U.S. NATIONAL SECURITY AGENCY NON-RECORD COPIES OF HELICOPTER RADIO MESSAGES DURING EVACUATION OF U.S. EMBASSY IN SAIGON, 4/29-30/1975

In his letter donating this collection to the Gerald R. Ford Library, Lt. Gen. Kenneth A. Minihan, Director, National Security Agency, described the materials as follows: “The enclosed file represents messages pertaining to the evacuation of Saigon, 29 and 30 April 1975. As a classified file, it was in the possession of an NSA analyst since the evacuation, and only recently came into the Center for Cryptologic History. It is no longer considered sensitive, and we have secured authorization from the Office of the Secretary of Defense for its declassification and release. In view of the importance of the evacuation to the history of the Ford Administration, it is appropriate that the file be turned over to the Ford Library for dispostion.”

He continued, “When the evacuation plan was written, one of the SIGINT collection units in Southeast Asia was tasked with intercepting U.S. communications and forwarding copies to U.S. command and control authorities in Hawaii and Washington. This organization collected communications from the EC-130 Airborne Battlefield Command and Control Center (ABCCC), as it relayed communications to and from the helicopters ferrying evacuees from the DAO [Defense Attache Office] compound at Tan Son Nhut, and from the American Embassy, to the U.S. fleet off-shore. The enclosed messages are verbatim transcripts of transmissions from that command post, commonly referred to by its covername, Cricket.”

“Although the helicopter evacuation began about 1400 Saigon time on 29 April, this file of messages does not begin until 1602 local. (Note that the time following each message is in Zulu time, which is eight hours behind Saigon time.) This probably accounts for the fact that, though 236 messages were passed, this file contains only 216. The evacuation’s conclusion, and the last transmission in the file, were at 0751 Saigon time (2351Z). At that time the Marine ground security force was on the last helicopter and the embassy was abandoned to the remaining Vietnamese.”

The messages are very cryptic and replete with military jargon making them most useful to researchers who already have a full grasp of the events, but to such a reader they provide drama and immediacy rarely found in historical documents.

The transcriptions have been divided into folders by hours with titles being given in Washington,D.C. and Saigon time to assist researchers wishing to place these messages in context with other documents using non-military times.

Related Materials (April 1999)
National Security Adviser: Files (1969) 1974-77, particularly NSC Staff, Convenience file of communications with the U.S. Embassy in Saigon, (1963) 1970-75 (1976).