Clues emerge on the MC-12 SIGINT package
Speaking under condition of anonymity, officials working closely with the US Army’s Beechcraft MC-12W Liberty family of Signals Intelligence (SIGINT) gathering aircraft have provided some interesting insights into the capabilities of these aircraft which have been used extensively to support the US deployments in Afghanistan, Iraq and Syria.
The officials hinted that these aircraft have a SIGINT payload which is considered similar to that carried by the US Air Force’s Boeing RC-135V/W Rivet Joint family of SIGINT gathering platforms. They stated that these aircraft have “Rivet Joint-like” capabilities, albeit on a smaller-sized airframe. This could mean that the aircraft is capable of gathering communications intelligence across a three megahertz (MHz) to three gigahertz (GHz) range, and may also possess some capability to gather electronic intelligence pertaining to ground-based air surveillance and fire control radars possibly operating between circa 500MHz up to X-band (8.5GHz to 10.68GHz) and possibly above.
The official continued that the miniaturisation of such a payload which, in the case of the RC-135V/W is installed onboard a Boeing B-707 series turbofan transport brings “trade offs”; one of which is the aircraft’s field-of-view regarding hostile Radio Frequency (RF) emissions. As a basic rule of thumb, the higher a SIGINT platform flies, the larger its field-of-view regarding RF emitters on the ground. Given the 35,000 feet/ft (10,700m) ceiling of the Beechcraft Super King Air turboprop transport platform upon which the MC-12W is based, compared to the 50,000ft (15,200m) ceiling of the RC-135V/W family, the MC-12W’s RF field-of-view will be comparatively restricted, and is also more likely to place the aircraft in the threat envelope of short-range ground-based air defences, such as infra-red guided man-portable air defence systems, hence the MC-12W being more suited to operating in comparatively benign airspace.
That said, the concept of operations for an MC-12W platform could enable it to bring these Rivet Joint-like capabilities to the counter-insurgency fight, hence freeing up larger platforms such as the RC-135V/Ws to concentrate on their traditional mission of gathering operational-level SIGINT. This may explain why the Royal Air Force has established a mixed SIGINT fleet which consists of five (increasing to nine) Beechcraft Shadow-R1 aircraft, which is said to retain very similar capabilities to the MC-12W and its three RC-135W Airseeker platforms.