Lockheed Martin declared that the F-35 program had completed the “most comprehensive flight-test program in aviation history.” The last sortie in the System Development and Demonstration (SDD) phase took place from NAS Patuxent River, Maryland, on April 11, when F-35C CF-02 collected data on loads that are generated by external carriage of some weapons. According to the U.S. Government Accountability Office (GAO), the SDD phase has cost more than $60 billion, a 50 percent increase on that predicted when SDD started in December 2001 (in FY2017-adjusted dollars).
“Since the first flight of AA-1 in 2006, the developmental flight-test program has operated for more than 11 years mishap-free, conducting more than 9,200 sorties, accumulating over 17,000 flight hours, and executing more than 65,000 test points to verify the design, durability, software, sensors, weapons capability, and performance for all three F-35 variants,” said Vice Adm. Mat Winter, F-35 program executive officer.
“The F-35 flight-test program represents the most comprehensive, rigorous, and the safest developmental flight-test program in aviation history,” said Greg Ulmer, Lockheed Martin’s vice president and general manager of the F-35 program.
According to Lockheed Martin, more than 1,000 SDD flight test engineers, maintainers, pilots, and support personnel took the three variants of the F-35 to their full flight envelope to test performance and flying qualities. The test team conducted six at-sea detachments and performed more than 1,500 vertical landing tests on the F-35B variant. The developmental flight test team completed 183 weapon separation tests; 46 weapons delivery accuracy tests; and 33 mission effectiveness tests, which included numerous multi-ship missions of up to eight F-35s against advanced threats.
Lockheed Martin noted that the SDD will not be formally completed until the Pentagon has performed an Operation Test and Evaluation (OT&E) and cleared the way for full-rate production (FRP). However, nearly 300 F-35s have already been delivered to six countries and 10 airbases. Lockheed Martin is currently working on the 10th low-rate initial production (LRIP) contract.
This “concurrency” has been a major criticism of the program, as now also is the recent revelation that further development under a program named continuous capability development and delivery (C2D2) will cost more than $11 billion during the next seven years. Lockheed Martin describes C2D2 as “phased capability improvements and modernization [to] the most survivable and connected aircraft ever built.” But C2D2 also includes some deferrals from the SDD program.
A key element of the C2D2 program is a further software upgrade designated Block 4. Aircraft are now being delivered with Block 3F software that was supposed to be definitive. However, in his latest report on the F-35 program, the Pentagon’s director of operational test and evaluation said that there are “many open deficiencies” in Block 3F.