For over half a century, the P-3 Orion, an Anti-Submarine patrol plane developed from the Lockheed Electra airliner, has supported the Navy’s Maritime Patrol mission. Intended as a sub hunter, the Orion also performed surveillance of surface shipping in both open water and in the littorals, most famously in the Cuban Missile Crisis but also along the coasts of Vietnam. In the past decade, the Orion fleet has provided yeoman service providing overland Intelligence, Surveillance and Reconnaissance (ISR) in both Afghanistan and Iraq.
But the Orion fleet is aging and worn out. And so the time has come for its replacement to arrive. And so the Boeing 737 has been adapted as the P-8A Poseidon. In development the last few years, the first few Maritime Patrol squadrons have transitioned from the P-3 to the P-8. And as of yesterday, VP-16 achieved Initial Operational Capability, and has forward deployed two Poseidons to Japan.
Still, it will take several years for the Orion community to transition. The last P-3s are currently scheduled to retire in 2019.