CAMP HUMPHREYS, Korea — The 501st Military Intelligence Brigade-Theater (MIB-T) observed the closure of the U.S. Army’s two most distinguished aerial intelligence, surveillance and reconnaissance (ISR) legacies, GUARDRAIL and Airborne Reconnaissance Low (ARL) during events, July 30-31, 2025.
In an event designated Operation PACIFIC SUNSET, the 501st MIB-T hosted a commemorative ceremony at the Desidario Army Airfield that featured a final flight of the aerial platforms, exhibition flights, and a runway display of aircraft. Soldiers of the Republic of Korea concluded the ceremony with a dedication honoring the contributions of the 3rd Military Intelligence (MI) Battalion, ARL, and GUARDRAIL Common Sensor (GRCS).
Since 1975, GUARDRAIL has provided indications and warnings to United States