They call it a sub-hunter, or a Multi-mission Maritime Aircraft (MMA). It resembles the world’s most ubiquitous jetliner. But the U.S. Navy’s P-8A Poseidon may end up being more than a submarine-fighting replacement for the venerable P-3C Orion. Although some defense programs are over budget and behind schedule, the Poseidon is progressing steadily toward its intended job in broad-area maritime and littoral operations. Moreover, the Poseidon is a likely candidate for other duties, some in other service branches.

First flown April 25, 2009 and built in its own assembly plant in Renton, Wash., the P-8A is a spin-off of the Boeing 737-800 airliner (but with the wing structure of the 737-900 and distinctive, backswept, or raked, wingtips). The P-8A weighs more than a 737-800, but has plenty of power with two 27,300-lb. thrust F-108 (CFM 56-7) turbofan engines. Systems aboard the aircraft include an upgraded AN/APY-10 maritime surveillance radar and signals intelligence solutions.

The U.S. Navy plans to arm the P-8A with the Mark 54 “Fish Hawk” torpedo which, unlike conventional torpedoes, can be dropped from 15,000 feet and guided to a small target at sea. The Navy conducted its first test of a Fish Hawk in May 2008. Speeding up the P-8A would spare the Navy the cost of upgrading Orions to carry Fish Hawks.

The P-8A program got under way with planemaker Boeing building three test aircraft, plus two static-test airframes. The Navy soon added three “production representative prototype vehicle” (PPPV) aircraft to the contract. Participating in the testing phase with Boeing is Navy squadron VX-20 at Patuxent River, Maryland, which lacks an evocative nickname but is called “Force Aircraft Test.”

Adm. Gary Roughead, chief of naval operations, said in 2008 that he faced a “deficit” in maritime patrol aircraft because at least 39 Orions, or one-fourth of the fleet, had to be abruptly grounded due to age-related wing cracks. The Navy is “hurting,” Roughead said.

The P-3C Orion fleet’s average age is 28 years, and the Navy has instituted a number of programs over the years to stretch the aircraft’s service life.

The plan is for the Poseidon to achieve initial operational capability in 2013. A training squadron will stand up at Jacksonville, Fla., as the first Poseidon flying unit. The Navy wants to eventually acquire 117 P-8As. The current P-3C Orion fleet, including the aircraft that were grounded, numbers 154 airframes. Over the course of its production life, the Poseidon will receive incremental technology insertion upgrades.

The Poseidon may mean salvation for Boeing’s presence at Renton, where the company makes no product other than 737 derivatives. (Its other big jets are manufactured in nearby Everett). The Poseidon’s first overseas customer is India: Boeing is committed to deliver the first of eight P-81 aircraft to India within 48 months of a contract signed in January 2009. Other potential purchasers include Australia, Canada and Italy.

But the real future of the P-8A and of Renton is a planned U.S. Air Force version, minus torpedoes but able to carry more avionics, sensors and fuel.

Boeing says it can deliver 17 modified P-8s for the same cost as modernizing the USAF’s17 E-8C Joint Surveillance Target Attack Radar System (Joint STARS) surveillance platforms, which are Boeing 707-320 derivatives. A program to re-engine the Joint STARS fleet, once considered a “done deal,” is being halted in mid-stride because some E-8Cs have structural fatigue issues. Experts say the Poseidon, called “promising” by Roughead, could also be conscripted to replace USAF RC-135 Rivet Joint reconnaissance aircraft.