The U.K. Royal Air Force has retired the last of its vintage Vickers VC10 aerial refueling tankers, which opens an unlikely capability gap.

For almost 50 years, the VC10 provided strategic transport, airlift and an aeromedical capacity. In the 1980s, with the arrival of several secondhand ex-airline VC10s, the role was extended to provide air-to-air refueling, a capability for which the type became best-known. Of the 54 VC10s produced by Vickers, the RAF operated 28, in four different versions.

Now the mantle of aerial refueling has been taken up by the last six remaining Lockheed L-1011 Tristars, due to exit service in May 2014, and by the expanding fleet of Airbus A330-200 multirole tanker transports, known in RAF service as Voyagers, and operated by the AirTanker consortium under the Future Strategic Transport Aircraft contract.

However, the Voyager will not be fulfilling a once-secretive mission carried out by the VC10—that of air sampling. The VC10 inherited the mission following the retirement of the Avro Vulcan in the 1980s. The missions, part of international nuclear-verification efforts, were often flown in conjunction with the U.S. Air Force's Boeing WC-135B “Constant Phoenix” in the aftermath of nuclear tests, such a those carried out by North Korea in 2006 and 2009 and following India and Pakistan's nuclear trials in 1998. The aircraft used a specially designed particulate-filter collection pod fitted in place of the under-wing hose-drogue unit (HDU), allowing the aircraft to slip by undetected.

The final VC10 aerial refueling operations took place Sept. 20 with the last two K3 variants, ZA147 and ZA150. They took to the air and performed flybys over sentimental locations around the U.K. as part of the farewell. Days later, the aircraft made one-way flights to Dunsford, Surrey, and Bruntingthorpe, Leicestershire, to join museums and collections. AirTanker is now building up Voyager capability, and, on Aug. 11, was officially cleared to refuel the Eurofighter Typhoon.

The next major milestone for AirTanker and the RAF will be to clear the center-line HDU fitted to three-point Voyagers, allowing the aircraft to transfer fuel to larger receivers such as the C-130J Hercules and the Boeing E-3D Sentry. Trials with the two types are expected this year. This month, the company is due to take over the airbridge between the U.K. and the Falkland Islands, replacing civilian charter operators. A defensive aids suite upgrade is anticipated to allow the Voyager to begin flying between the U.K. and Camp Bastion, Afghanistan, before year-end.