These aircraft served in Latin America and then with the 138th Military Intelligence Company (Aerial Exploitation) in Orlando, Florida, before being moved into storage at Fort Sill, Oklahoma.

The initial system contractor ESL Inc. delivered 6 RC-12H in 1988 for the 3rd Military Intelligence Battalion at Camp Humphreys in Pyongtaek, South Korea.

The Guardrail Modernization program extends the life of the aircraft to 2025 and introduces new payloads to the system with enhanced capabilities.

The program enhances the sustainability of the RC-12X through commonality, a new glass cockpit, structural upgrades, and significant hardware and software improvements.

GR/CS uses a Guardrail Mission Operations Facility (MOF) for the control, data processing and message center for the system.”[6] On 16 April 1997, the 224th Military Intelligence Battalion lost an RC-12N and 2 crew members in a fatal training accident.

The following year on 6 November 1998, the 1st Military Intelligence Battalion lost a RC-12K and 2 crew members in a similar training accident.

In February 1999, Commanding General, USAIC and FH, Major General John D. Thomas, sent a senior standardization instructor pilot and the 305th Military Intelligence Battalion Safety Officer to USAAVNC to review the RC-12K Accident Board findings to determine if training was a contributing factor.

They recommended to Major General Thomas that the TC 1-219, Tasks for Slow Flight, Stalls and VMC, be rewritten.