Traditionally the Royal Air Force has used the probe and drogue in-flight refuelling system, contrasting with the US Air Force which uses a flying boom system.
For smaller fast jet aircraft the choice of system makes little difference as under wing pods are easily fitted to most tanker aircraft.
However for larger aircraft that require higher rates of fuel transfer the choice of system can be a major operational issue. In the past when the United Kingdom has procured large aircraft from the USA such as the E3 Sentry it has converted its aircraft to use the probe and drogue system.
Fitting new fuel systems to aircraft that were not designed to take them can be expensive and time consuming. With ever decreasing budgets and numbers of aircraft the RAF is increasingly opting to have no in-flight refuelling capability for its large aircraft.
Currently the RAF operates C17 and RC135 Rivet Joint and Voyager Tankers of which have an in-flight refuelling receiver using only the flying boom system.
In-flight refuelling for large RAF aircraft such as the C130, A400M and E3 Sentry is provided by a high capacity centre line hose fitted to 7 of the RAF’s Voyager Tankers. Two other Voyagers are fitted for but not with the centre line refuelling point.
The RAF’s Voyager Tanker aircraft is capable of operating with its own flying boom system known as the (ARBS).
Currently the RAF relies on USAF tankers to re-fuel the RC 135 Rivet Joint and has an MOU with the Air Tanker consortium allowing this. However if we are ever required to conduct a sovereign operation without American support we may find it difficult to conduct operations.
If, as looks increasingly likely the UK decides to purchase the P8 Poseidon for maritime patrol operations the situation is likely to get even worse. The P8 is relatively short legged compared to the Nimrod and it is highly likely to require in-flight refuelling to be operationally effective, especially in the South Atlantic.
We could take the step to fit the ARBS system to two Voyager aircraft currently fitted for but not with the centre line refuelling system. As far as I can tell it should not be too difficult to do this even on a finished aircraft. Two tankers would be far from ideal but should allow enough sovereign capability to support our P8’s and Rivet Joints if we are ever required to conduct a sovereign operation.
It would also allow us to better provide support to the USAF.
Given that the A400M can actually carry a high capacity centre line refuelling system with almost no modifications to the aircraft it may make even more sense to convert all 9 Voyagers to use the ARBS system.
In the longer term it is probably far cheaper and easier to convert our tankers over to the ARBS system rather than trying to fit hose and drogue refuelling systems to small fleets of specialist aircraft.