KC-135 Stratotanker: The Flying Gas Station For US Military Planes

An American aerial refuelling aircraft crashed in western Iraq on Thursday. The Boeing KC-135 Stratotanker was shot down by a missile fired by “resistance groups,” Iran's state media said. US officials denied that the aircraft was brought down by hostile fire.

A spokesperson for Iran's Central Headquarters of the Holy Prophet said all six crew on board were killed. Iran's Islamic Revolution Guard Corps (IRGC) also said the Boeing KC-135 Stratotanker was targeted by air defence systems of the “Resistance Front” while it was refuelling a fighter jet.

The Islamic Resistance in Iraq, an umbrella group of Iran-backed armed factions, claimed responsibility for the attack. The group said it shot down the aircraft “in defence of our country's sovereignty and airspace,” Reuters reported.

The KC-135 crash is the fourth American military aircraft lost during the US-Israeli war on Iran. Earlier, three F-15 fighter jets were lost due to friendly fire over Kuwait, US officials said.

What is the KC-135 Stratotanker?

The KC-135 Stratotanker is a military aircraft used mainly for aerial refuelling, meaning transferring fuel to other aircraft mid-air. It has been a part of the US Air Force's operations for more than 60 years.

The aircraft allows fighter jets, bombers and other military planes to stay in the air longer and travel greater distances. It also supports aircraft from the US Navy, Marine Corps and allied countries.

The KC-135 is based on Boeing's 367-80 design, which also led to the development of the commercial Boeing 707 passenger aircraft.

Hundreds of KC-135 aircraft remain in service with the US Air Force, Air National Guard and Air Force Reserve.

Main Role and Missions

Apart from refuelling aircraft mid-air, KC-135 can also carry passengers and cargo, support aeromedical evacuation missions and transport injured or ill patients using specialised medical pallets.

During medical evacuation flights, a medical team consisting of flight nurses and technicians can be added to the crew.

Design and Features

The KC-135 is powered by four turbofan engines mounted under swept wings. These engines allow the aircraft to take off with a maximum weight of about 1.46 lakh kg.

The aircraft has a cargo deck above the refuelling system, allowing it to carry both passengers and equipment.

Depending on the configuration, it can transport around 37,600 kg of cargo or several dozen passengers.

Most of the aircraft's internal fuel can be transferred to other aircraft during mid-air refuelling missions, which is its primary role.

How the Aircraft Refuels Others

The KC-135 transfers fuel using a flying boom, a long tube that extends from the rear of the aircraft and connects to another aircraft during flight. A crew, ‘boom operator', sits at the back and controls the boom during refuelling.

The aircraft can also use a drogue system, a hose with a basket-shaped attachment, to refuel aircraft fitted with probes.

Some KC-135 aircraft are equipped with a multipoint refuelling system with pods on the wingtips, which allows them to refuel two aircraft at the same time.

History

The US Air Force first ordered the aircraft in 1954, purchasing the first 29 planes of what would become a fleet of 732 aircraft.

The first KC-135 flew in August 1956, and the first production aircraft was delivered in June 1957. The final aircraft was delivered to the Air Force in 1965.

Variants

Many original KC-135 aircraft were later fitted with CFM-56 engines. These upgraded versions are known as KC-135R or KC-135T. These upgraded aircraft,

• Can offload 50 per cent more fuel.
• Are 25 per cent more fuel-efficient.
• Cost 25 per cent less to operate.
• Are much quieter.

Another variant, the KC-135E, used different engines and remained in service until 2009, when the final aircraft was retired.