EGLIN AFB — As President Trump's nominee for defense secretary is telling the Senate Armed Services Committee that the F-35 Lightning II stealth fighter jet won't meet a Pentagon goal for an 80% mission-capable rate across all military services by Sept. 30, the 33rd Fighter Wing at Eglin Air Force Base is nonetheless flirting with that number.

In April, the 33rd — a graduate flying and maintenance training wing — posted a 77.1% mission-capable rate for the 33 F-35s on its flight line, according to Lt. Savannah Stephens, the wing's public affairs officer. That's the highest mission-capable rate achieved by the wing since August of 2016, when the Air Force declared initial operational capability status had been reached for the F-35A, the Air Force's version of the jet.

For June, the 33rd Fighter Wing's F-35 mission-capable rate was down just slightly, to 76.8 percent, according to Stephens.

"Our trend over the last year has been getting closer and closer to the 80% mark, and that is a huge win for our wing," Stephens said in an email. "We’re at the highest MC (mission-capable) rates we’ve ever had."

Different versions of the jet are flown by the Marine Corps, which operates the F-35B, a short take-off and vertical landing jet, and the Navy, whose F-35C can land on an aircraft carrier.  

In order to be mission-capable, an aircraft must be able to perform at least one of its designated missions. The F-35's missions include air-to-air and air-to-ground combat as well as intelligence, surveillance and reconnaissance.

At Eglin and elsewhere across the military services, a lack of availability of spare parts has hampered the F-35's mission-capable rates. Last year, U.S. Rep. Matt Gaetz, whose district includes Eglin, raised concerns that the basen could miss its goals for graduating new F-35 pilots as a result of the parts shortage. Eglin is one of two Air Force bases — the other is Luke Air Force Base in Arizona — that train F-35 pilots.

Stephens said Wednesday that the supply issues that had affected Eglin's F-35 operations have eased in recent months.

"We're doing what we can and turning jets," said Stephens, referencing the cycle of getting jets' maintenance needs addressed and returning them to service.

But Stephens also cautioned that when the deadline for 80% mission capability arrives, Eglin might not meet that goal. There are a number of reasons for that, including routine maintenance scheduling that might keep a number of F-35s out of the sky, she said.

The 80% mission-capable target was set by former Defense Secretary James Mattis last September, when the mission-capable rate for the Air Force's F-35s was at 54.7 percent. Air Force officials have since said that the service is on pace to meet Mattis' goal.

But earlier this week in a letter to the Senate committee, Mark Esper, President Trump's nominee for secretary of defense, said that problems with maintaining a specialized canopy on the F-35s flown by all of the military services meant the jet would not meet the readiness target across the military services.

Esper's letter came on the heels of an April report from the federal General Accounting Office that noted that "shortages, repair backlogs, and mismatched parts are keeping F-35s on the ground."