When the 1st Marine Division sailed for Wonsan, both the Air Support and Air Defense sections of MTACS-2 sailed with them. Upon arrival at Wonsan, the Air Support section debarked on October 26, 1950, establishing the TADC on Wonsan Airfield, The Air Defense section moved to nearby Hamhung and was joined by the TADC on 6 November 1950. The Air Support section was with the 1st Marine Division from November 27 - December 10, 1950 during the Battle of Chosin Reservoir. They controlled the flow of aircraft in support of the division and also manned a portion of the western perimeter at Hagaru-ri where the Division Headquarters was located. A new innovation that was first utilized during the breakout from the Chosin Reservoir was the use of an Airborne Tactical Air Direction Center. Marines from MTACS-2 rigged additional radios into an R5D from VMR-152 and controlled close air support over the Marine column beginning on 7 December. Shortly after midnight on 15 December, MTACS-2 passed control of the airspace around Hungnam over to the Navy onboard "Mount McKinley".