Boom trouble has delayed KC-46 tanker refueling trials, reported Flightglobal. A turbulent “bow wave effect” generated when connecting with the C-17 created “higher-than-expected boom axial loads” and prevented the system from passing fuel, according to the April 4 article. Additional planned boom testing with the C-17 and the A-10 is on hold until a fix is found. “We are working to resolve the issue and will have a better understanding of any program impact shortly,” Boeing spokesman Charles Ramey said Tuesday in an e-mail to Air Force Magazine. “It’s important to remember that this is a developmental program where issues are discovered and fixed. While we’re working the issue, we continue to conduct other required flight testing.” He noted the program’s first 767-2C aircraft just recently completed its 100th flight. The Pegasus tanker first successfully refueled an aircraft, the F-16C, using the boom delivery system in January and has successfully refueled a Marine Corps AV-8B Harrier II and a Navy F/A-18C using using its hose and drogue system. Air Force Vice Chief of Staff Gen. David Goldfein told members of the Senate Armed Services Subcommittee on Readiness and Management Support in March there had been recent issues with boom axial loads, but a possible software fix was expected to ward off delays. (See also Tanker Time is Tight from the February issue of Air Force Magazine.)
The Air Force and Boeing agreed to a nearly $2.4 billion contract for a new lot of KC-46 aerial tankers on Nov. 21. The deal, announced by the Pentagon, is for 15 new aircraft in Lot 11 at a cost of $2.389 billion—some $159 million per tail.