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 man, right, throws a chair at a business window as another man tries to restrain a woman attempting to stop the damage, after march to City Hall for Freddie Gray, Saturday, April 25, 2015 in Baltimore. Gray died from spinal injuries about a week after he was arrested and transported in a police van. (Photo by Alex Brandon/AP Photo)

A woman looks for fruits to buy inside a bus called Sacolao in Santa Teresa neighborhood in Rio de Janeiro, Brazil, July 7, 2015. The bus, which began operating as a municipal initiative but has been taken over by a private enterprise, arrives every week in some neighborhoods to facilitate families with their grocery shopping and sells food at an affordable price, according to sellers. (Photo by Pilar Olivares/Reuters)

Customers take photos of a snake at the Tokyo Snake Center, a snake cafe, in Tokyo's Harajuku shopping district August 14, 2015. The cafe has on display 35 non-venomous snakes of 20 different breeds. Open six days a week, the cafe allows customers to enjoy food and beverages while watching a small snake slither around in a cage on their table for a 1,000 yen (8.04 dollars). By paying an additional fee, customers get to hold and pet the snake. (Photo by Toru Hanai/Reuters)

Thai classical dancers perform for Phra Phrom, the Thai interpretation of the Hindu god Brahma, at the Erawan Shrine in Bangkok, Thailand, Friday, September 4, 2015. Thai authorities unveiled the restored centerpiece Friday of the Erawan Shrine, in the latest bid to restore confidence among Bangkok's tourism and business communities almost three weeks after a deadly bombing. (Photo by Sakchai Lalit/AP Photo)

Isabella Santiago of Venezuela (C) is kissed by runner-ups after she was crowned Miss International Queen 2014 at the transgender/transsexual beauty pageant in Pattaya November 7, 2014. Some 22 contestants from 18 countries, all born male, competed in the week-long event for the crown of Miss International Queen. (Photo by Athit Perawongmetha/Reuters)

German pensioner Volker Kraft decorates an apple tree with Easter eggs in the garden of his summerhouse, in the eastern German town of Saalfeld, March 19, 2014. Each year since 1965 Volker and his wife Christa spend up to two weeks decorating the tree with their collection of 10,000 colourful hand-painted Easter eggs in time for Easter celebrations. (Photo by Fabrizio Bensch/Reuters)