On 1 February 1964, HMM-364 replaced HMM-361 at Da Nang AB, together with its combat support missions HMM-364 was tasked with training VNAF personnel in helicopter operations as it was intended that they would be the last USMC helicopter unit deployed to Vietnam and would depart by 30 June. Following harassment attacks on the Marine compound, on 24 March a platoon from 1st Battalion 9th Marines was deployed to Da Nang AB to increase base security. By late May it had become clear that 30 June departure date was unrealistic and so in late June HMM-364 turned over their helicopters to the new VNAF 217th Squadron, HMM-162 returned to Da Nang. On 21 September the USMC evacuated Da Nang AB as Typhoon Tilda approached, the Marines returned to their damaged base on 23 September. On 29 September 1/9 Marines was replaced by a platoon from Company E 2nd Battalion 9th Marines. In early October HMM-162 was replaced by HMM-365. On 26 November E/2/9 Marines was replaced by the reinforced Company L 3rd Battalion 9th Marines.