In July 2015 Britain announced its was sending the second of its two new Airseeker electronics warfare aircraft to the Middle East to operate over Iraq and Syria to obtain more information about ISIL and pinpoint targets for air strikes. The first Airseeker arrived in the region earlier in 2015. This aircraft was delivered to Britain in early 2014. The second one arrives in August 2015 and is being sent to the Middle East before the end of the year. Both aircraft were ordered from the United States in 2010. Airseeker is what the Brits call their version of the American RC-135 "Rivet Joint" electronic warfare aircraft.
Britain bought Airseeker after concluding it was cheaper to buy a proven U.S. SIGINT (signals intelligence) electronic warfare aircraft than to develop a replacement for their elderly Cold War SIGINT aircraft. In 2010 this resulted in an order for RC-135s. These would be newly built, on old KC-135 tanker airframes. The U.S. Air Force already has 17 similarly constructed RC-135s, which have an excellent safety record. The U.S. agreed to deliver three RC-135 at three year intervals but managed to deliver ahead of schedule. Airseekers cost about $340 million each. There was opposition in Britain because the RC-135s would replace British designed and built electronic warfare aircraft. But the RAF pointed out that any other solution would take longer, the Americans had better and proven SIGINT equipment, and it was believed the electronic warfare aircraft were needed as soon as possible because of the fight against Islamic terrorists.
Britain found SIGINT aircraft very useful in Afghanistan, where their own electronic monitoring planes, based on their Nimrod maritime reconnaissance aircraft, operated for years. But the Nimrods were old and had developed problems that made them dangerous to fly. Britain felt that the best solution was to buy copies of the best available electronic warfare aircraft.
Costing about $4,000 an hour to operate, the RC-135s are popular and worked hard by the Americans, with one of them spending over 50,000 hours in the air since it entered service in 1962. The main reason for all those hours in the air is that RC-135s are very good at what they do and have been much in demand since September 11, 2001. The RC-135 is a flying vacuum cleaner of electronic signals. Built on the same airframe as the KC-135 tanker and Boeing 707 airliner, it carries two dozen people to operate all the electronic gear. Exactly what kind of electronic signals the RC-135 can pick up is classified but apparently includes any electronic device the enemy in Afghanistan is using.
RC-135s collect a wide variety of electronic signals in an area and analyze them quickly. The analysis effort is looking for patterns. Islamic terrorists down below leave signs electronically (cell phones, walkie-talkies) or visually (images captured on surveillance cameras). Using the right math and analytical tools (software and computers) you can quickly discover where the bad guys are coming from and have the ground troops promptly raid the location or air forces bomb it to bits.
This kind of work is popular with the RC-135 crews because they are getting a chance to do in a combat zone what they have long trained for. Moreover, it's relatively risk free, as the aircraft fly beyond the range of machine-gun or shoulder fired anti-aircraft missiles. In addition, the most productive work is done during night missions, when the bad guys can't even see the RC-135's high above. British crews for the Airseeker completed training in the U.S. by late 2013 and served in American RC-135s to gain experience. All that has been paying off over Iraq and Syria.