Here’s something you don’t see every day: the KC-46A tanker program is projected tounderrun its $51.7 billion cost estimate by about $300 million. However, the test and development schedule remain ambitious, according to a Government Accountability Officereport released Thursday, The program acquisition unit cost will be $287 million per jet; or $1.8 million apiece less than estimated, states the report. All that said, GAO noted that the director of operational test has warned that delays in training aircrew and maintainers could slip testing as much as six-to-12 months. Even so, GAO conceded that “the program has not missed any major milestones” and that production of all four test articles is well underway. “The next 12 months will be challenging,” GAO said, because flight testing and software development must be finished, but “overall, the development of about 15.8 million lines of software code is progressing mostly according to plan.” It should be noted, though, that the cost numbers are for the contract; Boeing underbid the work and expects to eat about $200 million on the KC-46, which it has said it will make up with higher volume aircraft and parts sales and other efficiencies, ultimately turning a profit.