What happened
On 15 October 2022, a KC-46A Pegasus, tail number 15-046069, was conducting routine air refueling operations over the North Atlantic Ocean when a mechanical failure occurred during a breakaway maneuver. The tanker, assigned to the 2d Air Refueling Squadron of the 305th Air Mobility Wing, was refueling an F-15E Strike Eagle, tail number 87-0192, from the 335th Fighter Squadron.
During the separation process, a nozzle binding event occurred within the Aerial Refueling Boom (ARB) system. This mechanical interference caused the boom to move rapidly upward with enough force to strike the tail cone of the KC-4ES. The incident resulted in an estimated government loss of approximately $8.3 million.
The investigation
The investigation examined the mechanical interaction between the two aircraft and the performance of the automated boom control systems. Investigators analyzed the flight data from the ARB's Air Refueling Control Computer (ARCC) and reviewed existing deficiency reports regarding the KC-46A's refueling hardware.
The board looked into the movements of both aircraft, specifically noting a power reduction by the tanker pilot and the high thrust settings required by the receiver aircraft due to known equipment stiffness. The investigation also evaluated why the automated boom control laws failed to mitigate the upward motion of the boom during the impact.