The oldest of the Navy's workhorse M-60 Seahawk helicopters are well into the final decade of their planned 30-year service lives, and Navy officials are starting a review to see what's needed to keep them in the air for as long as two more decades.

The two models, MH-60R and MH-60S, are responsible for everything from submarine hunting and vertical resupply to plucking a man overboard out of the water and the service will need to keep them in service until two decades from now when a suitable replacement helo is ready.

To keep the aging air frames flying, Naval Air Systems Command will first have to undertake a service life assessment to see how much wear and tear they've accumulated over the years.

"That will determine how long the aircraft will last, and what activities we need to take to make the aircraft last that long," said Capt. Craig Grubb, the H-60 program manager, at the annual Sea Air Space symposium outside Washington, D.C.

Right now, that's looking like the 2035 time frame, he said, before a follow-on helicopter hits the fleet, but they won't have a flight-hour count until the studies are done.

"If you asked any number of people, you would get a different number of hours," Grubb said

Once NAVAIR has figured out how much life they have left, the service life extension program will take over. The airframes were designed for 10,000 hours, or about 30 years — the MH-60R hit the fleet in 1984, followed by the MH-60S in 2001.

The S variant is up for overhaul first, as it's had the most intense workload since it replaced the CH-46 Sea Knight as a vertical replenishment, adding missions like search and rescue, anti-surface warfare and close air support since.

In March, NAVAIR put out a solicitation for a fatigue analysis report, part of the SLEP process, expecting to award the contract by the end of the year. That would put the SLEP on schedule to begin in early 2021.

MH-60R, though an older airframe, was one of several in the anti-submarine warfare and maritime strike game until the SH-60 sundowned last year. Now that it's the only helo doing that mission, it's going to need an extension as well.

An FLA contract is expected, Grubb said, with SLEP getting underway in 2022. The Navy has some idea of what to expect from the R variant, Grubb said, because they are modeled after legacy airframes like the SH-60B, SH-60F and HH-60H. The S is less predictable, he added.

Additional upgrades

Extending aircraft life is the top priority, but funding the plan opens up other possibilities.

"So as we're going in and SLEPing the aircraft, it's a great opportunity to go in and make upgrades beyond the aircraft and the airframe," Grubb said, including updates to avionics, mission systems and other capabilities.

The hope is that any new technology would then translate to whatever replaces the MH-60s in the 2030s, Grubbs said.

"Into 10 years and beyond, how do we build in capabilities to set ourselves up for whatever's next?"

That could be an MH-XX program, a tiltrotor platform or another vertical lift airframe altogther, but Grubbs said he could not elaborate this early in the process.