Six crew members were killed in a refueling plane crash in western Iraq on Wednesday night. The aircraft was a Boeing KC-135 Stratotanker, and United States Central Command said the crash happened after an “unspecified incident involving two aircraft in friendly airspace.”Central Command also said the crash was not caused by hostile or friendly fire. The second plane involved in the incident landed safely.The United States Department of Defense has not confirmed the identities of the six people killed. However, Ohio Governor Mike DeWine posted on social media that three of the victims were members of the Ohio National Guard. Tommy Tuberville, an Alabama Senator, also posted on Facebook saying another service member killed in the crash was from Alabama.Staff at the Aviation Museum of New Hampshire say the KC-135 model has been in service since the 1950s.“It’s still actively being flown by the Air Force, the Air National Guard, and the Air Force Reserves,” museum volunteer Bill MacMillan said.While in flight, the KC-135 and its updated model, the Boeing KC-46A Pegasus, extend a refueling boom that transfers fuel to other aircraft.“The air refueler actually flies that boom to a fine-tuned location right to the refueling port of the smaller aircraft,” museum volunteer Chuck Poltack said. “The fighter jet peels off, and the next one comes in.”Poltack added that the pilots and refueling crews undergo extensive training.“For them it’s standard procedure. They’re experienced and they train for that.”While mid-air refueling is a common practice, investigators are now focused on determining what happened in Iraq.The cause of the crash has not been determined by the Pentagon. The aircraft was on a support mission in operations against Iran. The six casualties bring the U.S. death toll in Operation Epic Fury to 13.

LONDONDERRY, N.H. —

Six crew members were killed in a refueling plane crash in western Iraq on Wednesday night. The aircraft was a Boeing KC-135 Stratotanker, and United States Central Command said the crash happened after an “unspecified incident involving two aircraft in friendly airspace.”

Central Command also said the crash was not caused by hostile or friendly fire. The second plane involved in the incident landed safely.

The United States Department of Defense has not confirmed the identities of the six people killed. However, Ohio Governor Mike DeWine posted on social media that three of the victims were members of the Ohio National Guard. Tommy Tuberville, an Alabama Senator, also posted on Facebook saying another service member killed in the crash was from Alabama.

Staff at the Aviation Museum of New Hampshire say the KC-135 model has been in service since the 1950s.

“It’s still actively being flown by the Air Force, the Air National Guard, and the Air Force Reserves,” museum volunteer Bill MacMillan said.

While in flight, the KC-135 and its updated model, the Boeing KC-46A Pegasus, extend a refueling boom that transfers fuel to other aircraft.

“The air refueler actually flies that boom to a fine-tuned location right to the refueling port of the smaller aircraft,” museum volunteer Chuck Poltack said. “The fighter jet peels off, and the next one comes in.”

Poltack added that the pilots and refueling crews undergo extensive training.

“For them it’s standard procedure. They’re experienced and they train for that.”

While mid-air refueling is a common practice, investigators are now focused on determining what happened in Iraq.

The cause of the crash has not been determined by the Pentagon. The aircraft was on a support mission in operations against Iran. The six casualties bring the U.S. death toll in Operation Epic Fury to 13.