From 1966, RAAF No 9 Squadron provided essential helicopter support, including troop transport and medical evacuations. They conducted hazardous resupply missions during battles. Despite sustaining casualties, the squadron’s operations remained vital to Australian forces until their departure in 1971.
After No 35 Squadron, the second Royal Australian Air Force (RAAF) service began on 3 May 1966, when an advance party from No 9 Squadron arrived at Vung Tau.
The squadron's helicopters arrived on 6 June aboard HMAS Sydney, and were flown to Vung Tau that day, then moved to Nui Dat at the end of the month.
No 9 Squadron's helicopters carried out a variety of roles in the former Republic of Vietnam (South Vietnam), including:
- transporting infantry
- providing logistic support
- dropping leaflets over enemy territory
- aerial spraying to rid the base of mosquitoes
- aerial spraying of vegetative growth around the base and on agricultural plots in Vietcong territory.
Just 2 months after the squadron's arrival, 2 pilots were called on to drop ammunition during the Battle of Long Tan. Flying in appalling weather at tree-top height, they dropped ammunition to the troops of D Company, 6th Battalion, The Royal Australian Regiment (6RAR). It was pouring with rain, and the helicopters were under intense Vietcong fire.
The squadron operated again that night, after the battle, to retrieve the wounded. They were guided only by the light emanating from the open hatches of armoured personnel carriers (APCs).
No 9 Squadron was re-equipped with larger Iroquois helicopters in 1967.
With 16 helicopters, the squadron worked in conjunction with the Royal Australian Navy Helicopter Flight Vietnam (RANHFV) and United States (US) forces. They took on the dangerous tasks of transporting men to and from patrols and evacuating wounded soldiers. Sometimes, these operations ended with the death of helicopter crewmen and the destruction of their aircraft.
The last members of 9 Squadron left Vung Tau on 17 December 1971. During operations, 6 Squadron members were killed, and another man was killed while attached to the squadron from the No 1 Operational Support Unit.