 The Nimrod fleet was retired in 2011, the RAF co-manned aircraft of the US Air Force until the three RC-135s entered service between 2014 and 2017.The aircraft were Boeing KC-135R Stratotanker tankers converted to RC-135W standard in the most complex combined Foreign Military Sales case and co-operative support arrangement that the UK had undertaken with the United States Air Force since the Second World War.Airseeker received its first operational deployment in August 2014, when it was deployed to the Middle East to fly missions over Iraq and Syria as part of Operation Shader.