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KC-135R Stratotanker

100 ARW, Mildenhall, Suffolk, United Kingdom

KC-135R Stratotanker
KC-135R Stratotanker
KC-135R Stratotanker MPRS Pod
KC-135R Stratotanker
KC-135R Stratotanker

The Boeing KC-135 Stratotanker was designed from the Boeing 367-80 model almost sixty years ago and was first rolled-out of Boeing's Renton plant on 20th July 1956, its first flight being completed on 31st August. Operational service commenced on 30th April 1957 with the 93rd Air Refuelling Squadron at Castle AFB in Merced, California. Designed to meet SAC's requirement for a tanker/transport aircraft, 820 Boeing C-135 variants were built over a ten-year production run, of which 749 KC-135s were built for the US Air Force as A & B models. 

KC-135R Stratotanker Cockpit
RAF Mildenhall Crest
351 ARS

Frontline Aviation has had the honour to work with the amazing men and women of the 100th Air Refuelling Wing (100ARW) on a few occasions. We've been fortunate to have experienced air to air refuelling missions first-hand whilst it provided much needed fuel for United States, NATO and non-NATO partner aircraft. This report explores the Wing's historic past, it's aircraft and current responsibilities and what the future may hold.

100th Air Refuelling Wing
United States Air Forces Europe
"The Bloody Hundredth"

100th Air Refuelling Wing

The 100ARW, also known as the "Bloody Hundredth", comprises the 100th Operations Group, with two squadrons; 100th Operation Support Squadron and 351st Air Refuelling Squadron.

The 100th Operations Support Squadron provides training, operational and expeditionary support to five U.S. Air Force major commands and NATO allies in the European/African theatres, including intelligence and adversary threat analysis, flight scheduling, mission planning, tactics, combat crew communications, weather, aircrew flight equipment, flight and jump records management, KC-135 simulator, survival training and data analysis.

Located at Royal Air Force Mildenhall in the United Kingdom, the 100ARW is the only U.S. tanker wing assigned to Europe and Africa refuelling U.S. and partner nation aircraft over a span of more than 20 million square miles using the KC-135 Stratotanker aircraft. The wing also provides critical bridge, aerial medivac and cargo transport capabilities enabling U.S. forces to deploy around the globe in a moment's notice.

The 351st Air Refuelling Squadron provides operational air refuelling, aero medical evacuation, airlift and rapid contingency response options for U.S. and NATO fighter, bomber, and support and reconnaissance aircraft in airspace overlying the Atlantic Ocean, Europe, Africa and Southwest Asia. Protects U.S. interests by employing 27 combat mission-ready KC-135 aircrews and 15 aircraft for contingency, defence operations planning / response, special operations and training missions from England and other forward operating locations.

The 100th Operations Group is responsible for planning, intelligence support, scheduling, and execution of USAFE’s air refuelling operations across Europe and Africa. The group's two squadrons (100th Operations Support Squadron and 351st Air Refuelling Squadron) operate and maintain 15 KC-135 Stratotanker aircraft, supporting operations in multi-service, allied and coalition receiver aircraft flying training, exercise, and contingency missions.

Bloody Hundredth
100 ARW

The History

The 100 ARW has an impressive history and its aircraft feature the famous 'Box D' tail insignia of the 100th Bombardment Group. It is in fact the only unit in the United States Air Force (USAF) authorized to display its historical World War II tail insignia.

Established on 1st June 1942, the 100th Bombardment Group (Heavy) was assigned to 3 Bomber Command as a 'paper' unit and remained unmanned until 27th October 1942 when a small number of men transferred from the 29th Bombardment Group to Gowen Field, Idaho, to serve as the initial cadre. Within four days the 100 BG moved to Walla Walla Army Air Base, Washington, where it received its first four aircrews and four Boeing B-17F Flying Fortress aircraft. The unit then moved to Wendover Field, Utah, on 30th November to begin operational training.

The first day of 1943 saw the unit move to Sioux City, Iowa, to assist in air and ground training for other groups bound for overseas deployment. Having received new B-17 aircraft the group departed the United States on 25th May 1943 and into the war in Europe, based at RAF Thorpe Abbots, Norfolk, where they remained throughout World War II.

On 25th June 1943, the 100 BG flew its first combat mission for  the Eighth Air Force against the submarine yards at Bremen, Germany -- the beginning of the Bloody Hundredth's legacy. The group inherited the Bloody Hundredth nickname from other bomb groups due to the amount of aircraft losses it sustained during the campaign. Although the 100 BG's losses were no more than any other units' at the war's end, the group experienced several instances where it lost 12 of 13 and 13 of 15 aircraft. For the next six months, the group focused its bombing attacks against German airfields, industrial targets and naval facilities in France and Germany. Just two months after entering the war, the group received its first Distinguished Unit Citation

(DUC) after attacking the German aircraft factory at Regensburg on 17th August, resulting in serious disruption to German fighter production.


During the period January to May 1944 the 100 BG bombed airfields, industrial targets, marshalling yards, and rocket sites in Western Europe and participated in the Allied campaign against German aircraft factories in March 1944 as well as a number of attacks on Berlin. For its March 1944 efforts, the 100 BG received its second DUC of the war. In June 1944 the 100 BG supported the Normandy invasion in France by bombing bridges and gun positions. The next month aircrews bombed enemy positions at St Lo, followed by similar campaigns at Brest in August and September. In October 1944 the 100 BG turned its attacks against enemy and ground defences on the Siegfried Line. After completing its Siegfried Line support, the group took on the task of attacking marshalling yards, occupied villages, and communication targets in the Ardennes during the Battle of the Bulge. For its extraordinary efforts in attacking heavily defended German installations in Germany and dropping supplies to the French Forces of the Interior from June through December 1944, the 100 BG received the French 'Croix de Guerre with Palm'. The 100 Bomb Group flew its last combat mission of World War II on 20th April 1945, having flown over 300 combat missions and suffering a staggering 177 aircraft losses.

In December 1945, the group returned to the United States, where it inactivated at Camp Kilmer, New Jersey, on 21st December 1945, reactivating again on 29th May 1947 at Miami Army Air Field as a reserve unit until it was again inactivated on 27th June 1949. After approximately five years, the 100th was activated as a medium bombardment wing on 1st January 1956 at Portsmouth AFB, New Hampshire, again assigned to the Eighth Air Force as part of Strategic Air Command.

For the next ten years the wing performed global strategic bombardment training, and global air refuelling with the Boeing B-47E Stratojet and the Boeing KC-97 Stratotanker.


Following a non-operational period  between April and June 1966, the unit was  re-designated as the 100th Strategic Reconnaissance Wing (SRW) and moved to Davis-Monthan AFB, Arizona. The wing absorbed the resources of the 4080th Strategic Wing and performed strategic reconnaissance with the Lockheed U-2 and BQM-34 Firebee drone aircraft. In mid-1976 the wing changed missions again when it transferred its drone operations to Tactical Air Command and its U-2s to the 9 SRW at Beale AFB, California.

After completing the transfer of its aircraft in September 1976, the Air Force re-designated the wing as the 100th Air Refuelling Wing (ARW) and relocated it to Beale AFB. Whilst at Beale, the 100 ARW assumed responsibility for providing worldwide air refuelling support to the 9 Strategic Reconnaissance Wing with the Boeing KC-135Q, until its inactivation on 15th March 1983. After an inactive status of over seven years it was again reactivated, this time as the 100th Air Division at Whiteman AFB, Missouri, on 1st July 1990. However, as has been the wing's past fate, the Air Force inactivated it once again on 1st August 1991.

Six months after its inactivation as an Air Division and over 46 years after departing England at the end of World War II, the Air Force reactivated the 100th ARW at RAF Mildenhall on 1st February 1992, with the 351st Air Refuelling Squadron (ARS) as its subordinate unit. From the time of its reactivation the 100 ARW has served as the United States Air Forces in Europe's only air refuelling wing and despite the age of its aircraft continues to provide an impeccable service with its fleet of KC-135R Stratotankers.

The Aircraft and Current Mission

Today's KC-135R model is a variant with new engines designed to give a much needed power boost, along with increased service life, better performance and fuel economy, together with reduced maintenance costs and compliance with modern day noise restrictions.

After assessment of various engines the General Electric/SNECMA CFM-56 was selected and the first KC-135R aircraft was rolled-out at Boeing's Witchita modification facility on 22nd June 1982, with the first unit (384th ARW at McConnell AFB) receiving its aircraft in June 1984. Numerous other modifications took place during the upgrade, including larger stabilisers, revised wing leading edges, wing and fuselage reinforcements, new yaw damper and rudder actuators and strengthened landing gear. Each CFM-56 engine provides an impressive increase in thrust of 22,000lb compared to the A-models original J-57 engines, which produced only 13,750lb each.

The normal crew on a KC-135R is made up of the pilot, co-pilot and boom-operator/loadmaster (who also doubles up as a radio operator if required). Each wing houses two primary fuel tanks, plus a reserve tank in each wing and a larger tank housed in the wing centre section. There are also nine fuel cells mounted under the cabin floor. The 'Boomer' operates the system from a pod under the rear fuselage, with access being gained through two openings in the floor at the rear of the fuselage. There are three 'beds' in the compartment, the centre one being used by the Boomer and the outer ones each side of the central one being used by instructors, students, or media.

The single high speed in-flight refuelling boom fitted to the KC-135's centreline is 27ft (8m) long, with an additional 18.5ft (5.6m) which can be extended or

retracted by the boom operator and can also be moved between 12.5 and 50 degrees in the vertical and 30 degrees left or right from the centre position. To guide receiver aircraft, the KC-135s are equipped with two rows of lights under the fuselage centreline, along with coloured markings on the boom itself, which indicate whether the receiver needs to move forward or backward and up or down so as to be in the correct position to receive fuel from the boom. Locking toggles within the receptacle keep the boom engaged with the receiving aircraft, with an auto-disconnect system that will release the boom if the receiver drops outside of the refuelling boom's envelope.

The 100ARW also has three pairs of Cobham/Flight Refuelling Ltd, Multi-Point Refuelling System (MPRS) pods (known as "Mippers") to allow for the aerial refuelling of NATO and US Navy/Marines Corps aircraft that use a hose and drogue refuelling method rather than the rigid boom system adopted by the US Air Force. The MPRS pods are attached to each wing-tip of the aircraft, one each side, these having a retractable 74ft (22.5m) hose.

A Boom-Drogue Adaptor (BDA) can also be attached to the end of the fixed boom to allow for aircraft using the hose and drogue method to refuel. The BDA is 9ft (2.74m) of hose attached to the telescoping part of the boom by a swivel coupling; the hose terminating in a non-collapsible drogue basket. The BDA looks somewhat ungainly as it dangles from the end of the

boom, but once in flight it becomes another valuable asset in the air-to-air refuelling scenario. The triple hose/drogue method makes it possible for two aircraft to be 'gassed' simultaneously on the two wing-tip drogues, but if the BDA on the rigid boom is in use then the wing-tip pods cannot be used due an inadequate refuelling envelope clearance between the receiver aircraft. The standard KC-135 orbit speed when refuelling is 275 knots indicated air speed (KIAS), or Mach 0.78. The maximum for the high-speed boom between sea level and 29,400ft is 355 to 373 KIAS, with the maximum speed when using the BDA is between 225 to 305 KIAS.

In 2009 the U.S Air Force selected Rockwell-Collins for the engineering, manufacturing and development phase of the C/KC-135 'Block 45' cockpit upgrade programme. The modernized KC-135 tanker's flight deck was fitted with the latest generation auto-pilot, flight director, radar altimeter and electronic engine instrument display. The programme was completed in July 2011.

The 100ARW regularly rotate aircraft Stateside for maintenance purposes, with newly arrived replacement airframes sporting the markings of the previous unit that operated the aircraft.

KC-135R Stratotanker Boom
F-15E Strike Eagle
F-15E Strike Eagle
F-35A Lightning II
F-35A Lightning II
F-35A Lightning II 495th Fighter Squadron

So what does the future hold for the 100th Air Refuelling Wing? The first flight of a fully-integrated, military-ready Boeing KC-46A 'Pegasus' tanker aircraft (based on Boeing's 767 commercial airliner) was scheduled for January 2015. The U.S Air Force plans to acquire 179 KC-46A tankers between 2015 and 2028, with earlier plans calling for a low rate initial production of seven aircraft in 2015, 12 aircraft in 2016 and then 15 per year between 2017 and 2027. Part of the tanker acquisition was a contract specification for the USAF to acquire 18 KC-46As by 2017. Today, despite some early teething problems in the fleet, the Air Force and Boeing officials have said that the programme is making good progress.

Frontline Aviation was informed that if the 100ARW ever acquire the new tanker they will likely be the last squadron to transfer. As the only aerial refuelling unit permanently based in Europe the KC-146 would appear to be a good replacement for the venerable Stratotanker. However, the future demand and needs of the USAF are always changing. The current political scene enforces the requirement for a permanent (and reliable) tanker fleet assigned to the European theatre and the KC-135R is fulfilling this role with honour.


The Wing is critical to support missions near and far, and close to hostile territory in certain situations. One thing is certain, whatever the future may hold for the 100ARW the "Bloody Hundredth" has a special place in history at RAF Mildenhall. Long may it remain. 

The Future of the 100ARW

F-22A Raptor

A selection of images taken by Frontline Aviation on recent air-to-air refuelling missions...

Our thanks go to the amazing members that make up the 100th Air Refuelling Wing, for whom without them this article would not have been possible. 

The Public Affairs Office team:

Jesenia E. Landaverde, SSgt 100 ARW public affairs media operations NCOIC

Capt. Tyler Whiting, 100 ARW PA Media Operations and Community engagement OIC

F-35A Lightning II

The illustrious crew of KC135R - 59-1511 "QUID 47":

Capt. Audrey Springer, 351st Air Refueling Squadron KC-135 Stratotanker Pilot

Lt. Col. Mark Watson, U.S. Air Force Europe-UK deputy chief of international relations division and KC-135 Stratotanker pilot

Airman 1st Class Max Richards, 351st Air Refueling Squadron boom operator

1st Lieutenant Nick Lopez, 351st ARS KC-135 co-pilot

100 ARW
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