FORT WORTH – As preparations continue for the first overseas deployment of the F-35B to the U.K., Lockheed Martin has marked the delivery of the 101st aircraft and is working on more than 80 additional Joint Strike Fighters in various states of completion between long-lead assembly and final power-up.

The latest delivery, the 45th F-35A for the U.S. Air Force, was delivered to Eglin AFB, Fla., on May 28 to the 58th Fighter Squadron, which becomes the Air Force’s first complete JSF squadron. The aircraft is also the 26th and final F-35A delivery scheduled for the 33rd Fighter Wing, and "from now on, almost exclusively, we will start filling up Luke AFB with aircraft to get ready for U.S. and international training," Lockheed says. The first F-35A completed its initial training sortie in mid-May at the Arizona site, which will ultimately support six squadrons of 144 aircraft, making it the largest F-35 base in the world.

The 45 F-35As at Eglin also include the initial pair of aircraft for the Netherlands, which are integrated into the 58th Fighter Squadron, while three of the 42 F-35Bs delivered so far have been allocated to the U.K. The three aircraft are also stationed at Eglin, where British Royal Navy and Royal Air Force pilots and maintainers are undergoing training. The U.K. currently plans to acquire 138 F-35Bs with 617 Squadron, the RAF’s first operational unit, due to transition from U.S.-based training to RAF Marham in 2018.

Meanwhile, testing of the F-35B for the U.S. Marine Corps continues to pick up pace, with the first demonstration of the aircraft’s ability to sequentially engage multiple aerial targets using two AIM-120 Advanced Medium Range Air-to-Air Missiles (Amraams). The weapon test, conducted against target drones over the Point Mugu Sea Test Range off the California coast on May 27 by one of the two F-35Bs currently based at Edwards AFB, Calif., was the first live Amraam shot from the short takeoff and vertical landing version, and the first dual Amraam shot by any F-35 variant.

One of the six test F-35As based at Edwards flew the first load of Block 3I mission hardware and software on a flight lasting almost 2 hr. on May 27. The start of flight tests with Block 3I, which requires a modified processor, marks a key milestone in the plan to configure the Air Force fleet with the more capable software system by the time it declares its initial operating capability (IOC) in late 2016.

"The Marines will enter service with Block 2B capability, which incorporates 95% of the planned warfighting capability," Lockheed says. "We will complete -2B testing by the end of this year and will complete the paperwork for the Marine Corps IOC in mid-2015."

As with every other aspect of the F-35 development effort, software testing remains under close scrutiny, particularly as the U.S. Navy intends to go operational with the F-35C in February 2019 with another version dubbed the Block 3F. F-35 Program Manager Lt. Gen. Christopher Bogdan warned earlier this year that "if we don’t do anything else and we just continue to perform the way we are performing right now and not getting any better, we’re going to be somewhere four to six months delayed on that [Block 3F] software. It’s as simple as that."

Testing of the F-35C also marked a major milestone at the end of May when one of the Navy’s four test aircraft based at Naval Air Station Patuxent River, Md., completed a landing at its maximum sink rate test condition of 21.4 ft. per second as part of evaluations of the aircraft’s landing gear, airframe and arrestment system. During the tests, which form part of the buildup to the first planned landings on a Nimitz-class carrier off the California coast in November, the F-35C caught the wire three times, performed several touch and goes and one bolter. Not including the Pax- and Edwards-based test aircraft, Lockheed has so far delivered 14 F-35Cs.

Naval Air Station Lemoore in central California is meanwhile poised to become the Navy’s West Coast base for the F-35C after U.S. Fleet Forces Command issued a recommendation earlier in May that the site become the focus for operations over the alternate at Naval Air Facility El Centro. Under the plan, which could be confirmed by mid-June, some 100 F-35Cs will be based at Lemoore, 30 for a training squadron and 70 for seven fleet squadrons. The aircraft are designed to replace earlier Boeing F/A-18s at the base by 2028.

Production of all F-35 variants is running at three per month, with 33 aircraft delivered in 2013 and the same expected again for 2014. Including the fully approved low-rate initial production Lots 6 and 7, which between them cover 71 aircraft, Lockheed is currently under contract for 166 F-35s. Including an additional 100 aircraft covered by long-lead funding only for follow-on LRIP 8 and 9, the overall tally is 266. "We are in the ‘back and forth’ of finalizing the negotiations [over LRIP 8], but we are optimistic of completing it this summer," the manufacturer says.

Northrop Grumman, which builds the center fuselage for the F-35 at its Palmdale, Calif., site, delivered the 150th unit on June 2. The fuselage, destined for the F-35A AF-68, is the 50th to be delivered by the streamlined production facility over the past 15 months. The Integrated Assembly Line (IAL), which was opened in March 2011 as part of program-wide efforts to cut costs and reduce assembly times, has had a major impact on flow times. Northrop says prior to the IAL it took around eight and a half years from the start of the program to deliver the first 100 fuselages.