A Thorneycroft motor van as used during World War I. (Photo by Topical Press Agency/Getty Images). August 1914

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)

“G.I. Joe is a line of action figures produced by the toy company Hasbro. The term G.I. stands, in popular usage, for Government Issued and after the First World War became a generic term for U.S. soldiers. The origin of the term dates to World War I, when much of the equipment issued to U.S. soldiers was stamped “G.I.”, meaning that it was made from galvanized iron. The development of G.I. Joe led to the coining of the term “action figure”. G.I. Joe's appeal to children has made it an American icon among toys”. – Wikipedia. Photo: Vintage G.I. Joe figurers are on display at the 2003 Hasbro International G.I. Joe Collectors' Convention June 27, 2003 in Burlingame, California. (Photo by Justin Sullivan/Getty Images)

A fan watches the group A World Cup match between Mexico and Brazil via a live broadcast at the FIFA Fan Fest in Sao Paulo, Brazil, Tuesday, June 17, 2014. Forget the French manicure. It’s Brazil during World Cup, and women here want to flaunt their love of the national team with wacky nail designs. (Photo by Dario Lopez-Mills/AP Photo)

Ghanaian fans take a selfie prior to a Group G football match between Germany and Ghana at the Castelao Stadium in Fortaleza during the 2014 FIFA World Cup on June 21, 2014. (Photo by Patrik Stollarz/AFP Photo)

Harry Potter collectible busts are displayed in the home of Menahem Asher Silva Vargas, after he was presented with a Guinness World Record title certificate for the largest collection of Harry Potter memorabilia, in Mexico City, Monday, September 29, 2014. Silva's collection consists of more than 3000 individual items, including trading cards, wands, and books in multiple languages. (Photo by Rebecca Blackwell/AP Photo)

Miss World 2013, Megan Young of the Philippines, poses during a publicity launch near to Big Ben and the Houses of Parliament in central London November 25, 2014. The final of the 2014 edition of the pageant will take place in London on December 14. (Photo by Toby Melville/Reuters)