Competition is the mother of invention, and with a handful of prime contractors chasing fewer new programs, none are willing to pass on a chance to compete, even if it means dusting off an old product.

An example is the U.S. Navy's emerging requirement to renew its carrier-onboard-delivery (COD) fleet. Northrop Grumman is proposing to remanufacture the existing C-2 Greyhounds, while the Bell Boeing team is offering new V-22 Osprey tiltrotors.

Now Lockheed Martin has entered the fray with a proposal to take U.S. Navy S-3 Vikings out of desert storage, refurbish them and fit them with a new, larger fuselage suited to the cargo role. Retired from carrier decks in 2009, the twin-turbofan S-3 was designed for anti-submarine warfare but was also used for cargo delivery, electronic intelligence and aerial refueling.

And the Navy is not the only possible customer for the rejuvenated S-3s. South Korea plans to introduce more than 20 Vikings into service in 2018-20 as second-tier maritime patrollers, apparently in response to the loss of a warship to a North Korean submarine attack three years ago. The S-3s are a cheaper option than refurbishing and upgrading more Lockheed P-3 Orions.

First flown in 1972, the S-3 was retired for economic reasons, to reduce the number of aircraft types on carrier decks, and not because it was running out of life. There are 150 Vikings in storage, 90 of which are viable for refurbishment, with an average 7,000-9,000 hr. of airframe life remaining, says Clay Fearnow, business development lead for the P-3 and S-3.

Lockheed Martin's KC-3 proposal for the Navy COD mission would reuse the S-3's cockpit, wing, tail, engines and landing gear, but mate them to a new wider and longer fuselage with a rear loading ramp. “We've done the high-level engineering on whether it can take the cat and trap loads, and we believe it will,” Fearnow says. “We've run the concept past the Navy and responded to the RFI [request for information].”

The KC-3, with its new aluminum fuselage, would actually be lighter than the S-3, once all of its mission avionics are removed, says Fearnow, but more work needs to be done on engineering the modification and assessing the condition of airframes and engines in storage. “We're not completely there yet. We believe it can be cost-competitive, but we have off-ramps in case we do not go forward,” he notes.

Part of Lockheed's offering rests on the S-3's capability as a tanker, a secondary requirement in the COD RFI. The ability to carry two underwing hose-and-drogue pods was demonstrated during development of the Viking but never fielded operationally. The KC-3 would be able to carry the required 10,000 lb. of cargo—or 21,000 lb. of fuel, 17,000 lb. in internal and external tanks plus 4,000 lb. in palletized tanks.

With the KC-3, as with the V-22, comes the potential for the Navy to change its hub-and-spoke COD operating concept, now built around C-2s flying time-critical parts and supplies to the carriers from logistics bases ashore. Once delivered to the carrier, loads are broken up and parts forwarded to other ships via helicopter. The V-22 offers the possibility of flying materiel directly from where it is held to where it is needed.

The KC-3 would still have to fly to the carrier but has twice the range of its competition, he says. “That would give more maneuverability and options to the carrier,” Fearnow says. “It also could reduce the basing requirements, from 10 to maybe five.” The faster, jet-powered KC-3 would also fit into the normal carrier launch-and-recovery cycle, he says.

Putting the Viking back into Navy service as a transport/tanker (the service still operates three as range-support aircraft) could reduce operating costs for South Korea, meanwhile, although the S-3's General Electric TF34 engine is used on U.S. Air Force A-10 attack aircraft and, in its civil CF34 variant, on regional jets.

South Korea's Defense Acquisition Program Agency said earlier this year that options for its requirement for “20-plus” lower-tier maritime patrol aircraft included the Airbus C295, Boeing P-8 Poseidon and Lockheed Martin SC-130J Sea Hercules. The latter two looked too expensive for the program budget of 1 trillion won ($940 million), but that would be enough to refurbish and modestly modernize the S-3s.

The requirement is known as Maritime Patrol Aircraft Batch 3. Batches 1 and 2 were two lots of Orions: eight second-hand P-3Bs that were refurbished and upgraded last decade to a standard called P-3CK and eight P-3Cs that were bought new in the 1990s and are now being upgraded to the CK standard.

The Viking's mission will be sea surveillance and anti-ship and anti-submarine warfare. North Korean submarines are difficult targets for the South Korean navy. South Korean ships detected only 28% of North Korean subs exercising in the first quarter of 2010, a member of the National Assembly's Defense Committee said in 2011. North Korea has about 70 submarines. Most are small and all are rudimentary, but one torpedoed and sank the South Korean corvette Cheonan in March 2010, killing 46 sailors.