The UK’s Secretary of Defense, Bob Ainsworth, confirmed on March 22 that the Royal Air Force would receive three Boeing RC-135 Rivet Joint aircraft to provide its signals intelligence (Sigint) gathering capability, the final agreement having been reached on March 19. The announcement brought to an end any lingering speculation concerning the immediate future of RAF Sigint.

Currently, the RAF’s No. 51 Squadron operates a pair of Nimrod R1 aircraft in the role, having retired one airframe last year. To provide ongoing Sigint capability, the UK Ministry of Defense instigated Project Helix, which initially focused on a major upgrading of the R1’s capabilities. When airframe issues ruled out further upgrades, Helix was widened to examine other alternatives. Possibilities included a Nimrod “R5” based on the new-generation Nimrod MRA4, or various airliner-based options. Ultimately,
Rivet Joint was chosen as “the only viable option that meets the requirements of our armed forces,” according to Ainsworth.

To be modified from surplus KC-135 tanker airframes, the UK’s three Rivet Joints are scheduled to enter service in 2014. Following on from the withdrawal of the RAF’s Nimrod MR2 ASW patrol fleet on March 31, the two R1 Elint aircraft are due to be retired in March next year, leaving a capability gap. This is expected to be filled by the borrowing or joint operation of U.S. Air Force Rivet Joints until the RAF’s own RC-135s enter service.