Boeing this week began final assembly of the first U.S. Navy P-8A Poseidon production aircraft at its plant in Renton.

The P-8A is the first of six low-rate initial production aircraft that Boeing is building as part of a $1.6 billion contract awarded by the Navy in January.

The Navy plans to purchase 117 of the Boeing 737-based P-8A anti-submarine warfare, anti-surface warfare, intelligence, surveillance and reconnaissance aircraft to replace its P-3 fleet.

“Boeing will deliver this first aircraft to the Navy on schedule in 2012 in preparation for initial operational capability, which is planned for 2013,” said Chuck Dabundo, Boeing vice president and P-8 program manager, in a company press release. “Our team has built seven P-8A test aircraft to date and the process improvements and efficiencies we’ve incorporated will continue to help reduce costs as the program moves forward.”

The Poseidon team is using a first-in-industry in-line production process that draws on Boeing’s Next-Generation 737 production system. All aircraft modifications unique to the P-8A are made in sequence during fabrication and assembly.

The start of final assembly follows Spirit AeroSystems’ delivery of the P-8A fuselage to Boeing. The fuselage arrived via rail car on March 7 and was loaded into a tooling fixture. Boeing workers have begun installing systems, wires and other small parts.

Boeing was awarded a System Development and Demonstration contract in 2004 to build and test six flight-test and two ground-test P-8A aircraft.