The US military says a KC-135 refueling plane supporting operations against Iran has crashed in western Iraq, killing four of its six crew members.
US Central Command, which oversees the Middle East, said the crash followed an unspecified incident involving two planes in “friendly territory,” and that the other plane landed safely.
Here is what is known so far about the tanker, which is the fourth publicly acknowledged US plane crash during the war with Iran:
The KC-135, a long-range tanker aircraft
The KC-135 Stratotanker is a US Air Force aircraft used to refuel other aircraft in the air, allowing them to travel long distances and sustain operations for long periods of time without landing. The plane is also used to transport injured personnel during medical evacuation or to conduct surveillance operations, according to military experts.
Based on the same design as the Boeing 707 passenger plane, the tank has been in service for more than 60 years, supporting the US Air Force, Navy and Marine Corps and allied aircraft, according to an Air Force statement. The aging aircraft is expected to be phased out as more of the next-generation KC-46A Pegasus fleet enters service.
Despite improvements over the years, the age of the KC-135s has created concerns about their reliability and durability.
“The last of these planes were produced in the 1960s,” said Yang Uk, a security expert at South Korea’s Asan Institute for Policy Studies. He added that the transition to the KC-46A went slower than expected.
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According to the Congressional Research Service, the Air Force last year had 376 KC-135s, including 151 active, 163 in the Air National Guard and 62 in the Air Force Reserve.
The basic crew of the KC-135 consists of three people: the pilot, the pilot and the boom operator. Nurses and medical technicians are added to aeromedical evacuation duties.
Refueling usually takes place at the rear of the aircraft, where the boom operator is located. The fuel boom is lowered to engage fighters, bombers or other aircraft. In most aircraft, the boom operator works lying face down looking out the window below the aircraft.
Some KC-135s can refuel aircraft from pods on their wings. Tanks have room to carry cargo or passengers if needed.
Refueling tanks could play a more important role if the war with Iran continues, as US planes may need to fly long missions to track Iranian forces retreating deeper into the country, Yang said.
The cause is not immediately known
US Central Command said four of the six crew members aboard the KC-135 were confirmed dead and that rescue efforts were ongoing. It said the circumstances of the crash were still under investigation but the loss of the plane “was not caused by hostile or friendly fire.”
An American official, who also did not want to be named to discuss the ongoing situation, said the other plane involved was a KC-135. Yechiel Leiter, Israel’s ambassador to the US, wrote to X that another plane landed safely in Israel.
Yang said it would be rare for a refueling tank to be hit by enemy fire because such operations are usually carried out behind combat zones.
The crash occurred after three US F-15E fighter jets were accidentally shot down last week by friendly fire from Kuwait.
KC-135s have been involved in several fatal accidents. The most recent occurred on May 3, 2013, when a KC-135R crashed after takeoff south of Chaldovar, Kyrgyzstan, while supporting the war in Afghanistan.
In that crash, the crew had problems with the plane’s rudder, according to a US Air Force investigation. While trying to stabilize the plane, the tail section broke off and the plane exploded, killing all three crew members.
The worst air-to-air collision involving an airplane occurred in 1966, when a B-52 bomber carrying nuclear bombs crashed into a tanker near Palomares, Spain.
The accident caused the truck to crash, killing the four people on board. The disaster led to a major decontamination effort to clean up the nuclear material that was scattered when the conventional explosives in hydrogen bombs exploded after hitting the ground.
© 2026 The Canadian Press
