program baseline was finalized in March 2012, and since that time costs have remained relatively stable. Table 1 notes the significant cost, quantity, and schedule changes from the original program baseline and the relative stability since the new baseline was established. At the time the new F-35 acquisition program baseline was finalized, it did not identify new initial operational capability (IOC) dates for the three military services. The following year DOD issued a memorandum noting that Marine Corps and Air Force were planning to field initial operational capabilities in 2015 and 2016, respectively, and that the Navy planned to field its initial capability in 2018. The memorandum emphasized that the Marine Corps and Air Force initial operational capabilities would be achieved with aircraft that possess initial combat capabilities, and noted that those aircraft would need additional lethality and survivability enhancements to meet the full spectrum of warfighter requirements in the future. These new parameters represented a delay of 5 to 6 years from the program’s initial 2001 baseline and a reduction in the capabilities expected at IOC. In March 2005 we recommended that DOD implement an evolutionary, incremental approach to developing and fielding the F-35—then known as the Joint Strike Fighter—to ensure that the warfighters would receive an initial combat capability that, at a minimum, would meet their most immediate needs. Again in March 2010, we recommended that DOD identify the absolute minimum combat capabilities that would be acceptable by each of the military services to field their initial operational capabilities and establish reasonable, realistic timeframes for achieving those requirements. In both instances, we noted that the military services should consider trading off desired capabilities in order to more rapidly field aircraft with an initial set of useable capabilities and that any capabilities not needed to meet immediate warfighting needs should be deferred to a future development increment. In both instances, DOD agreed with the intent of our recommendation, but believed that its existing program management practices were sufficient. Delays in the testing of critical mission systems software have put the delivery of expected warfighting capabilities to the Marine Corps at risk, and could affect the delivery of capabilities to the Air Force and Navy as well. F-35 developmental flight testing is separated into two key areas: mission systems and flight sciences. Mission systems testing is done to verify that the software and systems that provide critical warfighting capabilities function properly and meet requirements, while flight science testing is done to verify the aircraft’s basic flying capabilities. In a March 2013 report we found that development and testing of mission systems software was behind schedule, due largely to delayed software deliveries, limited capability in the software when delivered, and the need to fix problems and retest multiple software versions. These same challenges continued thorough 2013, and as a result progress in mission systems testing has been limited. The Director of Operational Test and Evaluation (DOT&E) predicts that the delivery of expected warfighting capabilities to the Marine Corps could be delayed by as much as 13 months. Delays of this magnitude could also increase the already significant concurrency between testing and aircraft procurement and result in additional cost growth. Although mission systems testing is behind, the F-35 program has been able to accomplish nearly all of its planned flight science testing. The program also continued to make progress in addressing key technical risks, although some of that progress has been limited. While the F-35 program was able to accomplish all of the mission system test flights it had planned in 2013, it did not accomplish all of the planned falling short by 11 percent. The F-35 program planned to fly test points,329 mission systems test flights and accomplish 2,817 test points in 2013. The program actually flew 352 test flights, exceeding the goal, but only accomplished 2,518 test points. According to program and contractor officials, slow progress in developing, delivering, and testing mission systems software continues to be the program’s most significant risk area. The F-35 program is developing and fielding mission systems software capabilities in blocks: (1) Block 1, (2) Block 2A, (3) Block 2B, (4) Block 3i, and (5) Block 3F. Each subsequent block builds on the capabilities provided in the preceding blocks. Blocks 1 and 2A provide training capabilities and are essentially complete, with some final development and testing still underway. Blocks 2B and 3i provide initial warfighting capabilities and are needed by the Marine Corps and Air Force, respectively, to achieve initial operational capability. Block 3F is expected to provide the full suite of warfighting capabilities, and is the block the Navy expects to have to achieve its initial operational capability. Developmental testing of Block 2B software is behind schedule and will likely delay the delivery of expected warfighting capabilities. The delivery of this software capability is of high near-term importance because it provides initial warfighting capability for the overall F-35 program, and is needed by the Marine Corps to field its initial operational capability in July 2015. As of January 2014, the program planned to have verified the functionality of 27 percent of the software’s capability on-board the aircraft, but had only been able to verify 13 percent. This leaves a significant amount of work to be done before October 2014, which is when the program expects to complete developmental flight testing of this software block. According to DOT&E, Block 2B developmental testing will not be completed as scheduled and could be delayed by as much as 13 months, as the program has had to devote time and resources to address problems and completing development of prior software blocks. Delays of this magnitude would mean that the Marine Corps will not likely have all of the capabilities it expects in July 2015, its planned initial operational capability date. At this time it is not clear exactly which of the expected capabilities will be available as testing is still ongoing. The effects of these delays compound as they also put the timely delivery of Air Force and Navy initial operational capabilities at risk. The Air Force expects to field its initial operational capability in August 2016 with Block 3i aircraft that possess the same warfighting capabilities as the Marine Corps aircraft, but have upgraded computer hardware. The Navy plans to achieve its initial operational capability in August 2018 with Block 3F aircraft that possess the full suite of F-35 warfighting capabilities. Program and contractor officials have stated that while they recognize that the program faces software risks, they still expect to deliver all of the planned F-35 software capabilities to the military services as currently scheduled. However, given the uncertainty in mission systems software testing and the significance of the F-35 to future force structure plans, it is important that the military services have a clear understanding of the specific capabilities that they can realistically expect to receive, and those capabilities that are not likely to be delivered by their initial operational capability dates—the first of which is scheduled for July 2015. In addition, because the F-35 is DOD’s most costly and ambitious acquisition program, it is important that DOD keep Congress informed about the status of the program. Without a clear understanding of the specific capabilities that will initially be delivered, Congress and the military services may not be able to make fully informed resource allocation decisions. Delays in mission systems software testing could also increase costs. As currently planned, DOD expects to complete developmental flight testing in 2017. If the flight test schedule is extended, the program may have to retain testing and engineering personnel longer than currently expected, which would increase development cost. DOD currently expects to have invested $70.2 billion to procure 359 aircraft by 2017 when developmental flight testing is scheduled to end. Our past reports have concluded that purchasing aircraft while concurrently conducting developmental flight testing increases the risk that problems will be discovered late in testing and additional funding will be needed to rework aircraft that have already been purchased. If F-35 procurement plans remain unchanged and developmental testing continues into 2018, the cost risks associated with concurrency will likely increase as DOD expects to have invested $83.4 billion in 459 aircraft by that point in time. The F-35 contractor recognizes that additional testing efficiencies are important in order to deliver capabilities on schedule and cost. One way it plans to gain efficiency is to use test results from one F-35 variant to close out test points for the other two variants in instances in which the variants have common functions. According to test officials, most mission systems testing can be accomplished on any variant and only a limited amount of variant-specific testing is required. Contractor officials pointed out that this type of efficiency would help mitigate some testing risk, but they also recognized that it will still be difficult to make up the lost time in the test program. They noted that delays in specific test events generally impact the entire test schedule because the ability to conduct future testing is often dependent on the completion of the earlier events. The program accomplished nearly all of the flight sciences testing, including weapons testing, it had planned for 2013. As of December 2013, the program had achieved half of the total number of test points required to complete all flight science testing for the program. Figure 1 below shows the number of flight science test points planned and accomplished for each F-35 variant as of December 2013, and also identifies the total number of test points required for each variant to complete flight science testing. The program made progress despite the fact that flight testing was halted twice at the beginning of the year to investigate and fix cracks in an engine fan blade and leaky fuel hoses. In addition, program and contractor officials emphasized that employee furloughs that occurred in 2013, due to mandatory sequestration, limited the amount of flight testing that could be done during that time as well.science and weapons testing accomplishments included: Some of the key flight Conventional takeoff and landing variant – The program successfully demonstrated the variant’s ability to launch AIM-120 missiles from its internal weapons bay and to refuel while in flight. The program also continued testing the aircraft’s ability to function at high vertical flight angles, although program officials noted that the testing took longer than expected.