The UK Royal Air Force flies three Nimrod R.1 versions that are dedicated to SIGINT (signals intelligence). They were converted from MR.2 maritime patrol aircraft, and their sensors have been upgraded regularly to monitor emerging new threats and signals. The UK Ministry of Defence (MoD) developed a plan for a complete replacement of the aircraft’s SIGINT suite, Project Helix, and chose L-3 Communications UK to provide it. But after the fatal crash of a Nimrod MR.2 in Afghanistan in September 2006, aging airframe issues surrounding those aircraft became controversial. BAE Systems told AIN recently that supporting the three unique R.1 aircraft in future years “could be very expensive.”

The MoD therefore sought alternatives. It explored joining the U.S. Air Force RC-135 Rivet Joint SIGINT operation, in similar fashion to the Joint Predator Task Force that was set up in 2004, so that RAF pilots and ground crew could operate alongside U.S. Air Force UAV crews. But some British insiders in the SIGINT community criticized that option, citing a possible loss of control and operational sovereignty over this sensitive and vital mission.

Now AIN understands that the U.S. Department of Defense has selected three USAF KC-135R airframes for a possible foreign military sale sale to the UK. They would be converted to an RC-135 SIGINT configuration by L-3 Communications Integrated Systems in Greenville, Texas. Meanwhile, L-3 Communications UK told AIN that its design for the Helix electronic reconnaissance system was “platform agnostic” and suitable for carriage on whatever medium-size aircraft the MoD chooses. In theory, the system could be carried on the new MRA.4 version of the Nimrod that BAE Systems is building to replace the MR.2 for the RAF. But the option of developing an “R.5” version incorporating the Helix system does not appear to have received serious consideration, possibly because BAE Systems would charge too much to do the conversion.