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 model showcases lingerie during a lingerie show on International Women's Day at a shopping mall on March 8, 2011 in Qingdao, Shandong Province of China. The official theme of International Women's Day 2011 is “Equal access to education, training and science and technology: Pathway to decent work for women”. (Photo by ChinaFotoPress/Getty Images). QINGDAO, CHINA – MARCH 08 2011

A model backstage during day 1 of Aspen Fashion Week 2011 on March 13, 2011 in Aspen, Colorado.

A model prepares backstage ahead of the Amber & Thomas show during Rosemount Australian Fashion Week Spring/Summer 2011/12 at Overseas Passenger Terminal on May 3, 2011 in Sydney, Australia. (Photo by Ryan Pierse/Getty Images)

Daisy Lowe attends The Phillips British Academy Awards 2011 at The Grosvenor House Hotel on May 22, 2011 in London, England. (Photo by Dave Hogan/Getty Images)

Kaci Nuyen 8, holds a “Kiddizoom Twist” camera during a Hamleys Christmas toy photocall at Hamleys Toy store on June 28, 2011 in London, England. The famous toy store unveiled today their “must have” toys for Christmas 2011. (Photo by Dan Kitwood/Getty Images)

Sunrise over Haleakala Crater, Haleakala National Park, Maui, Hawaii on April 26th, 2011. (Photo by Robert Bush/Alamy Stock Photo)