ELEPHANT MOUNTAIN (AP).- Flying low over snowy terrain on a Cold War training mission, Lt. Col. Dan Bulli's massive B-52 bomber hit turbulence that shook the plane so violently that he couldn't read the gauges. Pulling back on the yoke and pushing forward on the throttle, he tried to fly out of the severe wind. Then there was a loud bang.
Moving at about 325 mph, the unarmed bomber banked, nose down, toward the unforgiving winter wilderness below. Unable to control the plane, Bulli signaled for the crew to eject.
They had seconds to save themselves.
Today, the B-52 Stratofortress is a legendary aircraft, one of the longest-serving in U.S. military history, even flying missions in Afghanistan and Iraq. The planes will remain in service for years to come. But it would not have become the workhorse it is without one disastrous flight 50 years ago next week, and a similar one six days later in New Mexico, that helped to underscore a deadly structural weakness.
"When you're flying combat aircraft, you're pushing your aircraft to the edge" to simulate combat, said Jeff Underwood, historian for the National Museum of the U.S. Air Force in Ohio. "It's very dangerous and the air crew knows it."
The fateful flight originated on Jan. 24, 1963, at Westover Air Force Base in Massachusetts. The crew was learning to use terrain avoidance radar, designed to help the pilot fly at treetop level to deliver a nuclear strike. Radar advances by the Soviets forced the aircraft with a 185-foot wingspan to fly low to the ground to evade detection, causing unexpected structural fatigue, Underwood said.
The crew had a choice of two routes, one over Maine and the other over North Carolina.
Maine was selected because of better weather.
Bulli, now 90, was an experienced pilot with 9,000 flight hours, responsible for overseeing proficiency of other B-52 pilots and crews.
Others, including two instructors, joined the flight. Gerald Adler, a navigator, took the seat of the electronic warfare officer, one of only three on the plane that ejects upward during an emergency, along with the pilot and co-pilot. Remaining crew had to eject downward or bail out.
The flight started out as routine. Powered by eight jet engines and capable of carrying up to 70,000 pounds of conventional munitions, the B-52 approached rural Greenville, 150 miles from Portland. Gusts coming off the 3,000- to 4,000-foot-high mountains buffeted the plane with moderate turbulence, Bulli recalled.
Eventually, the turbulence became extreme.
"The instrument panel was vibrating so badly that I couldn't read the dials. I couldn't interpret the radar returns because it was juggling so bad. It was the worst turbulence I had ever encountered," the pilot said.
After hearing what sounded like an explosion he later learned the vertical stabilizer had broken off Bulli had just seconds to determine whether the plane was still flyable. Unable to control the aircraft, he ordered the crew to bail.
The B-52 crashed into a mountainside, killing six crew members who couldn't escape. A seventh, the co-pilot, died after slamming into a tree.
Bulli shot his ejection seat into the air, bursting through the escape hatch. He smashed his foot on the instrument panel but cleared the aircraft. His parachute snagged a tree, and he ended up dangling 30 feet above the ground.
Adler's parachute failed to deploy because he remained strapped in his ejection seat, and he tumbled through the air before crashing through trees and into the deep snow, which slowed his impact enough to save his life.
The harsh landing broke ribs and fractured Adler's skull. But worst of all, it crushed his survival kit, leaving no access to the sleeping bag to protect himself from the cold. He pulled out the unused parachute and wrapped himself in it. Bulli eventually lowered himself to the ground, dug a hole in the snow, and climbed into his sleeping bag.
The two survivors remember a strange sense of quiet, interrupted only by wind whistling over the mountainside. Neither remembers the sound of the plane hitting the mountain.
Not knowing the fate of the others, or each other, Adler and Bulli settled in for a frigid night in shoulder-high snow. As darkness descended, the temperature plummeted, eventually reaching more than 20 below.
Their fight for survival wasn't over.
For 20 hours, they waited.
The region where the plane crashed remains wilderness, part of the vast North Woods that inspired naturalist Henry David Thoreau. Rescuers had to use helicopters, snowshoes and primitive snowmobiles to reach the wreckage.
"This is still the last frontier east of the Mississippi. There are fewer people living in Piscataquis County per square mile than anywhere east of the Mississippi," said Greenville police Chief Jeff Pomerleau.
Eventually, the survivors were found. Adler had severe frostbite. He was unconscious for five days and eventually his leg was amputated because of gangrene. All told, he spent 14 months in a hospital.
Later, he left the Air Force as a captain to start a new life as lawyer and a city councilman in California.
After recovering, Bulli continued to fly B-52s. At one point, he returned to Maine to serve at Loring Air Force Base. He retired as a colonel from the Air Force in Nebraska, where he lives.
Coming at the height of the Cold War, the flight showed that risks and sacrifices even outside of combat were significant. The crash left nine children without fathers and six women without husbands, Adler said.
"People who're killed in peacetime are often forgotten. Memorial Day events often forget them. Veterans Day events often forget them," said Adler, 81, who lives outside Davis, Calif.
But the crashes in Maine and New Mexico helped to make the B-52 the reliable aircraft it is today by revealing a fatal weakness in an aircraft that wasn't designed for low-level flying: The vertical stabilizer snapped off under certain conditions.
Fifty years after the crash, much of the debris remains on Elephant Mountain. Torn pieces of riveted metal. Wing chunks with hydraulic tubes dangling. Parts of the fuselage. Bundles of wire. Wheels and strut assemblies. The 40-foot-tall vertical stabilizer remains where it landed, 1½ miles from the other wreckage.
About 10 miles away, at the clubhouse for the Moosehead Riders snowmobile club, newspaper clippings, Bulli's parachute and Adler's ejection seat are on display. The club has held ceremonies for 20 years at the site and will hold this year's on Saturday, ahead of the anniversary. Pomerleau has taken over organizing the remembrances from another club member, Pete Pratt, who helped keep memory of the flight alive for years.
Pratt has been to the crash site a hundred times, but it's still an emotional experience. Tears welled in his eyes on a recent visit.
"It's a very solemn place," said Pomerleau, who joined Pratt at the site. "You think of the families, the wives who lost their husbands, the kids who lost their fathers, the grandchildren who heard the stories. There's so much to absorb."
Copyright 2013 The Associated Press.