Delivery to the UK of a new SIGINT aircraft for the Royal Air Force has been postponed. The UK’s Military Airworthiness Authority (MAA) has not yet reviewed the safety case. The Airseeker (the RAF’s name for the U.S. Air Force RC-135 Rivet Joint system) is the latest airframe that could be delayed by the MAA’s detailed scrutiny, which British defense contractors have privately called overzealous. Others have included the Beechcraft Super King Air 350ERs acquired by the Royal Navy for observer training; the Airbus A330MRTTs entering RAF service as a refueling tanker; and the Thales Watchkeeper UAV for the British Army.

The U.S. Air Force declared the first Airseeker ready for delivery in mid-October, six months ahead of schedule, a U.S. official with detailed knowledge of the acquisition told AIN. Like the 17-strong USAF fleet of Rivet Joints, it has been converted from a Boeing KC-135 by L-3 Communications at its Greenville, Texas facility. The process has taken nearly three years. The UK has allocated £633 million (just over $1 billion) to acquire three aircraft at two-year intervals, plus their associated ground stations. They are replacing three already-retired SIGINT versions of the Nimrod maritime patrol aircraft.

In the meantime, RAF aircrews have joined the USAF’s Rivet Joint squadrons in a co-manning operation. The U.S. official praised the contribution of the newly trained British crews. He also noted that the UK had been given “unprecedented and total” access to the highly classified SIGINT systems on the Rivet Joint. A senior RAF officer last year described the acquisition of the Airseeker as “a fantastic opportunity for greater strategic understanding.”

The MAA was set up after the crash of an RAF Nimrod over Afghanistan in 2006 and a subsequent review that criticized the MoD's safety oversight. Commenting on the certification of the Airseeker in its last annual report, the MAA noted that “the archaic heritage of the basic design...has the potential to be particularly challenging.” The three RAF aircraft are being converted from the last KC-135s to be built. However, even these airframes are 50 years old.

The UK Ministry of Defence (MoD) told AIN that a three-month review of the available technical evidence in early 2012 had identified “some gaps in evidence.” The UK’s Defence Equipment and Support (DE&S) acquisition organization had contracted QinetiQ to help in building a robust safety case. The U.S. official told AIN that the USAF had tired of answering the stream of questions from QinetiQ and was now referring them to Boeing, as the OEM. The MoD confirmed to AIN that DE&S had sought additional information on “a number of aircraft systems.”

The MoD told AIN that the DE&S aimed “to have the necessary evidence in place in spring 2014 to support the aircraft receiving its approval to fly to allow workup to IOC (initial operating capability) later in the year.” That milestone is officially scheduled for next October. The USAF itself evidently has complete faith in the ability of L-3 Communications to strip down, overhaul and convert the RC-135 airframes; it intends to operate the Rivet Joint fleet until 2042.