Old-timers with long memories knew it was there. Archivists gave it a special place in the history books. But millions of people passed by the wreckage without a clue it was there.

Then, in the summer of 1988, a woodcutter dropped a cigarette and started a 450,000-acre forest fire that laid bare the bones of a World War II-vintage B-17 bomber, 45 years after it went down on a frigid spring night carrying 10 young airmen to their deaths.Besides blackening hundreds of thousands of acres in America's first national park and triggering an uproar over firefighting policy on public lands, the intense blazes in Yellowstone also revealed some of its old secrets.

"The fires exposed a lot of old road cuts, torn up culverts and bridges, and abandoned dump sites," said Tim Hudson, Yellowstone's maintenance chief and a sanitary engineer. "We vaguely knew about all that stuff, but over the years trees had grown up around it and it became hard to get to, too expensive to remove, or people forgot about it.

"Our rehabilitation efforts following the fires have also given us an opportunity to do some monumental cleanup of old junk because we have the helicopters here to help us do it."

Besides rebuilding burned-out bridges, repairing bulldozed and hand-cut firelines and fixing trails and public facilities, park crews also raced the winter to remove all debris from the crash of the B-17, tail No. 42-30260.

Ground teams carefully collected the shattered, rusted pieces of .50-caliber machine guns, splinters of practice bombs once filled with sand and dozens of bullets.

Much of the aluminum and steel already twisted by the crash was charred from the North Fork fire. The weathered metal was loaded into helicopter slings and hauled four miles north to a sorting area inside the park near West Yellowstone, Mont.

The main wreckage and the 20-foot crater created by the massive bomber when it plowed into the ground around midnight May 23, 1943, had been covered over by initial rescue crews, so Hudson's cleanup team left it undisturbed.

"The stuff we pulled out totals about 25,000 pounds," said Hudson. "We flew all the bullets out first, then dumped and burned their powder. The biggest piece we recovered was a wing tip. We also found the vertical and horizontal stabilizer on the tail section a mile from the main crash site."

Even the archivists had missed that one on their maps and charts because, in the past half century, the forests of Yellowstone had grown up around the site to create a living green shroud.

Hardly any wreckage was recognizable. Park records indicate that a few years after the crash a Yellowstone ranger salvaged enough aluminum to make a snow plane, forerunner of the snowmobile. The area also showed signs of earlier scavenging and looting. Nothing recovered this fall was deemed usable, so the park service, with Department of Defense approval, will sell it as scrap to the highest bidder.

Poking through the forest fire's ashes, park employees also found small reminders of the airmen who died.

"We found part of a leather jacket, a shoe, some pieces of belts and rings off of parachute harnesses," said Dick Bahr, Yellowstone's air operations supervisor. "There was no identifying markings on any of the personal gear so we sent it to a mortuary to be incinerated."

It was precious little to commemorate the burial ground of an airplane once hailed as "The Queen of the Skies" and singled out by the Smithsonian Air and Space Museum as the most powerful weapon in the war against Hitler's Germany.

In 1983, park service historical archivist Andy Beck collected every scrap of information he could find about aircraft No. 42-30260 and compiled it in a plastic ringbinder now kept at Yellowstone headquarters.

The plane, with 11 men on board, was flying from Marysville, Calif., to its home base at Lewiston, Mont. According to an Army Air Corps investigation, the pilot climbed to 15,000 feet above Reno, Nev., and soon hit rough air. He was flying by instruments.

Next to the line citing "Nature of Accident" was this notation: "Airplane encountered icing conditions. No definite knowledge of what happened."

Retired Yellowstone Park Ranger Tom Ela never knew the cause but he remembers the crash well.

"My wife, Betty, and I'd been to a birthday party and had just gotten home when we heard the plane go over. I went to the window because I knew it wasn't sounding right. We could hear it go into a scream as it went down."

Ela rushed to a nearby observation plateau and saw the sky alight with flame. The plane, carrying live ammunition, burned on impact.

There was confusion about the number of men aboard, so Ela was among searchers looking for survivors. On the third day, when he clibed a tree and hollered "Hallooooo" for the hundredth time, an answering call came back.

"He said his name was McDonald, he was very, very cold, and he asked `Where am I?' because he had no idea," recalled Ela, who now lives in Santa Fe, N.M.

"When I told him he was in Yellowstone National Park he couldn't believe it. He told me he'd been sleeping right by the hatch with his parachute on. Apparently he'd had a tight squeak before on a flight and he was the only one in the crew who had his 'chute on.

"When he heard in his headphones `THIS IS IT! THIS IS IT! GET OUT!' he just rolled out the hatch and pulled the cord. He saw the plane crash below him and knew he'd made it but didn't know if anybody else did. That was bothering him a lot."

McDonald told Ela that later, as he'd wandered alone in the woods for two days, he'd wondered if he'd had a nightmare and bailed out by mistake as his plane flew on to its home base.

The Army listed Lt. William McDonald, bombardier, as the only survivor. After leading McDonald out of the woods, Ela helped pack out on horseback the dead men and the plane's top-secret equipment.

The official investigation concludes that 2,000 square feet of Yellowstone were damaged, the aircraft was totally destroyed, and the pilot absolved the park service of any blame.

Hudson, Bahr, and other park employees agreed that working on the B-17 cleanup had been an interesting chapter in the story of the Yellowstone fires. Next summer they hope to tackle an even bigger rehabilitation project.

"There's a B-47 bomber still out there in an area that didn't burn," said Hudson. "It crashed in 1963, killing four Air Force crewmen, without any fire or explosion. We estimate its wreckage at 85,000 pounds. If we can get the big helicopters back in here next summer that ought to keep us busy."