Operation Frequent Wind was the final phase in the evacuation of American civilians and "at-risk" Vietnamese from Saigon, South Vietnam, before the takeover of the city by the North Vietnamese People's Army of Vietnam (PAVN) in the Fall of Saigon. It was carried out on 29–30 April 1975, during the last days of the Vietnam War. More than 7,000 people were evacuated by helicopter from various points in Saigon. The airlift resulted in several enduring images.
Evacuation plans already existed as a standard procedure for American embassies. At the beginning of March, fixed-wing aircraft began evacuating civilians from Tan Son Nhat Airport through neighboring countries. By mid-April, contingency plans were in place and preparations were underway for a possible helicopter evacuation. As the imminent collapse of Saigon became evident, the U.S. Navy assembled Task Force 76 off the coast near Vũng Tàu to support a helicopter evacuation and provide air support if required. In the event, air support was not needed as the North Vietnamese paused for a week at the outskirts of Saigon, possibly waiting for the South Vietnamese government to collapse and avoiding a confrontation with the U.S. by allowing the mostly-unopposed evacuation of Americans from Saigon.
On 28 April, Tan Son Nhut Air Base (next to the airport) came under artillery fire and attack from Vietnamese People's Air Force aircraft. The fixed-wing evacuation was terminated and Operation Frequent Wind began. During the fixed-wing evacuation 50,493 people (including 2,678 Vietnamese orphans) were evacuated from Tan Son Nhut. The evacuation took place primarily from the Defense Attaché Office compound, beginning around 14:00 on 29 April, and ending that night with only limited small arms damage to the helicopters. The U.S. Embassy in Saigon was intended to be only a secondary evacuation point for embassy staff, but it was soon overwhelmed with evacuees and desperate South Vietnamese. The evacuation of the embassy was completed at 07:53 on 30 April, but some Americans chose to stay or were left behind and some 400 third-country nationals were left at the embassy.
Tens of thousands of Vietnamese evacuated themselves by sea or air. With the collapse of South Vietnam, numerous boats and ships, Republic of Vietnam Air Force (RVNAF) helicopters and some fixed-wing aircraft sailed or flew out to the evacuation fleet. Helicopters began to clog ship decks and eventually, some were pushed overboard to allow others to land. Pilots of other helicopters were told to drop off their passengers and then take off and ditch in the sea, from where they would be rescued. In Operation Frequent Wind a total of 1,373 Americans and 5,595 Vietnamese and third-country nationals were evacuated by helicopter. The total number of Vietnamese evacuated by Frequent Wind or self-evacuated and ending up in the custody of the United States for processing as refugees to enter the United States totalled 138,869.
Planning for the evacuation of the Americans and their South Vietnamese allies from South Vietnam had begun before April 1975. When U.S. President Gerald Ford met with the National Security Council on 9 April 1975 he was told by Henry Kissinger that a maximum of 1.7 million people had been identified as possible evacuees and that these included: American citizens and their relatives, the diplomatic corps, the International Commission of Control and Supervision (ICCS), third-country nationals under contract by the U.S. government and the employees of the U.S. and their dependents (estimated at 200,000 people). In addition, the Vietnamese relatives of American citizens and senior Government of Vietnam officials and their dependents (about 600,000 people) were also identified as potential evacuees, along with Vietnamese formerly employed by the U.S. and their dependents.
Although American officials at the highest levels of the intelligence community (e.g. CIA Director William Colby) were certain that the South Vietnamese government would collapse, the U.S. government underestimated the speed of the North Vietnamese advance during the 1975 Spring Offensive and how quickly the Army of the Republic of Vietnam (ARVN) would collapse.
Evacuation plans are standard for American embassies. The Saigon plan had been developed over several years. Originally codenamed "Talon Vise", the operation was renamed "Frequent Wind" when the original codename was compromised.
By 1975, the Frequent Wind plan aimed to evacuate about 8,000 U.S. citizens and third-country nationals, but it was never able to estimate the number of South Vietnamese to include. There were about 17,000 at-risk Vietnamese on embassy rolls, which, using an average of seven dependents per family, meant that the number requiring evacuation was 119,000. Taken with other categories of Vietnamese, the number quickly passed 200,000. The Frequent Wind plan set out four possible evacuation options:
Option 1: Evacuation by commercial airlift from Tan Son Nhut and other South Vietnamese airports as required
Option 2: Evacuation by military airlift from Tan Son Nhut and other South Vietnamese airports as required
Option 3: Evacuation by sea lift from Saigon port
Option 4: Evacuation by helicopter to US Navy ships in the South China Sea
With Option 4, the helicopter evacuation would be expected to be similar to Operation Eagle Pull, the American evacuation by air of Phnom Penh, Cambodia, on 12 April 1975.
On 1 April an evacuation control center manned by U.S. Army, U.S. Navy, U.S. Air Force (USAF) and U.S. Marine Corps (USMC) personnel began operating at the Defense Attaché Office (DAO) compound on 12-hour shifts, increasing to 24-hour shifts the next day. Also on 1 April, Plan Alamo was implemented to defend the DAO compound and its annex so it could serve as a holding area for 1,500 evacuees for five days. By 16 April, Alamo was complete: water, C-rations, petroleum, oil, and lubricants had been stockpiled; backup electricity generators had been installed; sanitary facilities were completed; and concertina wire protected the perimeter.
On 7 April Air America pilot Nikki A. Fillipi, with U.S. Marine Corps Lieutenant Robert Twigger, assigned to the DAO as the U.S. Navy liaison officer, surveyed 37 buildings in Saigon as possible landing zones (LZ), selecting 13 of them as fit for use. Workers from Pacific Architects and Engineers visited each of the 13 LZs to remove obstructions and paint 'H's the size of a UH-1 Huey helicopter's skids. President Ford, in an address to the American public on 11 April, promised to evacuate Vietnamese civilians of various categories. The 9th Marine Amphibious Brigade (9th MAB), which was to supply helicopters and a security force for the evacuation, sent a delegation to consult with Ambassador Graham Martin on current plans on 12 April. Martin told them that he would not tolerate any outward signs that the United States intended to abandon South Vietnam. All planning would have to be conducted with the utmost discretion. Brigadier General Richard E. Carey, commander of the 9th MAB, flew to Saigon the next day to see Martin; he later said, "The visit was cold, non-productive and appeared to be an irritant to the Ambassador". Thirteen Marines from the Marine Security Guard (MSG) detachment were deployed to the DAO Compound on 13 April to replace eight Marine guards who had been providing security after they were withdrawn from the closed Da Nang and Nha Trang consulates.
By late April, Air America helicopters were flying several daily shuttles from TF76 to the DAO Compound to enable the 9th MAB to conduct evacuation preparations at the DAO without exceeding the Paris Peace Accords' limit of 50 U.S. military personnel in South Vietnam. The U.S. government was continuing to observe its obligations under the Accords, notwithstanding the North Vietnamese invasion. In late April, the MSG Marines were ordered to abandon Marshall Hall/Marine House, their billet at 204 Hong Thap Tu Street (now 204 Nguyen Thi Minh Khai Street), and move into the recreation area in the embassy compound.