SCOTT AIR FORCE BASE, Ill. – Air Mobility Command officials released the accident investigation board report regarding a Nov. 1, 2016, incident in which an aerial refueling boom detached from a KC-10 extender aerial refueling tanker during a training flight over Idaho.
The aircraft and crew were operating out of Travis Air Force Base, California, where all are assigned. The crew was on a training mission and planned to refuel F-15 Eagle fighters and a C-17 Globemaster III mobility aircraft when the incident occurred.
In preparation for aerial refueling, the boom operator lowered the boom, the part of a tanker aircraft that connects to the receiving aircraft when delivering fuel. The boom immediately began to move erratically and well outside of its operational and structural limits. The boom operator was not able to control the boom and the aircraft commander declared an in-flight emergency. The aircrew was preparing to land at Mountain Home Air Force Base, Idaho, when the boom fully detached from the fuselage and landed in an empty field below. The aircrew subsequently landed without further incident at Mountain Home. There were no injuries or fatalities resulting from this mishap. The monetary value of loss to the government was $6.52 million.
The accident investigation board identified two causes and one contributing factor to the incident. The first cause was a sheared Dual Rotary Voltage Transducer (DRVT) rotary crank that resulted from DRVT rotary bearing misalignment. The second cause, related to the first, was the boom operator’s failure to turn off the boom flight control switch in a timely manner. Turning off this switch would have prevented the erratic movements that resulted in the boom departing the aircraft. In addition, the AIB found that the failure of maintenance personnel to comply with technical orders prevented the possible detection of an erratic DRVT, significantly contributing to the mishap.
The accident investigation board president for this incident is Col. Perry Long III, 375th Operations Group commander, Scott Air Force Base, Illinois. Colonel Long was appointed president of the board by Maj. Gen. Thomas Sharpy, Air Mobility Command vice commander. Accident investigations are intended to identify all circumstances surrounding an incident, provide an opinion based on preponderance of evidence as to the cause or causes of the mishap, and prepare a publicly releasable report on the matter.
The report will be available here on July 19.