It may be three years behind schedule, but the U.K.'s long-running WK450 Watchkeeper unmanned air system (UAS) could now be on the cusp of entering service.

The system built by Thales U.K. has been held back by dramatic changes in the way the U.K. Defense Ministry brings new aircraft into service. But despite this, there is optimism that the certification process used by the U.K.'s Military Aviation Authority (MAA) could ultimately allow wider uses for the aircraft once it is operational with the British Army.

Watchkeeper was initially scheduled to enter service in September 2010. The timing of its introduction to testing coincided with the backlash from the 2006 Nimrod patrol aircraft crash in Afghanistan, when the resulting Haddon-Cave report's recommendations were finally being implemented. The overhaul in the safety culture and oversight of military air safety culminated in the formation of the MAA in April 2010.

The new regulations formed by the MAA have slowed several procurement programs, but the process has been particularly painful for Watchkeeper, as MAA personnel have little or no experience in certifying UAS. The Royal Air Force's General Atomics MQ-9 Reaper and the Hermes 450 system, code-named Lydian, being used by the British Army in Afghanistan as a gap-filler, skirted the process by being procured through the urgent operational requirements system. But the British Army wants to fly Watchkeeper in U.K. airspace to support training, so it has essentially become the pilot program for certification of military UAS in the U.K.

Thales says it received from the MAA a Statement of Type Design Assurance (STDA), which confirms that the system has reached “an acceptable level for design safety and integrity” to meet the current stage of its development. The system cannot be used by the British Army, however, until it is given a Release to Service (RTS) certification, which Thales hopes will be achieved by year-end.

The STDA for Watchkeeper is the result of a tailored Military Air Systems Certification Process (MACP), rather than a military type certificate, because the system was already in certification testing when the MACP process was officially introduced on April 1, 2012. No UAS has yet gone through the full MACP.

Nonetheless, Thales U.K. says the certification represents a “major step forward” for the acceptance of UAS in the airspace environment and that it “underpins military flying globally in appropriate airspace.”

The Watchkeeper test fleet has flown more than 1,000 hr. over 600 flights. All flight testing is being carried out at the UAS test range in Aberporth, Wales. Once the MAA has certified the aircraft and signed off its RTS, Watchkeeper may begin flights over the Salisbury Plain Training Area in southern England. It should be able to support Royal Artillery training there from the Qinetiq-operated Boscombe Down airfield, where the UAV is likely to mix in airspace with military manned traffic.

Army pilots have been able to train on the system with Thales test pilots through a military flight-test permit.

The UAS will also be the focus of an upcoming trial in conjunction with the U.K. National Air Traffic Services, which has been funded by the Single European Skies (Sesar) air traffic management program to conduct UAS flights in controlled airspace. Simulations in April 2014, with trials following in the summer, could pave the way for the system's use in civil protection missions such as search and rescue.

Thales and the army have been keen to explore those civil missions to make wider use of Watchkeeper. Civil Aviation Authority UAS rules stipulate that platforms must have a sense-and-avoid system to operate in mixed airspace.

Watchkeeper's costs have grown to £831 million ($1.3 billion) from the initial £700 million, and the program was on a list of projects considered potentially untenable or needing to be “rescoped.”

Thales officials say the work on Watchkeeper has “pipe-cleaned” the MAA's process for introducing unmanned systems and established a path for others to follow, but it is unclear if the system will find its way into operations in Afghanistan.