In 1967 No. 9 Squadron was operating in direct support of the 1st Australian Task Force at Nui Dat. Late that year the squadron was re-equipped with larger Iroquois helicopters than those with which it had previously operated and its strength doubled to sixteen aircraft. Already heavily committed in Vietnam, Malaysia and at home, the RAAF was short of trained aircrew. The RAN was approached to help temporarily by providing pilots, eight of whom joined the squadron in 1968. As well as the RAN detachment, thirteen Royal New Zealand Air Force pilots also flew with 9 Squadron.
Flying with RAAF aircrews, RAN pilots provided covering fire for MEDEVAC aircraft and were sometimes asked to evacuate wounded soldiers in their single-stretcher helicopters. They escorted gunships in combat assaults and retrieved Special Air Service (SAS) patrols from enemy occupied areas, often performing 'hot extractions' when they were in contact with the enemy.
The squadron also conducted 'people sniffer' missions in a specially equipped helicopter fitted with sensors. As the helicopter flew low over the jungle canopy, the sensors would analyse air samples, detecting concentrations of carbon dioxide (CO2) gas. This would supposedly indicate a concentration of people or CO2 coming from air vents in underground enemy bunkers in the area.
The RAN detachment remained in Vietnam until March-April 1969, enabling the RAAF to consolidate its pilot training program for Vietnam. Many of the RAN pilots also flew missions with the RAN Helicopter Flight (RANHFV) during their time in Vietnam.