In the spring of 1965, within weeks of 3,500 American Marines arriving in Vietnam, a 39-year-old Briton named Larry Burrows began work on a feature for LIFE magazine, chronicling the day-to-day experience of U.S. troops on the ground – and in the air – in the midst of the rapidly widening war. The photographs in this gallery focus on a calamitous March 31, 1965, helicopter mission; Burrows’ “report from Da Nang”, featuring his pictures and his personal account of the harrowing operation, was published two weeks later as a now-famous cover story in the April 16, 1965, issue of LIFE.

Photo: Man your battle stations: The crew chief of helicopter Yankee Papa 13, lance corporal James C. Farley, mans an M-60 machine gun during a mission near Da Nang, Vietnam on March 31, 1965. (Photo by Larry Burrows/Time & Life Pictures)

A chevrotain or mouse deer feeds in its enclosure at Zurich Zoo, Zurich, Switzerland, October 17, 2012. (Photo by Patrick B. Kraemer/AP)

Carey Williams leaps into the icy waters of the Snake River for the 2022 Polar Plunge at the Hells Gate Marina on Saturday, January 1, 2022, in Clarkston, Wash. (Photo by August Frank/Lewiston Tribune via AP Photo)

Baltimore Orioles center fielder Austin Hays leaps while taking the field prior to the first inning of a baseball game against the Cleveland Guardians, Tuesday, May 30, 2023, in Baltimore. (Photo by Julio Cortez/AP Photo)

Michael Cimino, Amanda Diaz and Xochitl Gomez attend the world premiere of “The Flash”, in Hollywood, Los Angeles, California, U.S., June 12, 2023. (Photo by Mike Blake/Reuters)

People take pictures near a Soviet flag flying on an embankment in Saint Petersburg, Russia on June 17, 2023. The flags of Russia, the USSR, and the Russian Empire were installed on the shore to mark the anniversaries of each flag's adoption. (Photo by Anton Vaganov/Reuters)

Jamaica's Tissanna Hickling competes in the women's long jump qualification during the World Athletics Championships at the National Athletics Centre in Budapest on August 19, 2023. (Photo by Kirill Kudryavtsev/AFP Photo)

A female soldier takes part in a training for women at the Tolemaida Military Air Base in Tolemaida, Colombia, on May 16, 2023. The last time the Colombian Army enlisted women in their ranks was in 1993. Now, 30 years on, more than 1,200 women voluntarily joined the military service in the country. (Photo by Raúl Arboleda/AFP Photo)