LONDON - The U.K. Royal Navy has formally declared its newly upgraded Merlin Mk. 2 anti-submarine warfare (ASW) helicopters to be in service, and is considering adding aircraft to what will become one of the U.K.'s hardest-pressed assets.

The navy declared an interim operating capability with the Merlin Mk. 2 on June 30, four months early and just days after the navy completed the largest-ever deployment of Merlins as part of Exercise Deep South in the Eastern Atlantic Ocean. Nine aircraft flew 480 hr. during the deployment on HMS Illustrious on June 2-26.

Commander Ben Franklin, commander of the U.K.’s Navy Merlin force, said the aim of the exercise had been to test the capabilities of the upgraded helicopter. “The Merlin’s role in defense is extremely complex … In our demanding maritime environment, we had to generate and deliver until complexity becomes routine, and that was one of the challenges of Deep Blue,” he said.

Lockheed Martin, and its subcontractors including OEM AgustaWestland were contracted under the £750 million ($1.28 billion) Merlin Capability Sustainment Program (MCSP) to convert 30 Merlin Mk. 1s to the Mk. 2 standard with a new mission system and cockpit avionics. The aircraft also are being fitted with multi-static processing for the acoustic system and are receiving improvements to their survivability and intelligence-gathering capability with an electro-optical camera. The last of the 30 is due to be delivered back to the Royal Navy next year.

The Royal Navy has eight aircraft, which it did not plan to upgrade, left orphaned. But navy officials have requested that at least a handful of those orphaned aircraft get upgraded to the Merlin Mk. 2 standard.

“Whether it is two, four or eight aircraft, that get converted, it is not clear, but we are confident,” said Capt. Ed Trischler, the Merlin Team Leader at the U.K.’s Defense Equipment and Support Agency. A decision is expected later this year.

In the current fleet configuration, 25 Merlin Mk. 2s need to be available at readiness with five in maintenance. Of those 25, 14 will be dedicated to the new Queen Elizabeth-class aircraft carrier when that ship puts to sea as part of a task group, with aircraft configured for the ASW role and the airborne early warning mission, equipped with the radar system selected through the Crowsnest program.

Two options are being assessed and the first, Lockheed Martin’s podded radar solution, will conduct flight tests in the coming weeks. Flight tests of the Thales solution using the Searchwater currently in use on the Royal Navy’s Sea King Mk. 7s will follow.

Lockheed Martin officials would not say which radar would now feature in their solution.

The company had originally hoped to use Northrop Grumman’s APG-81 radar from the F-35 but was forced to select different radar instead, believed to be an Israeli Elta-made system.