KC-46 schedule unlikely to go as planned

Based on the tanker replacement programme’s history, its current schedule is “aggressive and unlikely to be executed as planned,” Michael Gilmore wrote in his annual report. In a prime example of schedule delay, the US Air Force had planned to complete 66% of testing by the end of the engineering, manufacturing and development phase. By the beginning of low-rate production last August though, Boeing had completed only 30% of EMD testing, the report states.
When Gilmore’s office approved a test and evaluation master plan in November 2016 that would support KC-46’s entrance into low-rate production that August, it did so with lingering concerns about leaving enough time to correct discrepancies between the end of developmental testing and the beginning of initial operational test and evaluation, he writes.
“Execution of the current schedule assumes historically unrealistic test aircraft fly and re-fly rates,” Gilmore writes.
Though the programme is on track to become an effective aerial refueling platform, several capabilities still require correcting or additional testing. During testing last January, Boeing discovered higher than expected axial loads on the tanker’s refueling boom. That pushed Boeing’s scheduled low-rate initial production decision from June to August while Boeing redesigned the boom control system.
Boeing implemented a hardware-based solution for the refueling issue, which involved inserting two bypass valves in the fly-by-wire-controlled boom to relieve the aerodynamic pressure. However, the current boom represent a prototype rather than a production-ready design.
Last year, the KC-46 successfully refueled a USAF A-10, allowing the programme to move ahead toward initial production. Boeing also demonstrated aerial refueling with the the US Navy’s F/A-18 and AV-8B using the centreline and wing drogue systems and the KC-46 as a receiver aircraft. The company also completed refueling demonstrations on the C-17 airlifter and F-16 using the aerial refueling boom. But Gilmore notes Boeing has only performed daylight refueling operations and none of the aircraft have been certified as receiving platforms.
flightglobal