The Navy has ordered seven more P-8A Poseidon aircraft under a low-rate initial production (LRIP) contract with Boeing [BA], the Pentagon said last week.

The $1.3 billion LRIP 2 order was an extension of the LRIP 1 contract that has Boeing building six of the P-8As. The intelligence, surveillance and reconnaissance (ISR) airplanes are intended to replace the legacy fleet Lockheed Martin [LMT]-built P-3 Orions, which have been operating for decades.

The Navy plans to buy 117 P-8As. The work on LRIP 2 is expected to be complete in January 2013, the Pentagon said.

The P8-A is a derivative of the 737. The first of the planes is expected to reach initial operational capability (IOC) in 2013. The P-8As, like the P-3s, are also designed for anti-submarine and anti-surface warfare.

Four of the test planes are undergoing test flights at Naval Air Station Patuxent River, Md.

The total work for the U.S. Navy program could add up to $15 billion if all 117 production-model airplanes are purchased.

Boeing’s P-8 industry team includes Northrop Grumman [NOC], Raytheon [RTN], Spirit AeroSystems [SPR], BAE Systems and GE Aviation