Aerial refueling 1

Aerial refueling

A C-17 Globemaster refuels through the boom ofa KC-135 Stratotanker

Boom and receptacle: USAF KC-135RStratotanker, two F-15s (twin fins) and two

F-16s, on an aerial refueling training mission

Probe and drogue: USAF HC-130P HIFRs aHH-60 Pave Hawk

Aerial refueling, also called air refueling, in-flight refueling (IFR),air-to-air refueling (AAR) or tanking, is the process of transferringfuel from one aircraft (the tanker) to another (the receiver) duringflight. [1] Applied to helicopters, it is known as HAR for HelicopterAerial Refueling.

The procedure allows the receiving (generally military) aircraft toremain airborne longer, extending its range and therefore those of itsweapons or its deployment radius. A series of air refuelings can giverange limited only by crew fatigue and engineering factors such asengine oil consumption. Because the receiver aircraft can be topped upwith extra fuel in the air, air refueling can allow a take-off with agreater payload which could be weapons, cargo or personnel: themaximum take-off weight is maintained by carrying less fuel andtopping up once airborne. Alternatively, a shorter take-off roll can beachieved because take-off can be at a lighter weight before refuelingonce airborne.

The two main refueling systems are probe and drogue, which issimpler to adapt to existing aircraft, and the flying boom, which offersgreater fuel transfer capacity, but requires a dedicated operator stationand specially designed receiving receptacle.Usually, the aircraft providing the fuel is specially designed for thetask, although refueling pods can be fitted to existing aircraft designs ifthe "probe and drogue" system is to be used (see later). The cost of therefueling equipment on both tanker and receiver aircraft and thespecialized aircraft handling of the aircraft to be refueled (very close"line astern" formation flying) has resulted in the activity only beingused in military operations. There is no known regular civilian in-flightrefueling activity. Originally employed to extend the range ofintercontinental strategic bombers, air refueling since the Vietnam Warhas been extensively used in large-scale military operations for manydifferent aircraft and helicopters. For instance, in the Gulf War and theIraqi invasion of Kuwait and the Iraq War, all coalition air sorties wereair-refueled except for a few short-range ground attack sorties in the Kuwait area.

History and development

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Pioneer experiments

Capt. Lowell H. Smith and Lt. John P. Richterreceiving the first mid-air refueling on June 27,1923, from a plane flown by 1st Lt. Virgil Hine

and 1st Lt. Frank W. Seifert

Some of the earliest experiments in aerial refueling took place in the1920s; two slow-flying aircraft flew in formation, with a hose rundown from a hand-held fuel tank on one aircraft and placed into theusual fuel filler of the other. The first mid-air refueling between twoplanes occurred on June 27, 1923, between two Airco DH-4B biplanesof the United States Army Air Service. An endurance record was set bythree DH-4Bs (a receiver and two tankers) on August 27–28, 1923, inwhich the receiver airplane remained aloft for more than 37 hoursusing nine mid-air refuelings to transfer 687 gallons of aviationgasoline and 38 gallons of engine oil. The same crews demonstratedthe utility of the technique on October 25, 1923, when a DH-4 flewfrom Sumas, Washington, on the Canadian border to Tijuana, Mexico,landing in San Diego, using mid-air refuelings at Eugene, Oregon, andSacramento, California.

In 1929, a group of U. S. Army Air Corps fliers, led by then Major Carl Spaatz, set an endurance record of over 150hours with the Question Mark over Los Angeles. Between June 11 and July 4, 1930, the brothers John, Kenneth,Albert, and Walter Hunter set a new record of 553 hours 40 minutes over Chicago using two Stinson SM-1Detroiters as refueler and receiver. Aerial refueling remained a very dangerous process until 1935 when brothersFred and Al Key demonstrated a spill-free refueling nozzle, designed by A. D. Hunter.[2] They exceeded the Hunters'record by nearly 100 hours in a Curtiss Robin monoplane [3], staying aloft for more than 27 days.[4]

A F-101A Voodoo (top right), B-66 Destroyer(top left) and F-100D Super Sabre refuel from a

KB-50J tanker in the early 1960s.

There were parallel experiments conducted in Europe; at Le Bourgetthe Aéro-Club de France and the 34th Aviation Regiment of the FrenchAir Force were able to demonstrate passing fuel between machines atthe annual aviation fete at Vincennes in 1928.[5] The UK's RoyalAircraft Establishment was also trialling refuelling-in-mid-air, with theaim to use this technique to extend the range of the long-distanceflying boats that serviced the British Empire. By 1931 they haddemonstrated refueling between two Vickers Virginias, with fuel flowcontrolled by an automatic valve on the hose which would cut off ifcontact was lost.[6] The aviation pioneer Alan Cobham bought a patentfrom David Nicolson and John Lord for £480 each and then developedthe probe and drogue method and gave public demonstrations of the

system. In 1934 he founded Flight Refuelling Ltd. (FRL), and by 1938 had used an automatic system to refuelaircraft as large as the Short Empire flying boat Cambria from an Armstrong Whitworth AW.23.[4] Handley PageHarrows were used to refuel the Empire flying boats for regular transatlantic crossings. During the closing months ofWorld War II it had been intended that Tiger Force's Lancaster and Lincoln bombers would be flight refueled inoperations against the Japanese homelands, but the war ended before the aircraft could be deployed. FRL's post-wartrials used a Lancaster tanker trailing the hose and drogue from an HDU, and a modified Meteor III, EE397, fittedwith a nose-mounted probe[7] . On 7th August 1949, the Meteor flown by FRL test pilot Pat Hornidge took-off fromTarrant Rushton and, refulled ten times by the Lancaster tanker, remained airborne for 12 hours and 3 minutes,receiving 2,352 gallons of fuel from the tanker in ten tanker contacts and flying an overall distance of 3600 miles(5800 km), achieving a new jet endurance record.[8] FRL still exists as part of Cobham plc.

Modern specialized tanker aircraft have equipment specially designed for the task of offloading fuel to the receiveraircraft, based on Hunter's design, even at the higher speeds modern jet aircraft typically need to remain airborne.

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Operational useIn January 1948, General Carl Spaatz, then the first Chief of Staff of the new United States Air Force made aerialrefueling a top priority of the service. In March 1948 USAF purchased two sets of Cobham's refueling equipment,which had been in practical use with British Overseas Airways Corporation (BOAC) since 1946, and manufacturingrights to the system. FRL also provided a year of technical assistance. The sets were immediately installed in twoB-29 Superfortresses, with plans to equip 80 B-29s.Flight testing began in May 1948 at Wright-Patterson Air Force Base, Ohio, and was so successful that in Juneorders went out to equip all new B-50's and subsequent bombers with receiving equipment. Two dedicated AirRefueling units were formed on June 30, 1948: the 43rd ARS at Davis-Monthan Air Force Base, Arizona, and the509th ARS at Walker Air Force Base, New Mexico. The first ARS aircraft used a hose refueling system, but testingwith a boom system followed quickly in the autumn of 1948.In 1949 from February 26 to March 3 an American B-50 Superfortress Lucky Lady II of the 43rd Bomb Wing flewnon-stop around the World in 94 hours, 1 min., a feat made possible by three aerial refuelings from four pairs ofKB-29M tankers of the 43rd ARS. Before the mission, crews of the 43rd had experienced only a single operationalair refueling contact. The flight started and ended at Carswell Air Force Base in Fort Worth, Texas with therefuelings accomplished over West Africa, the Pacific ocean near Guam and between Hawaii and the West Coast.This first non-stop circumnavigation of the globe proved that, because of aerial refueling, vast distances andgeographical barriers were no longer an obstacle to military air power. In 1949 four additional ARS units wereorganized by the USAF and both the 43rd and 509th ARS became fully operational.The first use of aerial refueling in combat took place during the Korean War. Though the KC-135 was envisaged forrefueling strategic bombers, it saw extensive use refueling smaller tactical aircraft in the Vietnam War supportinglarge strike packages. It also was used for in Desert Storm and current US air warfare doctrine. The HC-130 andKC-130 Hercules is used by the US Marine Corps and Navy to refuel jets, and by the US Air Force to refuelhelicopters.

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SystemsThe two most common approaches for making the union between the two aircraft are the boom and receptaclesystem (sometimes called flying boom) and the probe and drogue system. There is also a combination “boom drogueadaptor” that combines the first two methods. Much less popular was the wing-to-wing system, which is no longerused.

Boom and receptacle

USAF C-5 approaches a KC-135R

USAF AWACS approaches a KC-135R

Often called the Boeing "flying boom”, this system uses a rigid,telescoping tube controlled by two small wings that an operator on thetanker aircraft extends and inserts into a receptacle on the receivingaircraft. In practice, the pilot of the aircraft being refueled mustposition the aircraft so that the boom can be engaged, using visualreferences, including lights used during night refueling. Allboom-equipped tankers (i.e. KC-135 Stratotanker, KC-10 Extender),have a single boom, and can refuel one aircraft at a time with thismechanism.

History

In the late 1940s, General Curtis LeMay, commander of the StrategicAir Command (SAC), asked Boeing to develop a refueling system thatcould transfer fuel at a higher rate than had been possible with earliersystems using flexible hoses. Boeing engineers came up with theconcept of the “Flying Boom” system. The B-29 was the first toemploy the flying boom system, and between 1950 and 1951, 116original B-29s, designated KB-29Ps, were converted at the Boeingplant at Renton, Washington. Boeing went on to develop the world’sfirst production aerial tanker, the KC-97 Stratotanker, a piston-enginedBoeing Stratocruiser (USAF designation C-97 Stratofreighter) with aBoeing-developed flying boom and extra kerosene (jet fuel) tanksfeeding the boom. The Stratocruiser airliner itself was developed fromthe B-29 bomber after World War II. In the KC-97, the mixedgasoline/kerosene fuel system was clearly not desirable and it wasobvious that a jet-powered tanker aircraft would be the next development, having a single type of fuel for both itsown engines and for passing to receiver aircraft. It was no surprise that, after the KC-97, Boeing began receivingcontracts from the USAF to build jet tankers based on the Boeing 367-80 (Dash-80) airframe. The result was theBoeing KC-135 Stratotanker, of which 732 were built.

Operation

The flying boom is attached to the rear of the tanker aircraft. The attachment is flexible, allowing boom movementup to 25 degrees left or right, and from flush with the bottom of the aircraft up to 50 degrees below horizontal.Mounted within the outer structural portion of the boom is a rigid tube through which the fuel passes. The tip end ofthe fuel tube has a nozzle attached on a flexible ball joint. The nozzle mates to the "receptacle" in the receiveraircraft during fuel transfer. A poppet valve in the end of the nozzle prevents fuel from exiting the tube until thenozzle properly mates with the receiver's refueling receptacle. Once properly mated, toggles in the receptacle engagethe nozzle, holding it locked during fuel transfer.

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Mounted on the outer structural portion of the boom at the opposite end from where the boom attaches to the tanker(the end where the inner fuel tube exits) are a pair of aerodynamic control surfaces allowing precise two dimensionalpositioning (left/right and up/down) of the boom. These control surfaces, called "ruddevators," provide the samefunctionality as the conventional, tail-mounted rudder and elevator control surfaces of a typical airplane. They areactuated hydraulically and controlled by the system operator using a control stick. Additionally, the system operatormay hydraulically extend and retract the inner fuel tube using the extension/retraction lever, thereby providing forpositioning of the boom nozzle in a third dimension (fore/aft).To complete an aerial refueling, the pilot of the receiver aircraft begins by flying formation in the "precontact"position, a position directly below and approximately 50 feet (15 m) behind the boom nozzle. The boom is flown inthe "trail" position at 30 degrees below horizontal, on the tanker's centerline with the nozzle extended 10 feet(3.0 m). The receiver may be slightly left or right of centerline depending on operational guidance or receptacleinstallation (the refueling receptacle is typically fitted on an aircraft's centerline, but design considerations mayrequire other locations). When cleared, the receiver pilot moves forward–"closes"–aided with either voice (usingradio) or visual commands (using lights on the bottom of the tanker) from the enlisted crew member operating thetanker boom, the "boom operator" or "boomer."On KC-135 tanker aircraft, the boomer lies prone on a couch or pallet; on the KC-10 the boomer sits upright. Oneither tanker, the boomer's position is in the back of the aircraft, facing aft, allowing an unobstructed view of thereceiver aircraft and the boom through an aft-facing window. Once the receiver aircraft reaches a position in whichthe nozzle may be safely mated with the receptacle–the "contact position"–its pilot attempts to hold in that position,allowing as little relative motion between the two aircraft as possible. While the receiver holds in the contactposition, the boomer uses the ruddevator control stick and the extension/retraction lever to precisely position theboom's nozzle into the receiver's receptacle. Following toggle engagement–or "contact"–pumps operated by thetanker's pilot force fuel through the inner fuel tube of the boom into the receiver.

USAF KC-135R boom operator view

While in contact, two rows of lights on the bottom of the tanker'sfuselage–called pilot director indicators–change in relation to thenozzle's up/down and fore/aft movement to aid the receiver pilot inmaintaining position within the air refueling envelope. The "airrefueling envelope" is an area in relation to the tanker within which thenozzle and receptacle must remain during contact. Its boundaries arebased on mechanical boom movement limitations, and to prevent thereceiver from moving into a position where any portion of the boommight touch the receiver outside the receptacle while in contact.Exceeding an air refueling envelope limit can result in structural

damage to the tanker and/or the receiver precluding further refueling operations for either or both.

The boom's mechanical limits are based on the structure of the yoke and trunnion system mounting the boom to thetanker, the length of the extendable inner fuel tube and the maximum deflection of the flexible nozzle. Exceedingmechanical limits can physically break structural parts mounting the boom to the tanker. Exceeding the nozzle'sdeflection limits can cause mechanical binding between the nozzle and receptacle (try removing a key from a lock bypulling sideways instead of straight back) and possible separation of the nozzle from the boom. Should the receivermove too far forward and push the inner fuel tube to its retraction limit, the outer structural portion of the boomcould contact the receiver aircraft and damage both the boom and receiver; too far aft, and the nozzle locked in thereceptacle could be physically broken from the boom when the inner fuel tube reaches its extension limit.Air refueling envelope limits may also be receiver based. For example, a receiver with a receptacle mounted on thefuselage behind a canopy might have to limit upward movement while in contact to prevent the boom from hittingthe canopy. Additionally, large receivers can adversely affect boom control resulting in envelope limitations.

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As the crewmember with the best view of the operation, the boomer is primarily responsible for preventing damageto either aircraft during air refueling. While in contact, the boomer positions the ruddevator control stick to maintainboom/receptacle alignment in response to receiver aircraft left/right and up/down movement, thereby minimizingside forces on the mated nozzle/receptacle. A "freewheeling" extension/retraction motor allows the inner fuel tube toextend and retract as the receiver moves fore and aft. The boomer must monitor the receiver's position, via threeboom position indicators, and command a disengagement of the nozzle/receptacle locking toggles–a"disconnect"–before the receiver aircraft exceeds any published air refueling envelope limit. If the boomerdisconnects before the receiver get the full fuel offload, the entire operation–precontact, closure and contact–repeats.When the desired amount of fuel has passed from tanker to receiver, the boomer or receiver pilot, typically theboomer, commands a disconnect. Disconnect might also occur automatically should the receiver's fuel system befilled to capacity (a sensor monitors fuel pressure during refueling to prevent a rupture in the fuel lines or tanks).Following disconnect, the boomer retracts the fuel tube from the receptacle and flies the boom clear of the receiver.While not in use, the boom is flown or hoisted (via a cable and hydraulic pump) to the stowed position, flush withthe bottom of the tanker, and latched in position to minimize drag. The receiver backs away and clears the tanker,then continues on its mission.

Systems in service

RAF TriStar refuelling US Navy F/A-18s

USAF fixed wing aircraft use the flying boom system exclusively. Inaddition to the US Air Force, the boom system is in use by theNetherlands (KDC-10), Israel (modified Boeing 707), and Turkey(ex-USAF KC-135R). The largest tanker aircraft that ever enteredservice are the Islamic Republic of Iran Air Force (IRIAF) 747's, Irantook delivery of Boeing 747 tankers equipped with a single boom andthree drogues in early 1976. Both Japan and Italy have contracted withBoeing for tankers based on the B767.The European EADS group has developed a boom refueling systemusing "fly-by-wire" controls that is compatible with other boomsystems. This is offered on modified European Airbus type aircraft thatare configured as tankers.

Advantages

• Higher fuel flow rates (up to 1000 US gallons/6,000 lb per minute for the KC-135 tanker) can be achieved withthe large diameter of the pipe in the flying boom, resulting in much less time required to refuel compared to thesmaller diameter required of a flexible hose system. Unlike bombers and other large aircraft, however, fighteraircraft can only ‘’accept’’ fuel at 1000–3000 lb per minute and cannot use the boom’s maximum flow rate. Theflying boom, therefore, loses its primary advantage over the hose-and-drogue system when refueling fighteraircraft[9] and requires a reduction in refueling pressure when servicing these aircraft.[10]

• The boom method eliminates the requirement for the (often very large and less maneuverable) receiver aircraftpilot to precisely fly a probe into a drogue, something that is easily performed by fighter-sized aircraft, but wouldbe extremely challenging even for the best pilot in a larger aircraft.

• A tanker with a flying boom can be converted in the field to accommodate probe-equipped aircraft, if necessary.

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Disadvantages

• The cost to train and employ the "boomer" and other large tanker crew.• Incompatibility with probe and drogue systems, which are prevalent on US Navy, and most non-US aircraft.• Complexity of tanker design.• Only one receiver aircraft can refuel at a time.• Smaller aircraft (fighter size), can only accept fuel at 1–3,000lbs/min.• Cannot be used to refuel most helicopters.• Cannot be installed on carrier based aircraft.

Probe and drogue

Tornado GR4 refueling from the drogue of anRAF VC10 tanker over Iraq.

The nose probe on an RAF maritime patrolNimrod MR2

This refueling method employs a flexible hose that trails from thetanker aircraft. The drogue (or para-drogue), sometimes called abasket, is a fitting resembling a windsock or shuttlecock, attached at itsnarrow end with a valve to a flexible hose. The drogue stabilizes thehose in flight and provides a funnel to aid insertion of the receiveraircraft probe into the hose. The hose connects to a Hose Drum Unit(HDU). When not in use, the hose/drogue is reeled completely into theHDU. The receiver has a probe, which is a rigid arm placed on theaircraft's nose or fuselage. This probe is often retracted when not inuse, particularly on high speed aircraft. At the end of the probe is avalve that is closed until it mates with the drogue, after which it opensand allows fuel to pass from tanker to receiver. The valves in the probeand drogue that are most commonly used are to a NATO standard andwere originally developed by the company Flight Refuelling Limited inthe UK and deployed in the late 1940s and 1950s. This standardizationallows drogue-equipped tanker aircraft from many nations the ability torefuel probe-equipped aircraft from other nations. The NATO standardprobe system incorporates shear rivets that attach the refueling valve tothe end of the probe. This is so that if a large side-load or up-and-download develops while in contact with the drogue, the rivets shear and thefuel valve breaks off rather than the probe or receiver aircraft sufferingstructural damage. A so-called "broken probe" (actually a broken fuelvalve, as described above) may happen if poor flying technique is used by the receiver pilot, or in turbulence.Sometimes the valve is retained in the tanker drogue and prevents further refueling from that drogue until removedduring ground maintenance.

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Buddy store

F/A-18 buddy refueling

A "buddy store" or “buddy pod” is an external pod loaded on an aircrafthardpoint that contains a hose and drogue system HDU.[11] Buddystores allow fighter / bomber aircraft to be reconfigured for "buddytanking" other aircraft. This allows an air combat force withoutdedicated/specialized tanker support (for instance, a carrier air wing) toextend the range of its strike aircraft. In other cases, using the buddystore method allows a carrier-based aircraft to take-off with a heavierthan usual load, the aircraft then being 'topped up' with fuel from aHDU-equipped 'buddy' tanker, a method previously used by the RoyalNavy in operating its Supermarine Scimitar and Blackburn Buccaneers,in the Buccaneer's case using a bomb-bay-mounted tank and HDU.

Operation

The tanker aircraft flies straight and level and extends the hose/drogue which is allowed to trail out behind and belowthe tanker under normal aerodynamic forces. The pilot of the receiver aircraft extends his probe (if required) anduses normal flight controls to "fly" the refueling probe directly into the basket. This requires a closure rate ofapproximately two knots (walking speed) in order to establish solid probe/drogue couple and pushing the hoseseveral feet into the HDU. Too little closure will cause an incomplete connection and no fuel flow (or occasionallyleaking fuel). Too much closure is dangerous because it can trigger a strong transverse oscillation in the hose,severing the probe tip. Another significant danger is that the drogue may hit the recipient aircraft and damageit—instances have occurred in which the drogue has shattered the canopy of a fighter aircraft, causing great dangerto its pilot.The optimal approach is from behind and below (not level with) the drogue. Because the drogue is relatively light(typically soft canvas webbing) and subject to aerodynamic forces, it can be pushed around by the bow wave ofapproaching aircraft, exacerbating engagement even in smooth air. After initial contact, the hose and drogue ispushed forward by the receiver a certain distance (typically, a few feet), and the hose is reeled slowly back onto itsdrum in the HDU. This opens the tanker's main refueling valve allowing fuel to flow to the drogue under theappropriate pressure (assuming the tanker crew has energized the pump). Tension on the hose is aerodynamically"balanced" by a motor in the HDU so that as the receiver aircraft moves fore and aft, the hose retracts and extends,thus preventing bends in the hose that would cause undue side loads on the probe. Fuel flow is typically indicated byillumination of a green light near the HDU. If the hose is pushed in too far or not far enough, a cutoff switch willinhibit fuel flow, which is typically accompanied by an amber light. Disengagement is commanded by the tankerpilot with a red light.[11]

S-3 Viking buddy tanker with drogue deployed

Systems in service

USAF helicopters, and all US Navy and Marine Corps aircraft refuelusing the “hose-and-drogue.” NATO countries and other western alliesalso refuel with the hose-and drogue. The probe-and-drogue systemwas first used in service on late models of the KB-29M Superfortress.Its first use in combat occurred on May 29, 1952 when twelve F-84swere refueled during a mission from Itazuke, Japan to Sariwon, NorthKorea. Also in the 1950s, the Royal Air Force converted twosquadrons of Valiant bombers to the tanker role by mounting a Hose

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Drum Unit (HDU) in the bomb bay. These were No. 214 Squadron RAF at Marham, operational in 1959, and laterNo. 90 Squadron RAF at Honington. In the 1960s the Valiant was replaced by Victor tankers that had up to threerefueling points, one under the fuselage and a pod under each wing.

Advantages

• Simpler/cheaper tanker design.• The probe-and-drogue method allows aircraft not originally designed as tankers to be converted by attaching a

refueling pod.• Tankers can be equipped with multipoint hose-and-drogue systems allowing two (or more) aircraft to refuel

simultaneously from the same tanker, reducing time spent by as much as 75% for a four aircraft strikepackage.[12] Multiple refueling points also offers redundancy over the single boom system.

• Can be used to refuel properly equipped helicopters, such as the MH-53E Sea Dragon.• No boom operator is needed for the refueling as the drogue can be operated by the pilot of the tanker.

Disadvantages

• The lower flow rates (1,500–2,000 lbs/min)[13] available from the lower pressure and limited diameter of the hoseused in the probe-and-drogue system result in longer refueling times compared to the flying boom for largeraircraft.

• Drogue subject to turbulence and aerodynamic forces (bow wave) of approaching aircraft.• Drogue subject to damage by poor receiver technique, making further refueling difficult or impossible.• Precise placement of the probe into the drogue by the receiver aircraft pilot precludes large receiver aircraft

installation.• Drogue only equipped tankers cannot be easily fitted with boom systems.• The probe is generally located in the front of the refueling plane, presenting several problems: sensitive avionics

equipment (pitot static and angle of attack probes, etc.), can easily be damaged by the drogue, and FOD, includingfuel or probe/drogue parts can be ingested into the plane's engines.

Boom drogue adapter units

Cockpit view of KC-135 boom in the US Navy"Iron Maiden" configuration.

USAF KC-135 and French Air Force KC-135FR refueling-boomequipped tankers can be field converted to a probe-and-drogue systemusing a special adapter unit. In this configuration, the tanker retains itsarticulated boom, but has a hose/drogue at the end of it instead of theusual nozzle. The tanker boom operator holds the boom in a staticposition, while the receiver aircraft then flies the probe into the basket.Unlike the soft canvas basket used in most drogue systems, the adapterunits used on adapter units use a steel basket, grimly known as the“iron maiden” by naval aviators because of its unforgiving nature. Softdrogues can be contacted slightly off center, wherein the probe isguided into the hose receptacle by the canvas drogue. The metal

drogue, when contacted even slightly off center, will pivot out of place, potentially “slapping” the aircraft’s fuselageand causing damage.

The other major difference with this system is that when contacted, the hose does not “retract” into an HDU. Instead,the hose bends depending on how far it is pushed toward the boom. If it is pushed too far, it can

Aerial refueling 10

Air National Guard KC-135 tanks a US NavyHornet

loop around the probe or nose of the aircraft, damage the windscreen,or cause contact with the rigid boom. If not pushed far enough, theprobe will disengage, halting fueling. Because of a much smallerposition keeping tolerance, staying properly connected to a KC-135adapter unit is considerably more difficult than staying in a traditionalhose/drogue configuration. When fueling is complete, the receivercarefully backs off until the probe refueling valve disconnects from thevalve in the basket. Off center disengagements, like engagements, cancause the drogue to “prang” the probe and/or strike the aircraft’sfuselage.

Multiple systems

Australian KC-30A tanker. Visible are twohose-and-drogue systems and a centerline boom.

Some tankers have both a boom and one or more completehose-and-drogue systems. Where these are attached to the wings,the system is known as the Multi-Point Refueling System orMPRS. The USAF KC-10 has both a flying boom and also aseparate hose and drogue system manufactured by Cobham plc.Both are on the aircraft centerline at the tail of the aircraft, so onlyone system can be used at once. However, such a system allows alltypes of probe- and receptacle-equipped aircraft to be refueled,including large aircraft that are probe-equipped and do not havethe maneuverability to take fuel from an off-centerline wing pod.Many KC-135 and some KC-10s are also equipped with dualunder-wing hose-and-drogue attachments known as Wing Air Refueling Pods (WARPs).

Wing-to-wingIn this method, similar to the probe and drogue method but more complicated, the tanker aircraft released a flexiblehose from its wingtip. An aircraft, flying beside it, had to catch the hose with a special lock under its wingtip. Afterthe hose was locked, and the connection was established, the fuel was pumped. It was used on a small number ofSoviet Tu-4 and Tu-16 only (the tanker variant was Tu-16Z).

GrapplingSome historic systems used for pioneering aerial refueling used the grappling method, where the tanker aircraftunreeled the fuel hose and the receiver aircraft would grapple the hose midair, reel it in and connect it so that fuelcan be transferred either with the assistance of pumps or simply by gravity feed. This was the method used on theQuestion Mark endurance flight in 1929, and also the first ever non-stop around-the-world flight by Strategic AirCommand's B-50 nuclear-capable bomber nicknamed the Lucky Lady II in 1949.

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Compatibility issuesThe probe-and drogue system is not compatible with flying boom equipment, creating a problem for militaryplanners where mixed forces are involved. For this reason (as well as other advantages of probe/drogue systems), theUSAF has considered converting boom systems to probe-and-drogue.[14]

Uses and considerations

An F-15E Strike Eagle disengages from a KC-10Extender, using a boom with an He 162 style of

control surface

Strategic

The development of the KC-97 and KC-135 Stratotankers was pushedby the Cold War requirement of the United States to be able to keepfleets of nuclear-armed B-47 Stratojet and B-52 Stratofortress strategicbombers airborne around-the-clock either to threaten retaliation againsta Soviet strike for mutual assured destruction, or to bomb the U.S.S.R.first had it been ordered to do so by the President of the United States.The bombers would fly orbits around their assigned positions fromwhich they were to enter Soviet airspace if they received the order, andthe tankers would refill the bombers' fuel tanks so that they could keepa force in the air 24 hours a day, and still have enough fuel to reachtheir targets in the Soviet Union. This also ensured that a first strikeagainst the bombers' airfields could not obliterate the U.S.'s ability toretaliate by bomber. A noted example of refueling used in this mannerin the movies can be seen in the opening credits of Dr. Strangelove.

In the UK, in 1958 Valiant tankers were developed with one HDUmounted in the bomb-bay. Valiant tankers were used to demonstrateradius of action by refueling a Valiant bomber non-stop from UK toSingapore in 1960 and a Vulcan bomber to Australia in 1961. OtherUK exercises involving refueling aircraft from Valiant tankersincluded Javelin and Lightning fighters, also Vulcan and Victor bombers. For instance, in 1962 a squadron of Javelinair defense aircraft was refueled in stages from the UK to India and back (exercise "Shiksha"). After the retirementof the Valiant in 1965, the Handley Page Victor took over the UK refueling role and had three hoses (HDUs). Thesewere a fuselage-mounted HDU and a refueling pod on each wing. The center hose could refuel any probe-equippedaircraft, the wing pods could refuel the more maneuverable fighter/ground attack types.

A byproduct of this development effort and the building of large numbers of tankers was that these tankers were alsoavailable to refuel cargo aircraft, fighter aircraft, and ground attack aircraft, in addition to bombers, for ferrying todistant theaters of operations. This was much used during the Vietnam War, when many aircraft could not havecovered the transoceanic distances without aerial refueling, even with intermediate bases in Hawaii and Okinawa. Inaddition to allowing the transport of the aircraft themselves, the cargo aircraft could also carry matériel, supplies, andpersonnel to Vietnam without landing to refuel. KC-135s were also frequently used for refueling of air combatmissions from air bases in Thailand.The USAF SR-71 Blackbird strategic reconnaissance aircraft made frequent use of air-to-air refueling. Indeed, design considerations of the aircraft made its mission impossible without aerial refueling. Based at Beale AFB in central California, SR-71s had to be forward deployed to Europe and Japan prior to flying actual reconnaissance missions. These trans-Pacific and trans-Atlantic flights during deployment were impossible without aerial refueling. The SR-71's designers traded takeoff performance for better high-speed, high-altitude performance, necessitating takeoff with less-than-full fuel tanks from even the longest runways. Once airborne, the Blackbird would accelerate

Aerial refueling 12

to supersonic speed using afterburners to facilitate structural heating and expansion. The magnitude of temperaturechanges experienced by the SR-71, from parked to its maximum speed, resulted in significant expansion of itsstructural parts in cruise flight. To allow for the expansion, the Blackbird's parts had to fit loosely when cold, soloosely, in fact, that the Blackbird constantly leaked fuel before heating expanded the airframe enough to seal its fueltanks. Following the supersonic dash, and to stop the fuel leaks, the SR-71 would then rendezvous with a tanker tofill its now nearly empty tanks before proceeding on its mission. At its most efficient altitude and speed, theBlackbird was capable of flying for many hours without refueling. The SR-71 used a special fuel, JP-7, with a veryhigh flash point to withstand the extreme skin temperatures generated during Mach 3+ cruise flight. While JP-7could be used by other aircraft, its burn characteristics posed problems in certain situations (such as high-altitude,emergency engine starts) that made it less than optimal for aircraft other than the SR-71.Normally, all the fuel aboard a tanker aircraft may be either offloaded, or burned by the tanker as necessary. Tomake this possible, the KC-135 fuel system incorporated gravity draining and pumps to allow moving fuel from tankto tank depending on mission needs. Mixing JP-7 with JP-4 or Jet A, however, rendered it unsuitable for use by theSR-71, so the US Air Force commissioned a specially modified KC-135 variant, the KC-135Q, which includedchanges to the fuel system and operating procedures preventing inadvertent inflight mixing of fuel intended foroffload with fuel intended for use by the tanker. SR-71 aircraft were refueled exclusively by KC-135Q tankers.

A KC-10 Extender from Travis Air Force Base,California, refuels an F-22 Raptor

Tactical

Tankers are considered "force multipliers," because they conveyconsiderable tactical advantages. Primarily, aerial refueling adds to thecombat radius of attack, fighter and bombers aircraft, and allows patrolaircraft to remain airborne longer, thereby reducing the numbers ofaircraft necessary to accomplish a given mission. Aerial refueling canalso mitigate basing issues which might otherwise place limitations oncombat payload. Combat aircraft operating from airfields with shorterrunways must limit their takeoff weight, which could mean a choicebetween range (fuel) and combat payload (munitions). Aerial refueling,however, eliminates many of these basing difficulties because acombat aircraft can takeoff with a full combat payload and refuelimmediately.

Aside from these issues, the psychological advantage of full fuel tanks– and a tanker likely available nearby – gives a pilot a distinct edge incombat. In most combat situations, speed is life – the faster your

aircraft is moving, the greater the tactical advantage for you, and the greater the tactical difficulty for your foe. Butspeed requires fuel, so the prudent pilot must balance the need for speed with the need to get home. Pilots flyingaircraft with aerial refueling capability all but eliminate low-fuel concerns and can maintain life-saving speed as longas necessary (for all practical purposes) to meet mission and tactical needs. This psychological advantage cannot beover-emphasized.

Vietnam War

During the Vietnam War, it was common for USAF fighter-bombers flying from Thailand to North Vietnam torefuel from KC-135s en-route to their target. Besides extending their range, this enabled the F-105s and F-4Phantoms to carry more bombs and rockets. Tankers were also available for refueling on the way back if necessary.In addition to ferrying aircraft across the Pacific Ocean, aerial refueling made it possible for battle damaged fighters,with heavily leaking fuel tanks, to hook up to the tankers and let the tanker feed its engine(s) until the point wherethey could glide to the base and land. This saved numerous aircraft.

Aerial refueling 13

The US Navy frequently used carrier-based aerial tankers like the KA-3 Skywarrior to refuel Navy and Marineaircraft such as the F-4, A-4 Skyhawk, A-6 Intruder, and A-7 Corsair II. This was particularly useful when a pilotreturning from an airstrike was having difficulty landing and was running low on jet fuel. This gave him fuel formore attempts at landing for a successful "trap" on an aircraft carrier. The KA-3 could also refuel fighters onextended Combat Air Patrol. USMC jets based in South Vietnam and Thailand also used USMC KC-130 Herculestransports for air-to-air refueling on missions.

Iran-Iraq War

During the 1980s war, the Iranian Air Force maintained at least one KC 707-3J9C aerial tanker, which the IslamicRepublic had inherited from the Shah's government. This was used most effectively on April 4 1981, refueling eightIRIAF F-4 Phantoms on long range sorties into Iraq to bomb the H-3 Al Walid airfield near the Jordanian border.[15]

Falklands War

Argentine Super Etendard

During the Falklands War, aerial refueling played a vital role in all ofthe Argentine successful attacks against the Royal Navy. TheArgentine Air Force had only two KC-130H Hercules available andthey were used to refuel both Air Force and Navy A-4 Skyhawks andNavy Super Etendards in their Exocet strikes. The Hercules on severaloccasions approached the islands (where the Sea Harriers were inpatrol) to search and guide the A-4s in their returning flights. On oneof those flights (callsign Jaguar) one of the KC-130s went to rescue adamaged A-4 and delivered 39000 lb (18000 kg) of fuel while carryingit to its airfield at San Julian.

On the other hand, the Mirage IIIs and Daggers lack of air refueling capability prevented them from achieving betterresults. The Mirages were unable to reach the islands with a strike payload, and the Daggers could do so only for afive minute strike flight.

On the British side, air refueling was carried out by the Handley Page Victor K.2 and after the Argentine surrenderby modified C-130 Hercules tankers. These aircraft aided deployments from the UK to the Ascension Island stagingpost in the Atlantic and further deployments south of bomber, transport and maritime patrol aircraft. The mostfamous refueling missions were the 8,000nm/15,000km "Operation Black Buck" sorties which needed 14 Victortankers to refuel a single Avro Vulcan bomber (with both the Vulcan, and many of the Victors needing refueling), toattack the Argentine-captured airfield at Port Stanley on the Falkland Islands. They attempted to knock out the PortStanley runway, blocking the Argentine C-130 Hercules reinforcement operations. The raids were the longest-rangebombing raids in history until surpassed by the B-52 in the 1991 Gulf War and later B-2 flights.The Victor tankers, retired in 1993, were replaced in RAF service by Lockheed L-1011 and Vickers VC10 transportswhich were bought second-hand and fitted as tankers. The L-1011s, converted by Marshall Aerospace, and VC10s,converted by British Aerospace, can refuel any aircraft fitted with the NATO standard probe system.

Aerial refueling 14

Libya

During Operation El Dorado Canyon, several F-111 Aardvark fighter-bombers stationed in the United Kingdom usedaerial refueling to enable them to operate non-stop against targets in Libya. Since the aircraft were allowed to crossneither French nor Spanish airspace, they had to make a detour around the Iberian Peninsula and stay aboveInternational waters during all transit.

Persian Gulf War

F-14 Tomcats from the Red Sea and Persian Gulfawait their turn refueling from a KC-10A over

Iraq during Desert Storm

During the time of Operation Desert Shield, the military build up to thePersian Gulf War, US Air Force KC-135s, McDonnell DouglasKC-10As, and USMC KC-130 Hercules aircraft were deployed toforward air bases in England, Diego Garcia, and Saudi Arabia. Aircraftstationed in Saudi Arabia normally maintained an orbit in theSaudi–Iraqi neutral zone, informally known as "Frisbee", and refueledCoalition Aircraft whenever necessary. Two side by side tracks overcentral Saudi Arabia called "Prune" and "Raisin" featured 2–4 basketequipped KC-135 tankers each and were used by Navy aircraft fromthe Red Sea Battle Force. Large Navy strike groups from the Red Seawould send A-6 tankers to the Prune and Raisin tracks ahead of thestrike aircraft arriving to top off and take up station to the right of thetankers thereby providing an additional tanking point. RAF HandleyPage Victor and VC-10 tankers were also used to refuel British andcoalition aircraft and were popular with the US Navy for their docilebasket behavior and having three point refueling stations. Anadditional track was maintained close to the northwest border for theE-3 AWACS aircraft and any Navy aircraft needing emergency fuel.These 24-hour air-refueling zones helped make the intense aircampaign during Operation Desert Storm possible. An additional 24/7tanker presence was maintained over the Red Sea itself to refuel NavyF-14 Tomcats maintaining Combat Air Patrol tracks. During the last week of the conflict, KC-10 tankers movedinside Iraq to support barrier CAP missions set up to block Iraqi fighters from escaping to Iran.

On January 16–17, 1991, the first combat sortie of Desert Storm, and the longest combat sortie in history, at thattime, was launched from Barksdale AFB, Louisiana. Seven B-52Gs flew a thirty-five hour mission to the PersianGulf region, and back, to launch Boeing Air Launched Cruise Missiles (ALCMs) with the surprise use ofconventional warheads. All of this was made possible by in-flight refueling, and by the secret switch away fromnuclear warheads on the ALCMs.An extremely useful aerial tanker in Desert Storm was the USAF KC-10A Extender. Besides being larger than theother tankers, the KC-10A is equipped with the USAF "boom" refueling and also the "hose-and-drogue" system.This makes it possible for the KC-10A to refuel USAF aircraft, and also USMC and US Navy jets that use the"probe-and-drogue" system, and also allied aircraft, such as those from the UK and Saudi Arabia. KC-135s may beequipped with a drogue depending on the mission profile.The KC-10A was originally designed for the support of NATO in Europe by the USAF. In the case of armedconflict, with a full jet fuel load, the KC-10A is capable of flying from a base on the east coast of the US or Canada,flying nonstop to Europe, transferring a considerable amount of fuel in air-to-air refueling, and then returning to itshome base, all without landing anywhere. This could have been very useful in the case when numerous Europeanbases become disabled by Warsaw Pact strikes in Germany, the Netherlands, France, and Great Britain.

Aerial refueling 15

Kosovo War

The USAF provided nearly 90 percent of the NATO tanker force, 112 active and 63 Reserve-component KC-135and KC-10 tankers.[16] Tankers were also provided from Britain’s RAF (Tristars and VC-10s), French Air Force andTurkish Air Force KC-135s, Spanish Air Force KC-130 Hercules and Royal Netherlands Air Force KDC-10s.Although some European nations provided air-refueling aircraft, the conflict highlighted the problem Europe haswith a lack of such aircraft and dependence on the United States for tanker support during a major operation. SomeEuropean nations sought to address this lack of capability, such as the Italian Air Force purchase of the BoeingKC-767, but there is still a huge difference in air-refueling capability between the US and Europe.

Aerial rearmingIn 2003 the U.S. Air Force and Far Technologies applied secretly for patents on mid-air rearming of aircraft. Thetechnique proposed is similar in many respects to airborne refueling, with a number of notable modifications. Theairborne rearming system comprises a rearming plane with an internal bomb storage area and loading deviceconsisting of a large aft door and a modified remote-driven robotic arm (boom) equipped with a day-night camera aswell as sensors. A special pylon to receive the arms from the boom is fitted onto the attack aircraft. At presentfinancial and technological problems stand in the way of aerial rearming, mainly the need for an automatic system toperform the rearm currently under development for aerial refueling.[17]

Helicopters

Raising a hose from ship to an HH-65

The probe of a AgustaWestland EH101

Helicopter In-Flight Refueling (HIFR) is a variation of aerialrefueling when a naval helicopter approaches a warship (notnecessarily suited for landing operations) and receives fuel through thecabin while hovering.

Alternatively, some helicopters equipped with a probe extending outthe front can be refueled from a drogue-equipped tanker aircraft in asimilar manner to fixed-wing aircraft by matching a high forwardspeed for a helicopter to a slow speed for the fixed-wing tanker.

Developments

• Commercial tankers are increasingly being used by military forces.The Omega Company [18] is contracted by the US Navy.

• Autonomous (hands off) refueling using probe/drogue systems isbeing investigated by NASA, potentially for use by Unmannedaerial vehicles[19] .

Tanker aircraft by refueling system

Aerial refueling 16

Boom and receptacle

A B-2 Spirit prepares to refuel from a KC-135R

• KB-29P (No longer in service)• adapted from the B-29 Superfortress bomber

• KC-97 Stratotanker (No longer in service)• derived from the C-97 Stratofreighter

• KC-135 Stratotanker• related to the Boeing 707 airliner• also used by the French Air Force, Colombian Air Force,

Republic of Singapore Air Force and Turkish Air Force• boom can be fitted preflight with a drogue adapter. French Air

Force KC-135 Stratotankers use the probe and drogue system

• MPRS models will have two drogue hose reels (pods) at the wingtips• KC-10 Extender

• adapted from the McDonnell Douglas DC-10 airliner• also has a retractable hose and drogue that can be selected in-flight• can be fitted with two underwing pods(similar to the KC-135's MPRS) capable of simultaneously refueling

two receiver aircraft (Wing Air Refueling Pods or WARPs)• Boom operator is in a rear-facing seat with a downward facing window with fly by wire controls.• The Royal Netherlands Air Force operates two KDC-10s – former civil aircraft modified to a similar standard

to the KC-10• KC-767

• adapted from the Boeing 767 airliner• to be used by the Italian Air Force and Japan Air Self Defense Force (Entered service on March 26, 2009)

• Airbus A330 MRTT• development of Airbus A330-200 airliner. Australian aircraft will be equipped with both a flying boom and

probe-and-drogue units to accommodate both RAAF F-111s as well as F/A-18s and will be known as KC-30B.UK aircraft will be probe-and-drogue only. The advanced refueling boom system (ARBS) places the boomoperator and mission planning station in the cockpit. It includes remote controls with an enhanced 2D/3Dvision system rather than a rear facing seat in the tail.

de Havilland Sea Vixens probe-and-droguerefuelling at a 1960s Farnborough Air Show

Probe and drogue

• Airbus A330 MRTT• RAF Future Strategic Tanker Aircraft, due in service around

2011.• RAAF due in service mid-2010.

• Airbus A310 MRTT• 4 for Luftwaffe• 2 for Canadian Forces (as CC-150 Polaris)

• Airbus A400M, future strategic transport and tanker aircraft due inservice around 2009.

• Avro Lancaster (retired)• Refueled Gloster Meteors in 1940's

• Avro Lincoln[20] (retired)

Aerial refueling 17

An Australian Boeing 707 refueling a US NavyF/A-18 in 2002

German Luftwaffe Airbus A310 MRTT ready forrefueling, shown at the Paris Air Show 2007

• Refueled Gloster Meteors in 1940's• Avro Vulcan (No longer in service)

• specially modified for operations during the Falklands War• Blackburn Buccaneer (No longer in service)

• Equipped for buddy tanking• Boeing 707

• Used by the Royal Australian Air Force, Brazilian Air Force,Canadian Forces Air Command, South African Air Force andothers

• French Air Force KC-135 Stratotankers use the probe and droguesystem.

• RCAF (later as Canadian Forces) used to use CC-137 Husky(Boeing 707's) for refueling. Both were retired in the late '90's.

• KB-29M (No longer in service)• adapted from the B-29 Superfortress; earlier versions used a

"grappling hose" system; later models used a trueprobe-and-drogue.

• KB-50 (No longer in service)• adapted from the B-50 Superfortress, an improved model of the

B-29 Superfortress.• HC-130 Hercules and KC-130 Hercules, especially in United States

Marine Corps service as well as KC-130s in Argentine Air Force, Brazilian Air Force, Israel Air Force, Republicof Singapore Air Force, Royal Canadian Air Force and Spanish Air Force service.

• variants of the C-130 Hercules• Rafale

• equipped for buddy refueling• Lockheed L-1011 Tristar

• K1 and KC1 variants deployed by the Royal Air Force• Vickers Valiant (No longer in service)• Vickers VC-10• Handley Page Victor (No longer in service)• KA-3B Skywarrior (No longer in service)

• Dedicated tanker variant of the Skywarrior. Primary US Navy tanker from the Vietnam War until retirementprior to Desert Storm.

• A-4 Skyhawk• Equipped for buddy tanking with several nations.

• KA-6D Intruder (No longer in service)• Dedicated tanker variant of the Intruder. Attack variants of the A-6 also capable of buddy tanking

• A-7 Corsair II (No longer in US service)• Equipped for buddy tanking in US Navy and Greek service

• S-3 Viking (No longer in service)• The current primary carrier-based tanker, equipped for buddy tanking

• F/A-18E/F Super Hornet• Equipped for buddy refueling as "Strike tankers". Taking over tanking duties as the S-3 is retired from service.

Aerial refueling 18

• Ilyushin Il-78 Midas

• Standard Russian tanker, adapted from Il-76 cargo/transport aircraft• Variants of this tanker aircraft also deployed by the air forces of Algeria, mainland China, India and Pakistan.

• Myasishchev M-4-2• adapted from the M-4 bomber

• Myasishchev 3MS-2• adapted from the 3M bomber

• Tu-16N (and Tu-16Z with wing-to-wing system)• Hong-6U Tanker

• Su-24M• equipped for buddy refueling with the UPAZ container as "Strike tankers"

• Super Etendard• equipped for buddy refueling

• Su-33• equipped for buddy refueling

• MiG-29K• equipped for buddy refueling

Popular culture• The film The Starfighters has a great deal of footage of F-104 Starfighter jet fighters refueling. This was

extensively mocked when The Starfighters showed up on Mystery Science Theater 3000 as episode #612.• The film Dr. Strangelove from 1964 has genuine footage of a "boom and receptacle" operation between USAF

KC-135 Stratotanker and B-52 Stratofortress in turbulent air.• The film The Perfect Storm contains a scene where an HH-60 helicopter attempts to refuel during adverse

weather, but is unable to succeed. This was based on true events that occurred during the 1991 Perfect Storm.• The film The Final Countdown from 1980 has genuine footage of a "probe and drogue" operation between US

Navy KA-6 Intruder and F-14 Tomcats from USS Nimitz (CVN-68).• The OVA series Macross Zero shows a VF-0 variable fighter refueling from a KS-3 tanker aircraft, while SV-51

variable fighters are seen using the buddy pack system.• The film The Sum of All Fears features a mid-air refueling sequence with the E-4B NEACP. In the commentary,

author Tom Clancy mocks mid-air refueling as "sex between two planes at 35,000 feet".• The film Air Force One shows a CG sequence of a US Air Force KC-10 Extender refueling the hijacked

Presidential aircraft, "Air Force One", a specially converted Boeing 747.• In the 2005 film Stealth the futuristic F/A-37 Talons refuel at an automated aerial refueling station.

Aerial refueling 19

See also• Docking maneuver for spacecraft• Underway replenishment – the transfer of refuel and stores at sea

External links• Photo aerial tanking 1929 [21]

• Aerial tanking history [22]

• Airborne rearming [23] – A comprehensive article including a video.• Aerial Refueling on APA [24]

References[1] Note AAR also stands for "After Action Review" (de-briefing) and in aviation, IFR also stands for "Instrument Flight Rules" (flight by

instrument references only such as in cloud).[2] There is no indication that any relationship exists between A.D. Hunter and the Hunter brothers.[3] http:/ / www. nasm. si. edu/ imagedetail. cfm?imageID=1150[4] History of Aviation, Part 19, 1938[5] Flight Magazine archive, January 10, 1929[6] Flight Magazine archive, July 3, 1931, p623[7] http:/ / www. cobham75. com/ cobham-the-company-1934-1985/ air-to-air-refuelling-takes-off. aspx[8] http:/ / www. the-best-of-british. com/ PlaneCrazyHeritage/ airpictorial/ 1999/ RefuellingFDC. htm[9] KC-135 Aerial Refueling Manual T.O. 1-1C-1-3.[10] Bolkcom, Christopher (2005-05-11). "Air Force Aerial Refueling Methods: Flying Boom versus Hose-and-Drogue" (http:/ / digital. library.

unt. edu/ govdocs/ crs/ permalink/ meta-crs-6702:1). CRS order code RL32910. US Congressional Research Service via CRSWeb. . Retrieved2009-04-01.

[11] A1-F18AC-NFM-000 Naval Aviation Training and Operating Procedures Standardization (NATOPS) Manual. United States Department ofthe Navy. 1 August 2006. pp. 364.

[12] Maj. Marck R. Cobb, “Aerial Refueling: The Need for a Multipoint, Dual-System Capability,” AU-ARI-CP-87-3, Air University Press, July1987.

[13] Air Force Aerial Refueling Methods: Flying Boom versus Hose-and-Drogue (http:/ / fas. org/ sgp/ crs/ weapons/ RL32910. pdf)[14] http:/ / digital. library. unt. edu/ govdocs/ crs/ permalink/ meta-crs-6702:1[15] Air Forces Monthly Special F-4 Phantom ISBN094621946X article by Farzin Nadimi p77[16] Kosovo and Theater Air Mobility (http:/ / www. airpower. au. af. mil/ airchronicles/ apj/ apj99/ win99/ begert. htm)[17] ABRAcadabra – AirBorne ReArming – TFOT (http:/ / www. tfot. info/ content/ view/ 81/ )[18] Omega Air Refueling (http:/ / www. omegaairrefueling. com/ vms/ )[19] Ares Homepage (http:/ / www. aviationweek. com/ aw/ blogs/ defense/ index. jsp?plckController=Blog& plckScript=blogScript&

plckElementId=blogDest& plckBlogPage=BlogViewPost&plckPostId=Blog:27ec4a53-dcc8-42d0-bd3a-01329aef79a7Post:b7a0eae1-e0db-4cf5-b169-2c5633272ceb)

[20] https:/ / www. airforcehistory. hq. af. mil/ Publications/ fulltext/ 75yrs_inflight_refueling. pdf[21] http:/ / www. centennialofflight. gov/ essay/ Evolution_of_Technology/ refueling/ Tech22G1. htm[22] http:/ / www. centennialofflight. gov/ essay/ Evolution_of_Technology/ refueling/ Tech22. htm[23] http:/ / www. tfot. info/ content/ view/ 81/[24] http:/ / www. ausairpower. net/ aar-lift. html

Article Sources and Contributors 20

Article Sources and ContributorsAerial refueling  Source: http://en.wikipedia.org/w/index.php?oldid=371054935  Contributors: -Ril-, Acer, Aiko, Ali@gwc.org.uk, Amckie, Andy Marchbanks, Angusmclellan, Animum,Arpingstone, Art LaPella, Ash sul, Astrowikizhang, Bachcell, BadSeed, BenFrantzDale, BilCat, Blackeagle, BlaiseFEgan, Blue520, Brandmeister, Brian0918, Britmax, Bryan Derksen,Buckboard, CMarshall, Can't sleep, clown will eat me, Capper13, Chris the speller, ChristopherCaufield, Chwyatt, Cjrother, Cmdrjameson, Cometstyles, CommonsDelinker, CubaLibre,Cumbiadude, D2180s, DJ Clayworth, Dalillama, Davin, Deepak, DocWatson42, Doopokko, Dr. Rondart, Drmfreek, Dtom, Duffman, E2a2j, Eagle1335, Echoray, Edison, Emoscopes, Epeefleche,Ephebi, Erudy, Eurosong, Evercat, Evil saltine, F.bendik, Fnlayson, Freakofnurture, Funandtrvl, GCarty, Gaius Cornelius, Gfox88, Gooberliberation, GraemeLeggett, Gsl, H1523702, HJ32,Hamiltondaniel, Hawyih, Heb, HexaChord, Hj108, Hohum, IAC-62, IVP, Ian Dunster, Ian Page, Ian Strachan, Ian W Strachan, Iceberg3k, IddoGenuth, Im a winner, Impi, Ingolfson, Ipankonin,JagSeal, Jfurr1981, Jigen III, Jimwilliams57, Jmerchant29, John, John Darrow, JohnOwens, Jon Harald Søby, Jons63, Jor70, Jormar90, Juliancolton, Jyril, Karl Dickman, Kelly Martin,Kingoomieiii, Koavf, Ksyrie, LedHed430, Lestocq, Lightmouse, Lilac Soul, Lommer, Loren.wilton, Los688, LrdChaos, M.nelson, MJSkia1, Magnus Manske, Makotti, Mark83, Martial75,Massic80, Mboverload, Mgiganteus1, Michalli, Mike Rosoft, MisfitToys, Mistman123, Mo7amedsalim, Mtnerd, Mwarren us, Mwsletten, N328KF, N5iln, Natalie Erin, Necessary Evil,NeilFraser, Nick-D, Nikai, Nixeagle, Noaa, Nuno Tavares, Occasional Reader, Oliverdl, Orca1 9904, OwenBlacker, PPGMD, Pascaly, Patrick, Pibwl, Pill, Pimlottc, Pmsyyz, Premkudva,Preuninger, Qutezuce, RJHall, RadRafe, Raguleader, Rchamberlain, Rebecca, RedWolf, Revth, Riddley, Rjwilmsi, Rogerd, Ryan Roos, SCDBob, Safemariner, Salamurai, SamB135, SaxTeacher,Sc147, Scienda, Scientizzle, Scott Wilson, Sekicho, SimonP, SkyWalker, Sliceofmiami, Snoyes, Some standardized rigour, Stephantom, TGC55, Tabletop, Takavar92, Tdadamemd, Tdrss, ThePIPE, Theptyza, Thumperward, Tierce, TimBentley, Tom harrison, Trekphiler, Trisar, Vianello, Welshie, Winston365, Wirehead, Witan, Wmahan, Wo st 01, WonRyong, Worthawholebean, X!,Xtremdav45, Yamaka122, 255 anonymous edits

Image Sources, Licenses and ContributorsImage:C17 Globmaster refueling from KC135 Stratotanker.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:C17_Globmaster_refueling_from_KC135_Stratotanker.jpg  License:unknown  Contributors: Tech Sgt Shane A. CuomoImage:usaf.f15.f16.kc135.750pix.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Usaf.f15.f16.kc135.750pix.jpg  License: unknown  Contributors: Bapho, Denniss, Joshbaumgartner,PMG, Timak, WonYongImage:Helicopter aerial refueling.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Helicopter_aerial_refueling.jpg  License: unknown  Contributors: Akinom, Bapho, Cobatfor,Denniss, Duffman, Joshbaumgartner, KTo288, Mattes, PMG, Para, 2 anonymous editsImage:Refueling, 1923.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Refueling,_1923.jpg  License: Public Domain  Contributors: no creditImage:refuelling.750pix.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Refuelling.750pix.jpg  License: Public Domain  Contributors: Arpingstone, Bapho, Cobatfor, Denniss, PMG,Stan Shebs, WonYong, 1 anonymous editsImage:Galaxy 03.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Galaxy_03.jpg  License: unknown  Contributors: Akinom, Bapho, CristianChirita, Denniss, PMG, Thuresson,WonYong, 1 anonymous editsImage:Kc135awacs.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Kc135awacs.jpg  License: Creative Commons Attribution 3.0  Contributors: Jormar90Image:KC-135Boom-operator-521.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:KC-135Boom-operator-521.jpg  License: unknown  Contributors: Fr33kman, KTo288,Nobunaga24, Premkudva, 2 anonymous editsFile:RAF Tristar USN F-18C Afghanistan Oct2008.jpeg  Source: http://en.wikipedia.org/w/index.php?title=File:RAF_Tristar_USN_F-18C_Afghanistan_Oct2008.jpeg  License: PublicDomain  Contributors: U.S. DoD photo by Cmdr. Erik Etz, U.S. NavyImage:GR4 VC10.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:GR4_VC10.jpg  License: unknown  Contributors: Mate Class 2nd Peter J. CarneyFile:nimrod mr2 xv226 nosecloseup arp.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Nimrod_mr2_xv226_nosecloseup_arp.jpg  License: Public Domain  Contributors:Arpingstone, CobatforImage:F-18 Buddy Refueling.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:F-18_Buddy_Refueling.jpg  License: Public Domain  Contributors: US NavyImage:S-3 Viking in-flight refueling.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:S-3_Viking_in-flight_refueling.jpg  License: Public Domain  Contributors: Photographer's Mate3rd Class Christopher StephensImage:KC135 boom.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:KC135_boom.jpg  License: Public Domain  Contributors: RasmussenImage:KC135 tanks FA18.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:KC135_tanks_FA18.jpg  License: Public Domain  Contributors: RasmussenFile:A-330-200 MRTT Australia (2).JPG  Source: http://en.wikipedia.org/w/index.php?title=File:A-330-200_MRTT_Australia_(2).JPG  License: Creative Commons Attribution-Sharealike 3.0 Contributors: User:OutisnnImage:F-15 wingtip vortices.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:F-15_wingtip_vortices.jpg  License: unknown  Contributors: Akinom, Bapho, Dual Freq, Saperaud, 1anonymous editsImage:Wing.two.arp.600pix.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Wing.two.arp.600pix.jpg  License: unknown  Contributors: Bapho, Denniss, Makthorpe, Nobunaga24,PMG, WonYongImage:SUEreabasteciendo1.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:SUEreabasteciendo1.jpg  License: Creative Commons Attribution 2.5  Contributors: Martín OteroImage:Tomcats DS tanking DN-ST-91-07919.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Tomcats_DS_tanking_DN-ST-91-07919.jpg  License: Public Domain  Contributors:LCDR PARSONSFile:HIFR(MVC-006S).JPG  Source: http://en.wikipedia.org/w/index.php?title=File:HIFR(MVC-006S).JPG  License: Public Domain  Contributors: Akinom, Bapho, Cobatfor, Los688, Mattes,UmherirrenderFile:2010-06-11 EH101 Airforce EDDB 03.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:2010-06-11_EH101_Airforce_EDDB_03.jpg  License: unknown  Contributors: HighContrast, Wo st 01Image:B2 KC-135 Refuel.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:B2_KC-135_Refuel.jpg  License: unknown  Contributors: Mouse Nightshirt, RiddleyImage:sea vixens refuelling arp.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Sea_vixens_refuelling_arp.jpg  License: Public Domain  Contributors: Arpingstone, 1 anonymouseditsImage:33 Sqn.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:33_Sqn.jpg  License: Public Domain  Contributors: Bapho, Cobatfor, Ed g2s, Hohum, MB-one, Nick-D, Pibwl,ZaccariasImage:Airbus A310 MRTT.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Airbus_A310_MRTT.jpg  License: Public Domain  Contributors: User:Dmottl

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