Prior to the Vietnam War, the helicopter was a valued tool within the United States Army (USA) for aerial reconnaissance, airlift, medical evacuation (MEDEVAC) of wounded, and search and rescue (SAR).

[1] Helicopters within the USN were used for marine amphibious envelopment, search and rescue, vertical replenishment (VERTREP), and experimentally, as naval mine sweepers.

In 1965, the US Navy began joint operations off the southern coast of South Vietnam in support of the growing war.

In the same year, the Navy began limited Mobile Riverine Forces operations in the Mekong Delta, disrupting the Viet Cong's lines of communications, locating supply caches, and eliminating tax collecting stations.

It was also determined that key to the survival of the boats operating in the rivers would be close air support (CAS).

[3] Initially, the Brown-water Navy was supported by elements of the US Army's 145th Combat Aviation Battalion who had greater experience in helicopter gunship operations and tactics.

This, coupled with Army's pilots and aircrews lack of training in shipboard operations, identified a need for a dedicated, United States Navy, helicopter gunship program in Vietnam.

[3] In 1966, rotary wing support was originated as part of the response to the ongoing war in South Vietnam.

HC-1 operated two-aircraft detachments of Army UH-1B gunships, staged from shore bases and patrol craft tenders.

Encountering fierce resistance from them, the Navy boat commanders requested close air support.

Scrambling and arriving within approximately fifteen minutes, the Seawolves would claim 16 Viet Cong boats sunk or destroyed.

[9]: 126 After the activation of HA(L)-3 missions included aerial ambulance helicopter escort, aerial reconnaissance, airlift, air-sea rescue, airstrike, close air support, combat search and rescue, medical evacuation, search and destroy, special operations, and supporting SEAL Teams insertion and extraction.

Two ship formations would stand alert for 24-hour shifts and respond to close air support requests up to 50 miles (80 km) away from their base.

[10]: 2  On 23 April a helicopter from Detachment 3 hit a power cable and crashed at Cu Chi Base Camp killing one crewman.

[10]: 7 On 20 February Cambodian authorities returned the remains of two US Navy crewmen whose helicopter crashed in Cambodia on 28 April 1969.

[11]: 2  On 29 March Detachment 3 helicopters supported the defense of Chi Lang Special Forces Camp.