Arlington, Va: The Navy and Marine Corps have a plan in place to squeeze more flight time from their older F-18 Hornets, and could use funding for the F-35 Joint Strike Fighter program to pay for it.

Lt. Gen. Terry Robling, deputy assistant commandant for Marine Corps aviation, said today that the services plan to extend the flight time on 150 Hornet fighters up to 10,000 hours.

This new Service Life Extension Program (SLEP) for the F-18 fleet will cover between 40 to 50 Marine Corps jets, with the rest coming from the Navy’s arsenal, the three-star general said this morning.

The F-18 Hornet was designed to fly about 6,000 hours. An initial SLEP effort by the Marine Corps was designed to push those planes up to 9,000 hours to keep the Hornets flying until the Marines get the F-35 Joint Strike Fighter.

The Marine Corps aviation chief estimated this may cost $1.5 billion. Some planes may require more work than others to keep flying up to that 10,000 hour limit.

To pay that bill, Marine Corps and Navy leaders are considering pulling dollars from JSF accounts, Robling said. However, he added that funding could also be drawn from other programs too, but that would be up to the Pentagon and service leaders to decide.

The Marine Corps had planned to get the JSF up and flying by 2012, according to Robling. But cost growth and repeated setbacks in the fighter’s development forces the Marines to delay that deadline to 2015, he said.

While work on the fifth-generation fighter is now ahead of schedule, those past hiccups in the JSF program forced the services to take drastic measures on its legacy Hornet fleet, according to Robling.

Funding issues aside, plans to extend parts of the Hornet fleet could do more harm than good, considering the strain these planes have been put under in Iraq and Afghanistan.

Marine Corps fighter squadrons in Afghanistan have already racked up thousands of flight hours on their legacy Hornets, scraping the ceiling of the 9,000 flight hour cap set under the previous SLEP plan.

Capt. Stewart Wittel, a F/A-18 pilot with Marine Corps Fighter Squadron 224, told me in August during a visit to Marine Corps Air Station Cherry Point that flying that close to the 9,000 hour ceiling is already stressing out the Hornet fleet.

Maintenance crews in Afghanistan were working virtually non-stop to keep those Hornets combat ready, Wittel said.

Keeping up that kind of pace is something the Marines can’t do forever, Maj. Gen. Jon Davis, commander of the 2nd Marine Corps Air Wing, told me during that same visit. “We [need] to bring F-35 into the fleet as quickly as we can, so we do not have to extend the life of those F-18s,” the two-star general said at the time.

While it may not be forever, the new SLEP plan being introduced by the Navy and Marine Corps will keep those old Hornets in the air much longer than they were ever designed to be.

Where is the breaking point? Robling said services are confident it won’t be at 10,000 flight hours. But if the JSF can’t hit that new 2015 deadline set by the Marines, the question remains: How much more can these Hornets take?