The F-35 has officially been in development since 2001. By the end of 2013, the overall flight test program will be approximately 50 percent complete, according to Lt. Gen. Christopher C. Bogdan, U.S. Air Force, program executive officer for the Lightning II Joint Program Office (JPO).

“We’ve been at this for 12 years and people like myself are losing patience,” he acknowledged at the 2013 Air Force Association (AFA) Air & Space Conference in mid-September. In front of a crowd of representatives from the services, industry, and the media, Bogdan asserted that the Joint Strike Fighter (JSF) program had turned a corner in 2013, accelerating development and production, racking up flight time, improving the program’s culture, and bringing down cost.

The threats to the JSF are not merely internal. Despite its priority and a difficult diversion of resources by the Pentagon to ensure its unabated continuance in 2013, the JSF program looked to remain under pressure from further budget cuts in 2014. Whatever budget deals are reached, the pace of change within the F-35 program will have to continue accelerating.

But real risks remain, including reliability/maintainability issues and software development progress, both of which could disrupt a stable but fragile in-service schedule and affect the costs underpinning the program. The risks are uncomfortable for a weapons system that the Department of Defense (DoD) considers its absolute first priority.

The threats to the JSF are not merely internal. Despite its priority and a difficult diversion of resources by the Pentagon to ensure its unabated continuance in 2013, the JSF program looked to remain under pressure from further budget cuts in 2014. Whatever budget deals are reached, the pace of change within the F-35 program will have to continue accelerating.

Bogdan conceded as much at the AFA conference. During his speech a year earlier, he had said he purposely “threw a hand grenade” to shake up the program.

“A year later, a lot of things have changed,” Bogdan observed. “Some things haven’t changed fast enough.”

DoD “re-baselined” the F-35 in 2012, adding more than $6 billion in funding and two-and-a-half years to the program. From the new baseline, the JSF has made progress, Bogdan said. That assertion was surely a hard sell as 2013 opened. On Feb. 21, test flights and all training flights were suspended after a 0.6-inch crack was found on a third-stage turbine blade of a test aircraft at Edwards Air Force Base (AFB), Calif., during a routine inspection.

Tests by Pratt & Whitney found the failure to be an exception for a particular engine that “had been operated for extended time in the high temperature environment in its mission to expand the F-35 flight envelope.”

Flying resumed on March 1, but the suspension added to pressure from program critics, who noted that the advent of sequestration cuts on the same day could trigger the kind of “death spiral” (cuts in aircraft orders that increase unit cost, engendering further cuts and so on) that gutted the F-22 Raptor.

Six months later, Bogdan insisted that the program will not be afflicted by a death spiral scenario.

“There is no indication that the U.S. Air Force, Navy, or Marines are going to stop buying F-35s any time soon,” Bogdan said. Delayed buys in the near term, perhaps by the Navy, could drive up unit costs, he allowed, but he indicated that the possibility was unlikely.

Operational testing commenced at Edwards AFB in early March with the arrival of a pair of F-35As. The actual introduction of aircraft to the 31st Test and Evaluation Squadron exemplified the increase in airframe numbers in the overall test fleet, and the resulting ability to conduct flight tests more efficiently. During the year, the program completed departure testing, air-start testing, refueled with every type of U.S. tanker, and completed a second at-sea test on the LHD USS Wasp.

“The airplane is flying beautifully in [the stall] regime,” Bogdan said. “You can talk to all the test pilots and they’ll tell you it’s a very docile airplane once it departs. We’ve shut down the engine many times in flight, and when you do that in a single engine airplane, it’s a significant emotional event. We’re very happy to be through that cleanly.”

“The airplane is flying beautifully in [the stall] regime,” Bogdan said. “You can talk to all the test pilots and they’ll tell you it’s a very docile airplane once it departs. We’ve shut down the engine many times in flight, and when you do that in a single engine airplane, it’s a significant emotional event. We’re very happy to be through that cleanly.”

The flight clearances, including night and weather clearances, allow the exploration of operational concepts, which the Air Force’s 422nd Test and Evaluation Squadron began at Nellis AFB, Nev., in early April. The 422nd will assess the best ways to integrate the F-35A with advanced training programs such as the USAF Weapons School, Red Flag and Green Flag exercises, and with other aircraft in the Air Force inventory.

Weapons separation testing went forward through the year, kicked off by successful completion of separation of the AIM-120 Advanced Medium Range Air-to-Air Missile (AMRAAM) from an F-35B (BF-3) over water in the Atlantic Test Ranges in March. The -B became the first variant to complete separation testing with three different munitions. In June, an F-35A (AF-1) achieved the first successful in-flight missile launch with an AIM-120, which it fired from its internal weapons bay over the Point Mugu Sea Test Range. The next major weapons test, Bogdan explained, would take place in the fall, when the aircraft would “drop a weapon and hit something we intend to hit.” That test was completed Oct. 29, when a Marine Corps F-35B successfully dropped a GBU-12 Paveway II laser-guided bomb on a tank target at Edwards AFB. An F-35A successfully completed a live firing of an AMRAAM at Edwards the next day, tracking a target drone before the missile was command detonated to save the drone.

Mission systems development is key to operating the F-35, and Bogdan revealed that the program has managed to have as many as five aircraft passing information to each other in flight.

“That’s a big deal for us. This airplane is so darn smart, if it can’t talk to other people, we will lose some huge capability in the future on making the whole fleet and the whole battlespace smarter.”

But challenges in achieving such information exchange and threats to the concept itself persist. The F-35’s touted Autonomic Logistics Information  System (ALIS), which monitors, predicts, and communicates an aircraft’s functional status through real-time datalinks, was not capable of sharing data from the airplane as of August. According to published reports, the hardware required to download ALIS data and service the aircraft needs to be made smaller, while the software needs to be made more secure.

One of ALIS’ competitive advantages is that it allows F-35s to share status data with a base or ship they are returning to so that support elements can have tools, parts, and munitions ready to repair and turn around the aircraft as quickly as possible. The data-sharing requires a modem, however, which is vulnerable to hacking.

Marine Corps Deputy Commandant for Aviation Lt. Gen. Robert E. Schmidle told the media, “I think conceptually it makes a lot of sense, but we have to be very mindful of someone wanting to do nefarious things inside the networks.” The general acknowledged that ensuring network security and designing robust software would be difficult, and that the Marines, who will reach initial operational capability (IOC) first, are watching the issue closely.