Upon arrival in South Vietnam the battalion, under Warr's command, commenced operations on 24 May 1966 by participating in the clearance of the 1 ATF base at Nui Dat – Operation Hardihood. For this operation the battalion was under the command of the US 173rd Airborne Brigade and worked alongside two American parachute battalions to clear the area out to mortar range, so that the base could be established. It was on this operation that the battalion's first soldier, Private Errol Noack, a 21-year-old from Adelaide, South Australia, was killed. Noack was critically wounded during a water resupply and died of his wounds at 36th Evacuation Hospital on 24 May 1966, sixteen days after he said farewell to his family. He was also the first National Serviceman to be killed in Vietnam.