Two Major KC-46 Deficiencies Downgraded by Air Force

The Air Force has recently downgraded two category-1 deficiencies tied to the Boeing [BA] developed KC-46 next-generation tanker program to a category-2 designation, Defense Daily has learned.

Following a deficiency review board meeting Nov. 7, the service downgraded deficiencies related to the boom radial loads and the centerline drogue system to CAT-2 deficiencies, meaning a workaround solution had been established, according to a source close to the program.

A Boeing KC-46A tanker refuels an F-16. (Photo courtesy of Boeing)

A Boeing KC-46A tanker refuels an F-16. (Photo courtesy of Boeing)

During test flights, there were concerns that forces on the boom were approaching maximum load levels when the aircraft made contact with receiver aircraft. Further review and analysis enabled the downgrade, a Boeing spokesperson said in an emailed statement, adding, "Boeing will provide a software update in the future for enhanced operator feedback."

Issues with the centerline drogue system had it disconnecting from the receiver aircraft when it should not be doing so. Under certain conditions, the hose was not extending far enough to follow a moving receiver, with the resulting tension disconnecting the two aircraft. The issue occurred on multiple KC-46 aircraft with two separate F/A-18 Super Hornet receiver aircraft, according to the source.

Boeing said software updates have been implemented and successfully tested to eliminate disconnection during operational refueling.

"This is a positive step forward for the program and we remain confident in the unmatched capabilities of the KC-46 tanker aircraft and its refueling system," the company said. "To date we have completed more than 3,700 flight hours and delivered more than 4 million pounds of fuel to receiver aircraft."

Air Force Spokeswoman Ann Stefanek confirmed in a Friday email that the two CAT1 deficiencies involving the centerline drogue system and feedback to the operator on inputs to the boom were downgraded to category-2 on Nov. 7. 

Three category-1 deficiency reports remain in the KC-46 program; two on the Remote Vision System and one on the stiffness of the boom, she said, adding, "Boeing and the Program Office are assessing the risk and potential solutions for the remaining deficiencies."

Last Thursday, Air Force Secretary Heather Wilson said the service was working together with Boeing to resolve the remaining deficiencies and issues with the KC-46 program, which has undergone multiple schedule delays and cost overruns. A target delivery date of Oct. 27 has come and gone, and Wilson dodged a question about whether the Air Force still anticipates a 2018 delivery, saying "We will work through with Boeing to get the equipment that works" (Defense Daily, Nov. 15). She added that the Air Force was in a meeting with Boeing that same day to work through "a couple major deficiencies."

The Air Force is not required to wait until the deficiencies are resolved to begin accepting deliveries. However, both the service and Boeing have been operating with the assumption that all category-1 issues are resolved or downgraded before aircraft are put on the ramp, according to Defense News, which first reported that the Air Force had found two additional category-1 deficiencies this past September.

Boeing is still working toward the goal of initial KC-46 deliveries beginning before the end of the year, a spokesperson said.

This story has been updated with a statement from the Air Force.

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