If history, as the scholar Lucien Febvre said, is the daughter of time, journalism is the harried hospital administrator who shows up to let the new mother know it's been 48 hours and someone else needs the room.

A few weeks ago, I published a story in this magazine about Lockheed Martin’s sponsorship (unfortunate in the eyes of some) of the White House Historical Association’s 2019 Christmas ornament: a gilded helicopter in honor of Dwight D. Eisenhower. In 1957, Ike had become the first president to ride in a helicopter — or so everyone assumed.

After the article came out, Ed Smith, a reader from Bladensburg, Md., called to say I had my facts wrong. Ed turned out to be a genial 80-year-old Navy veteran who took issue with two things I had written. First, he said I had erred in describing helicopters as a “new technology in 1957”; he explained that they had been in use for over a decade by that time. Ed was right, and we’ve posted a correction to the story.

But it was his second criticism that grabbed my attention: Harry S. Truman, he said, was the first president to ride in a helicopter — not Ike. Ed had been an aviation sonarman in Helicopter Anti-Submarine Squadron 3 (HS-3). In 1952, a squadron officer named Willis flew in a helicopter from HS-3’s base in Elizabeth City, N.C., to D.C.’s Anacostia naval base for a meeting at the Pentagon. “When he returned to his helicopter,” Ed said, “Truman was there wanting a hop,” so he could observe the helicopter’s new type of “dunking sonar.” Willis obliged, and Truman became the first president to fly in a helicopter.

I was excited. How often does one get the chance to revise history? But first, I had to verify the story, and Ed didn’t have any proof beyond his memories. He had joined HS-3 in 1954, and Willis, whose first name he couldn’t recall, became HS-3’s commanding officer in 1955. In his office, Willis apparently had a photo of Truman either getting on or off the helicopter, and handling what Ed called a “Mae West,” naval slang for a yellow life preserver (because of the way it plumps up a seaman’s chest).

So began my hunt for the photo, or any other evidence. (The White House Historical Association started a hunt of its own after I contacted the group, but a spokeswoman declined to comment for this piece.) Eisenhower was famously critical of the military-industrial complex, but the military-archival complex is a monument to American diligence. Alongside the historical association, half a dozen entities mobilized to research this alleged event. The Harry S. Truman Presidential Library and Museum found no mention of a helicopter ride or a trip to Anacostia in his daily schedule or Secret Service logs. The National Archives’ still photograph division turned up nothing.

HS-3 was later redesignated HSC-9 and moved to Norfolk. The squadron’s spokesman, Lt. j.g. David Tisler, was helpful, but HSC-9 had no record of the photo. And HS-3 command logs provided by the Naval History and Heritage Command showed no sign that a helicopter had flown to Anacostia in 1952 at all.

Ed was not deterred, however. He figures Willis took the photo home when he retired. “He treated that photograph like it was personal property,” he told me. “You’d have to find Willis to find the photograph.”

Squadron records had no first name for Willis, only initials. But I found him in the 1952 Register of the Commissioned and Warrant Officers of the United States Navy and Marine Corps (helpfully digitized): Albert Harrison Willis. An obituary notice from the Asbury Park Press revealed he’d died in 1991, survived by daughter Diane and son Wayne. “Sadly,” Wayne wrote, “I cannot confirm the flight with Harry Truman.” He knew of no picture and didn’t remember ever hearing this story. “I can’t imagine him not mentioning that he at least met [Truman].” Diane said she’d never heard of such an encounter either.

The story as Ed told it to me never came together. Maybe there’s more out there — I hope there is. But I had a deadline to make. Someone else needed the room.

Samuel Ashworth is a writer in Washington.