Boeing KC-135 Stratotanker

ICAO type code: K35R · Boeing · military aerial refueling tanker

KC-135 at a glance

First flight

1956

Length

136 ft 3 in (41.5 m)

Wingspan

130 ft 10 in (39.9 m)

Engines

4 × CFM International F108 (CFM56) turbofans

Crew / capacity

Crew of 3; ~200,000 lb fuel capacity

Cruise speed

~460 kt (529 mph)

Service ceiling

50,000 ft

Range

~1,300 nmi with heavy fuel offload

How to recognize the KC-135

The KC-135 looks like an early jet airliner painted gray, with a refueling boom hanging under its tail.

• Engines: four high-bypass turbofans in pods under the wing, larger than the original engines from the 1950s.
• Wing: low, sharply swept, with no winglets.
• Boom: a long refueling boom under the rear fuselage, with small control wings near its tip.
• Tail: a tall fin with a long dorsal fin and conventional low tail.
• Fuselage: slim with few windows, and a pointed nose.
• Color: usually gray.
• Refueling: you may see it flying in a racetrack pattern at high altitude while other jets line up behind it.

The C-17 has a high wing and T-tail. A 757 has two engines and no boom.

The KC-135's fuselage is slimmer than a 707's, and its long, narrow body has only a handful of small windows. Its CFM56 turbofans replaced the original smoky turbojets and are much fatter than the 1950s engines. The boom operator lies prone in a compartment under the tail, looking through a window to steer the boom. At night, receiver aircraft follow guidance lights on the tanker's belly, and the boom itself may be lit.

Where and when you'll see it

The Air Force, Air National Guard and Air Force Reserve fly KC-135s from bases including McConnell (Kansas), Fairchild (Washington) and MacDill (Tampa), and Guard units in cities such as Milwaukee, Pittsburgh, Birmingham, Salt Lake City, Phoenix and Columbus. They refuel fighters, bombers and transports over training areas and on long missions.

Refueling tracks are usually at FL200 to FL300. On ADS-B the type code is K35R; callsigns vary from word-and-number mission callsigns to REACH on airlift-style trips. Some fly with ADS-B off.

Tankers often fly refueling missions over remote areas, such as the Gulf of Mexico, the Great Lakes or the Western deserts, and they may orbit for hours. You may also see them flying practice approaches at their home bases, or heading overseas on deployments.

Easily confused with

• Boeing C-17 Globemaster III: The C-17 has a high wing, a T-tail and winglets.
• Boeing 757-200: The 757 has two engines and no refueling boom.

Quick facts

• Boeing's internal model number for the KC-135 was 717, a number later reused for the airliner that became the Boeing 717.
• More than 700 KC-135s were built between the 1950s and 1965, and many are now more than 60 years old.
• The KC-135 shares an ancestor with the Boeing 707 but has a narrower fuselage.

KC-135 questions

Cities where it's a regular

Phoenix · Riverside · Detroit · Tampa · St. Louis · Sacramento · Pittsburgh · Milwaukee · Oklahoma City · Salt Lake City · Birmingham · Buffalo · Tucson · Honolulu

Spot one live

Open the live sky tool and look for K35R in the type column, or browse the live map on airplanes.live.