Britain is withdrawing all of its Nimrod reconnaissance aircraft from overseas, until all can have problems with fuel leaks and air circulation fixed. This is a major problem in Afghanistan, where the Nimrods have been very useful in providing ground surveillance and electronic monitoring. It was hoped some Nimrods could be kept in service overseas, but the need for repairs proved more urgent than expected.
The main cause of the problems is age related. The Nimrod is a 1960s design that uses the airframe of the 1950s era Comet airliner. There has been work on a replacement aircraft, but money shortages, and disagreements over specifications, have delayed this.
Crews have complained about the problems for years. The repair program was largely motivated by a Nimrod crash in Afghanistan in 2006, because of fuel leak problems, and the remaining 18 Nimrods are considered too old to be fixed by anything short of a complete rebuild. This is underway, but the first rebuilt Nimrod won't be available until next year.
Three of the Nimrods are the R1 variant, and used as signals intelligence aircraft, and are considered essential over Afghanistan. Britain needs the electronic monitoring aircraft now. So they leased two U.S. Air Force electronic monitoring aircraft (RC-135 Rivet Joint) to fill in because of shortages. The aircraft will have joint British and American crews, but will be painted in Royal Air Force colors. Britain is also buying three RC-135s from the United States, at $350 million each. Most of this money is for the electronics. The aircraft itself is a rebuilt KC-135 tanker.