Week of September 24
On September 21, 1971, nearly 200 U.S. Air Force fighter and fighter-bomber aircraft launched an airstrike against three gasoline storage facilities just south of Đồng Hới, North Vietnam. Despite terrible weather, the strike was highly successful—U.S. pilots destroyed between 150,000 and 350,000 gallons of fuel without losing a single aircraft—thanks to Long-Range Aid to Navigation (LORAN) stations on the ground along the border. The mission was the first major airstrike in history to be conducted with LORAN technology, a significant advance in the history of air warfare.
First developed during and after World War II, LORAN technology worked by utilizing two or more transmission stations on the ground (or at sea) to send out a series of pulses. Specially equipped F-4 Phantom pathfinder aircraft then received these pulses. Based on the time differential between receptions of the two separate signals, a computer calculated the distance between the aircraft and each station, thus triangulating the aircraft’s position. LORAN systems could be accurate to within 100 yards and used signals that were impossible to corrupt. They also had the advantage of allowing strike aircraft to remain radio silent, increasing survival rates. The Air Force went on to use the technology extensively during the 1972 LINEBACKER raids. LORAN heralded a significant expansion of U.S. Air Force capabilities in poor-weather and nighttime missions. Today it has been largely replaced by far more precise satellite Global Positioning Systems.
The mission of September 21, 1971 took place under direct authorization from the White House, which ordered the commander of the Seventh Air Force, General John D. Lavelle, to conduct a major strike in North Vietnam. The White House constrained Lavelle, however, to targets within 20 miles of the Demilitarized Zone (DMZ). President Richard M. Nixon referred to this and earlier strikes in 1970 and 1971 as “protective reaction strikes.” It was later revealed that the administration used these strikes as negotiation tactics in ceasefire talks with North Vietnam. The White House ordered the strike of September 21, 1971, specifically as a response to the collapse of secret talks with Hà Nội’s Communist government, because North Vietnam refused to agree to a ceasefire and withdrawal unless the South Vietnamese government was dissolved.1
1Wayne Thompson, To Hanoi and Back: The United States Air Force and North Vietnam, 1966–1973 (Wash DC: Air Force History and Museums Program, 2000), 202–3; Spencer C. Tucker, ed., The Encyclopedia of the Vietnam War: A Political, Social, and Military History (2nd edition; Santa Barbara, Ca.: ABC-CLIO, 2011), 681; Carl Berger, ed., The United States Air Force in Southeast Asia, 1961–1973 (Wash DC: Office of Air Force History, 1977), 92; Ronald B. Frankum, Jr., Historical Dictionary of the Vietnam War (Lanham, Md., Scarecrow Press, 2011), 376.