Lockheed Martin has approached the US Navy with a proposal to sell ES-3 Shadow electronic reconnaissance platforms as upgraded maritime patrol aircraft (MPA) on the international market. Meanwhile, the navy is preparing to move ahead with its own S-3B Viking improved sensors demonstration.

The US Navy is expected to retire its fleet of 16 modified ES-3 aircraft this year to save costs. The twin-engined jets are likely to go into storage despite there being a "lot of life left in these aircraft", says Robert Weiss, Lockheed Martin S-3 programme manager.

There are "positive indications" that the US Navy might release the aircraft for export sale, he says. The ES-3s, converted from S-3 airframes between 1991 and 1993, could be re-modified to a new international MPA configuration based on the Lockheed Martin P-3 avionics improvement programme (AIP). "We can leverage a lot of improvements made in the AIP and package this into a S-3," says Weiss.

The US Navy's fleet of 113 S-3Bs are the subject of a series of on-going and proposed enhancements aimed at extending the aircraft's service life and coastal warfare capabilities. The package of improvements, which Lockheed Martin has collectively labelled the Viking 21 upgrade, will bridge the gap until the navy can better define a new Common Support Aircraft.

Funded and under way is a critical structures programme focused mainly on wing improvements, which will increase the aircraft's fatigue from 10,000h to 13,000h, sufficient to keep the S-3 in service until 2015. Lockheed Martin will begin full-scale fatigue testing of an S-3 in May. This five-year effort is intended to lead to additional critical structural improvements that would extend the airframe's fatigue life to 17,500h or seven more years, says Weiss.

Improvements are being made to the S-3's core avionics subsystems. These include replacement UHF radios with a satellite communications mode, new VHF communications, an inertial navigation system with embedded global positioning system, a 1553 databus, liquid crystal displays, digital flight data computer and upgraded open architecture mission computer.

The US Navy is also to begin testing a Raytheon APS-137B(V)5 radar-equipped S-3 demonstrator this year at Patuxent River. A separate demonstrator will be equipped with a Wescam television/infrared optical surveillance system and Link 16 datalink.

Source: Flight International