The Air Force's main F-35 schoolhouse is constantly setting records, officials like to boast. The most F-35 sorties in one day, in one week and in one month.

There's been a continuous stream of pilots and maintainers coming through classes at here with the sole focus on helping the Air Force get ready for its deadline of initial operating capability next summer, according to said Col. Todd Canterbury, the outgoing commander of the 33rd Fighter Wing at Eglin that oversees all the training.

"We've taken this airplane from having nine, to a full complement of 26 A models and 17 C models," Canterbury said. "We are flying large force exercises, F-22 integration sorties, we're training students on a regular basis. We've really operationalized the airplane."

But the service is facing a short deadline and a continued shortfall for its IOC deadline, putting the milestone in jeopardy since it has been unable to finalize a plan to get enough airmen available to work on the plane in time.

This North Florida base has been the hub of all F-35 training since the first jet landed in 2011. All pilots, save for a few test pilots, have cut their teeth at Eglin, with a total of 163 trained. Every maintainer who has turned a wrench on the jet has learned to do so at this base's schoolhouse, with 1,988 maintainers trained as of June 10.

The mission began with hand-selected experts from across all services, picked because of their experience and expertise to come down and kick off the program. Now, however, the base is training pilots, who have just joined the military, and Air Force maintainers straight from tech school, who have not worked on another aircraft before.

"It's very exciting to have brand new men and women because they don't have the former airplane baggage, or luggage, or skeletons in their closet," Canterbury said. "These young kids coming in don't have that baggage."

Eglin is home to the military's oldest variants of the plane, running the first version of the software, or block 1B. About 50 percent of the fleet has been upgraded to the Block 2B package, which expands the flight envelope and sets the stage for more weapons integration. The U.S. Marine Corps will hit its first initial operating capability with this software package later this year. The Air Force will follow suit next year with an upgraded version, called Block 3i, next year.

The pilots are learning to fly with the expanded capabilities, which will include the ability for non-test pilots to drop weapons at Eglin later this year.

"They're expanding the mission set in those large force exercises, deployments to Nellis (Air Force Base, Nevada), integration with F-22s," Canterbury said. "We're learning what the airplane can do."

But the software upgrade timeline has been a tough schedule to follow, namely because of the complexity of the aircraft. The aircraft's millions of lines of code built into its systems have been complex to work through and caused multiple delays. The F-35 Joint Program Office director, Lt. Gen. Christopher Bogdan, has said delays on the next two blocks could impact the release of the biggest software upgrade, Block 3F, which will include full weapons capability and will be used for the Air Force to declare its fleet fully operational.

The Air Force's biggest challenge to meeting its initial operating capability on time is trying to find enough maintainers to work on the aircraft.

The service had planned to retire its fleet of A-10 Thunderbolt II attack jets to free up enough maintainers to train on the F-35 and be ready to stand up the first operational squadrons at Hill Air Force Base, Utah. But Congress has blocked the A-10 retirement plans.

The service has said it needs 1,100 trained maintainers to be ready to meet the summer 2016 deadline. As of June 10, the Eglin schoolhouse has trained 691 maintenance personnel. These have been new airmen coming straight from tech school, along with some more experienced airmen who have moved from other aircraft.

The service has been able to move 18 A-10s to backup status, which has freed up another 150 personnel. The service needs to finalize a plan by the end of the summer to make the deadline, Maj. Gen. Jeffrey Harrigian, the director of the Air Force's F-35 Integration Office, said last month.

"It's a double-edged problem," Canterbury said. "It's a capacity or quantity issue. We can produce a large number of maintainers, the problem is I don't have the experience spectrum to build a squadron. You don't want to have an entire squadron of maintenance folks who are 18-year-old two stripers."

Part of the Air Force problem is getting that experience spectrum where I can pull from the A-10 community to get 5,7, 9-level maintainers, instead of brand-new maintainers. … It's not just an easy problem of 'Why can't you produce more?' I can't produce a 20-year cultured maintainer in three weeks here."

The Eglin schoolhouse has produced 1,900 total maintainers, including the Air Force, Marine Corps, Navy and partner nations. The goal is to, by 2018, produce 2,100 maintainers per year for the F-35.

The maintainers working with the 58th Fighter Squadron here are laying the groundwork for decades of maintenance on the jet that is projected to be the backbone of the service's fighter force.

"Everybody learns every day," said Airman First Class Emily Peil, aircraft maintenance journeyman with the 33rd Aircraft Maintenance Squadron. "Pilots, tech sergeants, airmen. Everybody learns every day."

Staff Sgt. Danny Pereira, a dedicated crew chief with the 33rd Aircraft Maintenance Squadron, recalls early 2011 when the squadron has two jets that they weren't allowed to touch. Since then, the program has moved away from almost exclusive work by Lockheed Martin contractors to an "organic" system where everything is handled by the Air Force.

"The more we went organic, the better it got, the more sense it made," he said.

As the maintainers honed their ability, and the base received more jets, the airmen were able to turn them around for more and more sorties. In 2013, the base's nine jets flew four times per day. On June 8, the base flew 19 sorties.

"Now we are flying 10 of our 25 aircraft in the first go, something we've only done once or twice before," Lee said. "That's where we are trying to go."

Another big challenge was something intended to make airmen's jobs easier: the next-generation maintenance system known as the Automated Logistics Information System. Airmen plug the system into the jet, and it's expected to outline what is and isn't working and streamline the process for getting replacement parts. Airmen earlier this year told members of the House Armed Services Committee that there has been a systemic issue of the system providing "false positives," or issues that aren't actually true.

Pereira said his biggest issue has been the system's frustratingly slow interface. It has since improved. Lee said the airmen at the base have now been visiting Lockheed Martin labs to provide feedback on how to improve the system.

Fiery setback

The base saw one of its biggest setbacks last summer when one F-35, tail number 10-5105, caught fire during takeoff June 23, 2014. The pilot was able to abort takeoff and exit the jet. Three-fourths of the jet was burned, with a loss of at least $50 million. An Air Force Accident Investigation Board Report, released earlier this month, said the fire was caused by part of the jet's engine turbine breaking free, severing fuel and hydraulic fluid lines, sparking a fire.

Following the mishap, Air Force maintainers were forced to do a deep investigation of the engine with a borescope after every three flight hours. That slowed things down because aircraft were flying one and a half hour sorties twice a day — which required an in-depth inspection overseen by Pratt & Whitney personnel and videotaped every day. That now has been eased to every 13 hours, Lee said.

Pilots saw their flights severely limited following the mishap. Pilots initially could not fly faster than Mach .9, and were limited to maneuvers less than 3 Gs. Pilots are now able to fly within their normal training envelope, Canterbury said, and will soon see new freedom in the cockpit. With a small software upgrade, to Block 2B 5.2, pilots will be able to fly up to 7.5 G maneuvers and a higher angle of attack, along with the ability to release weapons. This will address one of the biggest concerns of the aircraft: its close air support ability.

"CAS is all about weapons effects for the troops on the ground," Canterbury said. "It doesn't matter what platform delivers those effects, as long as those effects are delivered in a timely manner, in a precise manner and when it is needed. The F-35 brings all access, at night, in weather and in a high threat environment where other platforms may not have that capability."

F-35 pilots fly close air support training sorties every week, and have done practice missions with special operations troops at Hurlburt Field, Florida, along with bringing Army soldiers and Air Force joint terminal attack controllers to train at the range here. However, pilots still have not been able to release weapons and will not see a full weapons load out until later software packages.

Canterbury is an F-35 pilot with 200 hours in the aircraft, but he flew his final flight in the jet June 11. He has been selected for a staff position at the Pentagon to continue the F-35's integration, and he will face tough resistance from critics in Washington, especially those on Capitol Hill. He will pitch that be airmen are flying the aircraft daily, developing how it will fly to give the larger military a better picture of how the jet will operate. It is still developing, and will prove its worth, he said.

"The only way this airplane will fail is if we fail to fund it correctly," Canterbury said.