The C-12 Huron is the military designation for a series of twin-engine turboprop aircraft based on theBeechcraft Super King Air and Beechcraft 1900. C-12 variants are used by the United States Air Force, United States Army, United States Navy and United States Marine Corps. These aircraft are used for various duties, including embassy support, medical evacuation, as well as passenger and light cargo transport. Some aircraft are modified with surveillance systems for various missions, including the Cefly Lancer, Guardrail and Project Liberty programs.

Design and development
The first C-12A models entered service with the U.S. Army in 1974 and was 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 standardPratt & 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 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 is the MC-12 Liberty. For that variant, Beechcraft builds the basic plane and then sends it to Greenville, Texas where sophisticated Intelligence, Surveillance & Reconnaissance equipment is installed by L-3 Communications Missions Integration.

C-12J
To meet the needs of transporting larger groups, the U.S. Army purchased six C-12J aircraft, based on the Beechcraft 1900C commuter airliner. One of the military C-12Js is used for GPS jamming tests at the 586th Flight Test Squadron, Holloman Air Force Base, New Mexico. Another is based at the 517th Airlift Squadron, Elmendorf Air Force Base, Alaska. Three were based at the 55th Airlift Flight, Osan Air Base, South Korea. They have been relocated to the 459th Airlift Squadron, Yokota Air Base, Japan. The remaining two are used by U.S. Army Aviation.

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.

Variants
King Air 200-based variants
C-12A
Used by the US Army for liaison and attache transport. Based on the King Air A200 (serial numbers BC-1 through BC-61, BD-1 and up).

UC-12B
US Navy/US Marine Corps version with an additional cargo door. Based on the King Air A200C (serial numbers BJ-1 and up).

NC-12B
US Navy single-aircraft version, UC-12B BuNo 161311 equipped with four P-3C type Sonobuoy launchers.

TC-12B
US Navy training version developed by conversion of UC-12B airframes.

C-12C
US Army and US Air Force version of the C-12A with upgraded engines. Based on the King Air A200 (serial numbers BC-62 and up).

C-12D
US Army and US 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).

RC-12D
Special mission, SIGINT aircraft for the US Army.

UC-12D
Based on the King Air A200CT (serial numbers BP-7 though BP-11).

C-12E
Upgraded C-12A aircraft for the USAF. 29 C-12As were retro-fitted with two Pratt & Whitney Canada PT6A-42 turboprop engines.

C-12F
US Air Force transport version. Based on the King Air A200CF (serial numbers BP-52 through BP-63) and the King Air B200C (serial numbers BP-64 and up).

RC-12F
US Navy version of the UC-12F modified with surface search radar.

UC-12F
US Navy version based on the King Air B200C (serial number BU-1 and up, BV-1 and up, BW-1 and up).

RC-12G
US 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 US Army Reserve aviation units.

RC-12H
Special mission, battlefield SIGINT aircraft for the US Army.

C-12L
Three A200s acquired for use in the Cefly Lancer program as RU-21Js. In 1984 the three aircraft modified with new VIP interiors, and returned to the US Army as C-12Ls.

UC-12M
US Navy UC-12B and UC-12F aircraft with upgraded cockpit instrumentation.

RC-12M
US Navy RC-12F with upgraded cockpit instrumentation, plus other systems and structural upgrades.

C-12R
Off the shelf BE200 modified with EFIS glass cockpit instrumentation.

C-12T
Upgrade of earlier US Army C-12F versions with improved cockpit instrumentation.

C-12U
Upgrade of US Army C-12T versions with improved cockpit instrumentation in order to meet global air traffic management directives.

RU-21J
Special mission, battlefield ELINT aircraft. Three A200s were brought by the US Army for use in the Cefly Lancer program in the early 1970s.
RC-12X

Intelligence-gathering platform. 14 ordered, the first delivered to the US Army in January 2011.

King Air 350-based variants
C-12S
US Army version based on the King Air 350, with seating for 8 to 15 passengers and quick cargo conversion capability.

MC-12W Liberty
USAF version modified for the Intelligence, Surveillance & Reconnaissance (ISR) role; 8 King Air 350s and 29 King Air 350ERs. In service since June 2009 in Iraq and Afghanistan.

UC-12W
US Navy version based on the King Air 350
Beechcraft 1900-based variant

C-12J
Used by the US Air Force's Pacific Air Forces, and Air Force Materiel Command. It carries 2 crew and 19 passengers. The C-12J is based on the Beechcraft 1900C and carries the serials UD-1 through UD-6.

The Air Force currently operates only 4 C-12Js. 3 are operated by the 459th Airlift Squadron at Yokota Air Base, Japan and 1 by the Air Force Materiel Command from Holloman AFB, New Mexico. The Army has 2 C-12Js in use, 1 in Korea and 1 in Germany.

Note: The U.S. military also operates other King Air versions under other designations, including the C-6 Ute and T-44series. In addition, there are a number of Beechcraft 1900s operated by the military under civilian registrations, using their civilian model designations.
 
C-12V
Upgraded C-12R with Proline 21 FMS, currently used exclusively in Iraq and Afghanistan