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)

This photo taken on June 19, 2017 shows Indian yoga teacher Mahesh Yogiji attempting a world record for the longest yoga session in Ahmedabad, ahead of International Yoga Day on June 21. According to Guiness World Records, the longest yoga marathon undertaken by a man lasted 69 hours and was achieved by V Gunasekaran in Tamil Nadu in June 2016. (Photo by Sam Panthaky/AFP Photo)

American actress Dakota Johnson at the Red-Carpet World Premiere of Columbia Pictures' MADAME WEB at the Regency Village Westwood Theater on February 12, 2024 in Los Angeles, California. (Photo by Stewart Cook/Getty Images for Sony Pictures)

Karima Adebibe, the newly crowned face of Lara Croft, poses, with a Burmese python on the eve of the release of the record breaking new video game “Lara Croft Tomb Raider; Legend” at The Barbican on April 6, 2006 in London, England. (Photo by Gareth Cattermole/Getty Images)

Lana Del Rey, Taylor Swift and Jack Antonoff attend the 66th GRAMMY Awards on February 04, 2024 in Los Angeles, California. (Photo by Johnny Nunez/Getty Images for The Recording Academy)

English-Albanian singer and songwriter Dua Lipa performs onstage during the 66th GRAMMY Awards on February 04, 2024 in Los Angeles, California. (Photo by John Shearer/Getty Images for The Recording Academy)

Thai office workers walk past armed soldiers standing guard outside the Shinawatra Tower Two in Bangkok, Thailand, 20 May 2014. Thai army Chief Prayuth Chan-ocha early on 20 May 2014, declared martial law giving the military full control to prevent further protest-related violence in the country. The statement was issued about 3 am on 20 May (2000 GMT), according to local media reports. Prayuth has the authority to declare martial law without the consent of the government, which has had caretaker status since 09 December 2013. Thailand has been wracked by six months of non-stop protests seeking to topple the government. At least 25 people have died in political-related violence and more than 700 injured. (Photo by Narong Sangnak/EPA)

A flight deck crew prepares to launch a F18 Super Hornet from the deck of the USS Eisenhower off the coast of Virginia, December 10, 2015 in the Atlantic Ocean. US Defense Secretary Ash Carter visited the carrier with India's Minister of Defense Manohar Parrikar to demonstrate US Navy aircraft carrier flight operations. (Photo by Mark Wilson/Getty Images)