take off and land on rough seas with wave height of 3 m.” The takeoff test that we conducted on rough open seas off the Kii Channel in April 1968 was such that it attracted much attention from both Japan and abroad. The record of the test on April 23, when the maximum wave height hit 4 m, stated that they even received the mistaken impression that the PX-S was sinking when it landed. This test served to demonstrate the PX-S's extremely good seaworthiness. After a series of test flights, we delivered the PX-S to the JMSDF in August 1968.
Then in October 1970, the JMSDF gave the PX-S an official name, marking birth of the “PS-1 aircraft.”
“PS” stands for “Patrol Seaplane,” and up until 1979 we manufactured a total of 23 PS-1 aircraft, which were put into service by the JMSDF for anti-submarine patrolling.