This story is part of a series called "Faces of the Vietnam War." KQED recently asked our audience to submit their stories about the Vietnam War. We heard from refugees, military veterans, journalists, activists and more. This story is about San Francisco resident John Dubpernell, 67, who served in the U.S. Army during the war.

Anniversaries can be important for veterans. “For me, it’s March 5,” said veteran John Dubpernell. On that date in 1971, he was a door gunner serving in Vietnam with the 282nd Assault Helicopter Company, which was providing air support for the South Vietnamese army during an operation called Lam Son 719. “Vietnam’s version of D-Day” is what he calls it.

The U.S. military deployed many helicopters during the massive campaign, including Dubpernell’s Huey. One day, while his aircraft was returning from a dangerous mission, a mayday call came over the radio. Dubpernell, who was sitting in the left doorway, looked out over the far side of the gunship and said he saw another helicopter going down in flames.

Now on high alert, his helicopter began taking fire. “I don’t know whether I hear or feel the aircraft taking hits,” he recalled. “So I immediately started firing below.” After they got clear of the area, Dubpernell said he noticed that his seat, which had been modified to include an armor plate by a previous crew member, had stopped an AK-47 bullet. “That saved my life,” he said.

Lam Son 719 was one of the bloodiest battles in the war, and Army helicopter crews suffered heavy losses.

For decades, Dubpernell avoided the anniversary of the day when he was nearly killed. “When I came home in December of 1971, I put a weld around the door that was that part of my life,” he told KQED. It was only much later, in the late '90s, that he would revisit his time in Vietnam.

Dubpernell had been drafted into the Army in June 1970 and served on UH-1 Huey gunships, which he calls “the Jeep of the sky.” He was stationed in Da Nang, a city on Vietnam's central coast, and quickly rose through the enlisted ranks to become a crew chief -- a job that made him responsible for the whole helicopter, including its maintenance, fueling and more.

To this day, Dubpernell still holds the fellowship of being on a combat flight crew in high esteem. “There's that unspoken aspect of camaraderie,” he said. “In civilian life, you'll never experience it.” But his combat experience left him traumatized and disenchanted.

The urge to put Vietnam behind him began soon after Dubpernell returned home. Revelations about the government’s dishonest handling of the war only deepened his desire to forget his experiences, he said. “I read Daniel Ellsberg's 'Pentagon Papers' and that's when it really cemented my feelings about Vietnam -- really putting a weld around the door and wanting to forget the whole thing,” he said.

When he was 41, Dubpernell got laid off from his job as a production coordinator for a San Francisco-based printer and began searching for meaning in life. He ended up reading "When Heaven and Earth Changed Places," a memoir by Vietnamese-American author Le Ly Hayslip about her experience of the war as a child. In it, he learned that Hayslip had founded a nonprofit called East Meets West, which provides support for a government-run orphanage in Da Nang.

Dubpernell decided to visit the orphanage, called Village of Hope, in December 1998. “I just had this compelling desire to go back to Vietnam. And in my heart, I wanted to correct all of the wrongs that were done,” he said.

While Dubpernell was visiting the East Meets West offices in Da Nang, the staff told him they were planning to celebrate Christmas with the kids in the orphanage and invited him along.

“We're even going to have a Santa Claus,” he remembers them saying. Back at his hotel, Dubpernell thought about the celebration and came to a decision: “I'm saying to myself: I want to be that Santa Claus. I've got the moustache.”

The staff agreed and Dubpernell, dressed as St. Nicholas, shared dinner and gifts with the children at Village of Hope. The experience was so gratifying that he went back. “I have done three trips, each time going back in December and playing Santa Claus in Da Nang,” he said.

Following that first visit, Dubpernell started experiencing severe symptoms of post-traumatic stress disorder (PTSD). In the decades following his deployment, he'd struggled with anger issues, but his return to Da Nang set off a new series of reactions.

“I was a basket case in terms of crying,” he told KQED. “I was drinking heavily.”

Some friends, fellow combat veterans, grew concerned when they recognized his symptoms and urged him to seek help.

Dubpernell followed their advice and enrolled in a mental health program at the VA’s San Francisco medical center in 1999.

Once he was diagnosed with PTSD, Dubpernell committed himself to treatment and still attends group therapy three times a week. “All those years I invested in my PTSD therapies, it pays off,” he said.

The trauma Dubpernell experienced has affected his life in other ways, too. “Like other people dealing with PTSD, relationships are a real challenge,” he said.

Dubpernell, who came out as gay shortly after he left the military, described a fraught romantic life. “I think the longest relationship I ever had was two months, so it was very difficult.”

During his deployment, he remembers he had to be on guard for fear of revealing his identity as a gay man. But in the years since, Dubpernell said that other Vietnam veterans have been accepting of his sexual orientation. “It was a non-issue, as long as you did your job,” he said. “And I did.”

Although his return trips offered Dubpernell a chance to make amends and connect with a new generation of Vietnamese children, they were bittersweet. During his visits to Da Nang, Dubpernell said, he repressed the feelings that came back to him until he got home, just like he had during the war.

“In Vietnam, you had a job to do and you couldn't allow your emotions to get in the way,” he said. “When I was doing my Santa thing I couldn't allow my emotions to get in the way, because I had a job to do: playing Santa Claus."

KQED's Peter Arcuni contributed to this story.