On June 27, 1923, at San Diego, California, the first successful in-flight refuelling operation was accomplished. This exploit was repeated on January 10, 1929, by Squadron Leader Weiss.
Thanks to in-flight refuelling, Boeing B 50 “Lucky Lady”, piloted by Captain James Gallagher, went round the world in 54 hours, from February 29 to March 2, 1949.
Before long, the air staff started being eager to extend the flight duration of their fighter aircrafts and bombers. To this end, they had two options at their disposal: either increase the quantity of fuel at take-off at the expense of the aircraft’s load capacity, or make the plane take off with minimum fuel and maximum payload. The latter scenario of course necessitated in-flight refuelling.
Considering their low power, the planes used during the First World War and even those used in the Second World War could not afford to refuel fighter aircrafts or bombers. The key that opened the door to success was the invention of the jet engine, with the creation, just before the end of the Second World War, of Boeing KC 135, which was subsequently transformed into Boeing 707 and used in civil aviation.
A glory-deficient, yet exacting mission
The East-West tension brought about the creation of NATO and the Strategic Air Command. All round the clock, B36 and subsequently B52 planes were flying without respite, thereby becoming dependent on in-flight refuelling. Two hundred and fifty tanker aircrafts of the US Air Force shouldered this glory-deficient, yet exacting mission of in-flight refuelling. Tankers fly irrespective of the time, and it is this speciality that witnessed the mobilization of almost entirely feminine crews. The training necessary was extremely harsh, especially within the contemporary atomic war context. Pilots flew without flash curtains, wearing just a blindfold across one eye (atomic flash at high altitude irreparably burns the retina).
NB: The explosion of an atomic bomb at high altitude generates an EMP effect which also destroys all electronic equipment containing unhardened semiconductors.
In-flight refuelling rapidly extended to fighter aircrafts, chronically short of fuel. This was done using fighter-bombers when their offensive gears had been jettisoned and an in-flight refuelling pod mounted on them. Taking advantage of this breakthrough, the Fleet Air Arm increased its weapon-carrying capacity. Paradoxically, planes of the Navy had to be equipped with a fuel dumping system as with filled-up tanks, they ran the risk of destroying the undercarriage of their carriers upon landing.
France in need of an aircraft refueller for its Mirage IV
The Mirage IV, meant to be an atomic vector, had legs too short to be able to make a round trip especially as its penetration mission had to be done at supersonic speed, and as, at low altitude, it was a real fuel drain.
The air staff opted for the KC135, an in-flight refueller which was already in use within the Strategic Air Command. In the summer of 1962, a commission went to the US and upon return made recommendations on modifications to be brought to the standard edition. Further down, we will see what these modifications were. In any case, in August 1962, the State of France placed an order for 12 aircrafts. In November 1962, a coordination cell was set up within the EMAA. Late November 1962, a KC 135 from the US Air Force came to Istres to perform an in-flight refuelling simulation on a Mirage IV.
In March 1963, the first French crew left for training in the US, where, from August 1963, eight successive training courses were held. As from February 1964, the French crews returned to France with aircrafts delivered by the Boeing company.
In October 1964, the “Gascogne” bombardment squadron on Mirage IV and the 4/91 “Landes” in-flight refuelling squadron on C135 F were officially declared operational at the Mont de Marsan base. A fortnight later, they responded to an operational warning signal in 15 minutes from a Mirage IV carrying the French nuclear weapon (a 70-kilotonne plutonium AN11 bomb).
For its AWACS and fighter-bombers
KC135 F became KC135 FR following a sweeping overhaul operation during which its old engines were replaced with more powerful, but less voracious 10-tonne thrust CFM 56 engines. It became the pivot of the FAS as it could refuel in-flight all the various types of planes used by the air force such as AWACS, fighters and bombers. It was equipped with a central flying boom for the refuelling of AWACS, fighters and bombers having this system, and also had two wing-tip nacelles that could be used in refuelling two fighters simultaneously.
KC 135 FR, a real “skivvy”
From the onset, the air staff completely modified the internal layout of KC135 US. Steel was put on the floor of the freighter so that it could support heavier loads compared with the load capacity of the wooden floor of KC 135A. As such, the inside of the freighter could be arranged in several ways, thereby conferring extra versatility on this outstanding plane. When used as a refueller, KC135-FR could carry between 83 and 89 tonnes in its wings and fuselage, as well as under the floor of the freighter.
It could also transport:
126 passengers sitting on separate seats or on the side-facing bench seat
Or 42 stretchers when used as an “EVASAN”
Or 7 palettes of 3.6 tonnes of freigh
Finally, it can be converted into a VIP mode, with a bed and an office.
Major specifications of the plane
Model : Boeing stratotanker KC 135 FR
Engines: 4 x CFL F108-CF 100 with a 10-tonne thrust each