In this undated black-and-white file photo provided by then-UN Secretary General Dag Hammarskjold, Richard J. Fecteau of Lynn, Mass., is weighed and measured by a Chinese nurse, according to information received by his mother Jan. 21, 1955, with this snapshot.

Washington ? Detail by painful detail, the CIA is coming to grips with one of the most devastating episodes in its history, a botched cloak-and-dagger flight into China that stole two decades of freedom from a pair of fresh-faced American operatives and cost the lives of their two pilots.

In opening up about the 1952 debacle, the CIA is finding ways to use it as a teaching tool. Mistakes of the past can serve as cautionary tales for today’s spies and paramilitary officers taking on al-Qaida and other terrorist targets.

At the center of the story are two eager CIA paramilitary officers on their first overseas assignment, John T. Downey of New Britain, Conn., and Richard G. Fecteau, of Lynn, Mass., whose plane was shot from the night sky in a Chinese ambush.

The mission was quickly smothered in U.S. government denials, sealed in official secrecy and consigned to the darkest corner of the spy agency’s vault of unpleasant affairs.

Downey was the youngest of the four. At 22, with one year of CIA service, he was destined to spend the next 20 years, three months and 14 days in Chinese prisons. His CIA partner, Fecteau, was 25. He was behind bars for 19 years and 14 days.

Both survived. Their pilots, Robert C. Snoddy, 31, a native of Roseburg, Ore., and 29-year-old Norman A. Schwartz of Louisville, Ky., did not.

Bits and pieces of the story surfaced over the years. But the lid was largely intact until a series of disclosures — some required of the CIA, some not — revealed a tale of tragedy, miscalculation, misery and personal triumph, as well as the agency’s misplaced confidence it could manipulate events in China.

Three years ago, the CIA declassified an internal history of the affair. Now it’s hired a filmmaker to produce an hourlong documentary. The CIA does not plan to release the film publicly. But the agency premiered it for employees on Tuesday at its Langley, Va., headquarters, and an AP reporter attended.

Downey and Fecteau declined through CIA officials to be interviewed for this story. They attended the film screening and were flooded with applause and agency autograph seekers.

‘Smacked of amateurism’

Their tale forms part of the backdrop to today’s uneasy U.S.-China relationship, especially Beijing’s anger over American military support for China’s anti-communist rivals on Taiwan.

In the early years of the Cold War, the CIA had a rudimentary paramilitary force — those with specialized skills to conduct high-risk, behind-the-lines operations.

Downey and Fecteau were assigned to a covert program called “Third Force,” intended to create a resistance network. Small teams of noncommunist Chinese exiles were airdropped into the Manchuria area of China to link up with disaffected communist generals.

The goal was to destabilize Mao Zedong’s new government and distract it from the Korean War, which Chinese forces had entered two years earlier.

The plan failed — badly.

“The CIA had been ‘had,'” the late James Lilley, who helped train agent teams for insertion into China, wrote in his 2004 memoir, “China Hands.” There were no dissident communist Chinese generals to be found, and the Chinese on Taiwan and Hong Kong who sold the idea turned out to be swindlers, Lilley wrote.

“The whole program smacked of amateurism,” CIA historian Nicholas Dujmovic says.

Donald Gregg, who came into the CIA with Downey in 1951 and had dinner with him the night before his ill-fated flight, faults those in the CIA who oversold the program.

“That was a wild and woolly, swashbuckling time in the agency’s history,” Gregg said in an interview. “There was pressure from presidents for regime change here and there, and it was a very damaging time.”

Lessons learned

On Nov. 29, 1952, above the foothills of the Changbai mountains, Downey and Fecteau flew into Chinese air space in an unarmed C-47 Skytrain. They planned to swoop low over a rendezvous point marked with three small bonfires and use a tail hook to pick up a Chinese agent off the ground without landing. Downey was to reel in the agent with a winch aboard the plane.

As they descended, the sky suddenly exploded in bursts of gunfire. It was a Chinese ambush. The agent had betrayed the Americans, luring them by promising to provide important documents from a dissident leader.

After the C-47 slammed through a grove of trees, the cockpit burst into flames and skidded to a halt near the village of Sandao.

Downey and Fecteau, stunned and bruised but alive, were captured on the spot. They were hauled off to prison — first in the city of Mukden, then in Beijing — interrogated and isolated in separate cells. Each spent long stretches in solitary confinement, alone with their fears.

It was an intelligence bonanza for the Chinese. Both Americans, after a psychological battering, spilled the beans, to varying degrees.

Here lay one of the lessons: Agency officers with close links to a covert action program should not fly on such missions.

Another blunder: At a CIA base on the Pacific island of Saipan, the Chinese agent teams lived and trained together, inevitably learning of each other’s missions. So the capture of one team risked compromising the rest.

Also, Downey was well known to the Chinese operatives because he trained them. When Downey was captured, a Chinese security officer pointed at him and said in English, “You are Jack. Your future is very dark.”

Fecteau was released by China in December 1971 and Downey in March 1973, shortly after President Richard Nixon publicly acknowledged Downey’s CIA connection.

Remarkably, once home they resumed normal lives. Downey earned a law degree from Harvard and became a judge. Fecteau returned to his alma mater, Boston University, as assistant athletic director.