Updated on June 20, 2016

Boeing is modifying 30 legacy F/A-18C Hornets recovered from the aircraft “boneyard” at Davis-Monthan Air Force Base to a “C+” standard at the request of the U.S. Marine Corps. The updated strike fighters will support two new squadrons, the manufacturer said.

Thus far, Boeing has delivered two F/A-18C+ fighters to the Marines from its maintenance facility at Cecil Airport, Fla. Five more fighters were undergoing the update and four were expected to arrive by September.

“They’re expecting a combat-capable aircraft on delivery,” said Bill Maxwell, Boeing senior manager of Cecil Airport F/A-18 operations. “That’s our contract to them.”

Under the so-called C+ reconstitution program awarded to Boeing in 2014, the legacy Hornets are being trucked to Cecil Field from the aircraft boneyard near Tucson, Ariz. They are fitted with new avionics and a modernized AN/APG-65 radar. Modifications also extend the service life of the fighter from the current 6,000 hours to 8,000 hours.

Maxwell said F/A-18Cs arriving from Davis-Monthan AFB are generally lower-time fighters that hadn’t reached their full service lives. Boeing overhauls legacy Hornets as well as F/A-18E/F Super Hornets at Cecil Airport (formerly Cecil Field before being renamed by the Jacksonville Aviation Authority in 2011). The manufacturer said 47 fighters were undergoing repairs in multiple hangars.

The facility also modifies retired Lockheed Martin F-16s to the unmanned QF-16 aerial target for the U.S. Air Force. Thirteen of 97 conversions have been completed, Boeing said.