The first C-12A models entered service with the U.S. Army in 1974 and were used as a liaison and general personnel transport. The aircraft was essentially an "off-the-shelf" Super King Air 200, powered by the type's standard Pratt & Whitney Canada PT6A-41 engines.
The U.S. Navy followed suit in 1979, ordering a version of the Super King Air A200C (modified with a 1.32 m by 1.32 m; 52 inch by 52 inch cargo door from the Super King Air 200C), designating it the UC-12B, for logistics support between Naval and Marine Corps air stations, air facilities, and other activities, both in CONUS and overseas. The cabin can readily accommodate cargo, passengers or both. It is also equipped to accept litter patients in medical evacuation missions. Through 1982, the Navy ordered 64 of these aircraft.
A U.S. Air Force variant of the plane for surveillance roles primarily over Afghanistan and Iraq was the MC-12W Liberty. For that variant, Beechcraft built the basic plane and then sent it to Greenville, Texas where sophisticated intelligence, surveillance and reconnaissance (ISR) equipment was installed by L-3 Communications Missions Integration. As of 2013 the Liberty program had exceeded 300,000 combat flying hours. The MC-12W was rushed into combat as a supplemental surveillance and signals intelligence asset; since its first combat mission on 10 June 2009, the aircraft flew 400,000 combat hours in 79,000 combat sorties, aiding in the kill or capture of "more than 8,000 terrorists" and uncovering 650 weapons caches. With its roles taken over by the growing MQ-9 Reaper fleet, the Air Force decided to divest itself of the 41 Liberty aircraft and turn them over to the U.S. Army and U.S. Special Operations Command, which was completed by October 2015. The Air Force's final MC-12W deployment in support of Operation Enduring Freedom ended on 13 October 2015.
The TC-12B Huron was a twin-engine, pressurised version of the Beechcraft Super King Air 200. Twenty five served with the US Navy with training Squadron 35 (VT-35), the US Navy's only TC-12B Huron squadron based at Naval Air Station Corpus Christi, Texas, home of the Training Air Wing 4 (TAW-4). The US Navy retired this aircraft on 16 May 2017 and replaced and now relies on the T-44C for multi engine training.
Although the UD- series 1900s were manufactured exclusively for military use, the United States military and other military and government organizations use 1900s from other series such as the UB-series 1900C, and 1900Ds which may be found elsewhere.
King Air 200-based variants
U.S. Army C-12A
Used by the U.S. Army for liaison and attache transport. Based on the King Air A200 (serial numbers BC-1 through BC-61, BD-1 and up).
U.S. Navy single-aircraft version, UC-12B BuNo 161311 equipped with four P-3C type Sonobuoy launchers.
U.S. Navy training version developed by conversion of UC-12B airframes.
U.S. Army and U.S. Air Force version of the C-12A with upgraded engines. Based on the King Air A200 (serial numbers BC-62 and up).
U.S. Army and U.S. Air Force version. Based on the King Air A200CT, changes include larger cargo door, "high-flotation" landing gear (a Beechcraft option for larger main landing gear wheels for use on unimproved runways) (serial numbers BP-1, BP-22, BP-24 through BP-51).
U.S. Army version used for real-time tactical intelligence support under the Crazyhorse program. Based on the King Air A200CT (three aircraft, serial numbers FC-1 and up). Previously operated by U.S. Army Reserve aviation units.
Upgrade of earlier U.S. Army C-12F versions with improved cockpit instrumentation.
Upgrade of U.S. Army C-12T versions with improved cockpit instrumentation in order to meet global air traffic management directives.
Special mission, battlefield ELINT aircraft. Three A200s were brought by the U.S. Army for use in the Cefly Lancer program in the early 1970s.
Upgraded C-12R with Proline 21 FMS
King Air 300-based variants
MULTI-INT ISR platform. The MARSS provides the commander with a multi-intelligence collection capability to accurately detect, identify, and report threat targets in near real-time. IMINT, COMINT and ELINT intercept capability. As of June 2010, 11 MARSS were created from outfitted Beechcraft King Air B-300 aircraft.
King Air 350-based variants
U.S. Army version based on the King Air 350, with seating for 8 to 15 passengers and quick cargo conversion capability.
USAF version modified for the Intelligence, Surveillance & Reconnaissance (ISR) role; originally 8 King Air 350s and 29 King Air 350ERs and ending with 42 350ERs (including one combat loss). In service since June 2009 in Iraq and Afghanistan and globally for USSOCOM. All aircraft were transferred to USSOCOM, US Army, and other US government agencies by 2015. The Royal Canadian Air Force ordered 3 similar, if not, exact variants.
The following RC-12 variants, although similar to earlier RC-12's based on the KA-200, represent specially built airframes that combined upgraded engines (1,100 shp PT6A-67) and structural upgrades (swapping the traditional KA-200/300/350 T-Tail for the 1900 modified T-Tail to compensate for torque and aerodynamics and having reinforced spars to compensate for the increased maximum gross weight - up to as high as 16,500 lbs).
Intelligence-gathering platform. 14 ordered, the first delivered to the U.S. Army in January 2011.
Note: The U.S. military also operates other King Air versions under other designations, including the C-6 Ute and T-44 series. In addition, there are a number of Beechcraft 1900s operated by the military under civilian registrations, using their civilian model designations.