Boeing KC-135 Stratotanker

KC-135 Stratotanker

In operation since 1957, the KC-135 Stratotanker is used primarily to re-fuel aircraft during flight. Modified KC-135s, however, serve as flying command posts, pure transport, electronic reconnaissance, and photo mapping craft.

Tanker Characteristics

The KC-135 possesses the following characteristics:

  • Flying boom to provide fuel transfer
  • Drogue to re-fuel probe-equipped aircraft (attached to the boom)
  • Passenger and cargo deck located above the fuselage-mounted tanks

KC-135 Skin-Replacement

During a 13-year period ending in 1988, Boeing replaced the lower wing surfaces with an improved aluminum-alloy skin. The program included the following tasks:

  • Skin replacement on 746 aircraft (1500 square feet per aircraft)
  • Replacement of the engine strut fittings
  • Installation of 564 parts, 32,200 steel fasteners, and 19,500 aluminum rivets

CFM Engine-Replacement

To increase takeoff and carrying capacity, improve fuel efficiency, and reduce engine noise and pollution levels, Boeing replaced the original KC-135A engines with CFM56 engines for the U.S. Air Force. The serviced aircraft were re-designated as KC-135Rs, and the engine-replacement program achieved the following results:

  • Reduced fuel consumption 27%, saving 2.3 to 3.2 million barrels of fuel annually
  • Reduced decibel levels from 126 to 99 decibels (98%) while reducing the noise-impact area near airports from 240 to 3 square miles

JT3D Engine-Replacement

The Air Force Reserve and Air National Guard retained Boeing to replace KC-135-A engines with refurbished JT3D engines taken from used commercial 707 airliners. The aircraft designation changed to KC-135E, and the program achieved the following results:

  • Increased engine power 30%
  • Reduced noise levels 85%
  • Replaced/refurbished struts and cowling, brakes, cockpit controls, and instruments

Continuing Improvements

The U.S. Air Force retained Boeing to provide the following improvements: add wingtip, hose, and drogue refueling pods; modernize the cockpit; provide new compasses and radar systems; and install a global positioning system (GPS).