Cameras seem weightless, flying through the air in Paul Octavious’ Birds Of Aperture series.

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)

Actress Hiba Abouk attends Hugo Boss night party 2011 on December 13, 2011 in Madrid, Spain. (Photo by Carlos Alvarez/Getty Images)

Soldiers evacuate a hostage from a mass shooting scene at the Terminal 21 shopping mall in Nakhon Ratchasima, Thailand, 09 February 2020. According to media reports, at least 21 people were killed, and as many as 30 wounded after a Thai soldier, identified as 32-year-old Jakraphanth Thomma, went on a shooting rampage with a M60 machine gun in the city of Nakhon Ratchasima, also known as Korat. Thomma held an unknown number of people hostage within the Terminal 21 shopping mall for around 17 hours before being shot and killed in a police operation. (Photo by Rungroj Yongrit/EPA/EFE)

Kenny Wallace, driver of the #09 Family Farmers Toyota, spins into Justin Allgaier, driver of the #31 Brandt Chevrolet, who is lifted into the air by Reed Sorenson, driver of the #52 Means Racing Chevrolet, as Michael Annett, driver of the #43 Pilot Flying J. Ford, tries to avoid the wreckage during the NASCAR Nationwide Series DRIVE4COPD 300 at Daytona International Speedway on February 25, 2012 in Daytona Beach, Florida. (Photo by John Harrelson/Getty Images for NASCAR)

In this Tuesday, March 17, 2015 photo, a French military plane takes off from the flight deck of the French Navy aircraft carrier Charles de Gaulle in the Persian Gulf. Aircraft aboard the French carrier are flying bombing and reconnaissance missions as part of a U.S.-led coalition targeting Islamic State militants in Iraq. (Photo by Hasan Jamali/AP Photo)

Military helicopters fly in formation above a billboard with a picture of China's late Chairman Mao Zedong during a training session for the upcoming parade marking the 70th anniversary of the end of World War Two, on the outskirts of Beijing, July 2, 2015. Troops from Russia and Mongolia will march together with Chinese forces in a parade in Beijing in September to commemorate the end of World War Two, the government and state media said on Thursday, confirming the first two foreign participants. (Photo by Jason Lee/Reuters)