YUMA, Ariz. - In the entire U.S. arsenal, only the Marine Corps' Harrier attack jet can lift straight up off a runway, hover like a hummingbird, then blast off toward its target. Though many had died flying it, Lt. Col. Peter E. Yount never thought the plane would let him down.
"Difficult but honest," he called it.
But in 1998, the Harrier betrayed him - not once, but twice. High above the Southern California desert, the plane's engine quit and refused to restart. Then, when Yount ejected, his seat rotated out of position and his parachute harness smacked violently against his helmet.
The 42-year-old father of two young girls died instantly of a broken neck.
The accident was familiar: Despite three decades of effort and billions of dollars spent to improve it, the Harrier remains the most dangerous airplane flying in the U.S. military today.
It has amassed the highest rate of major accidents of any Air Force, Navy, Army or Marine plane now in service. Forty-five Marines have died in 143 noncombat accidents since 1971. More than one-third of all Harriers ever in service have been lost to accidents.
Yet the Marine Corps is not only pressing ahead with the Harrier but also with a second trouble-prone aircraft that takes off vertically, the V-22 Osprey troop transport.
After 20 years in development and the expenditure of $12.6 billion, the Osprey is still undergoing testing to prove its safety. Twenty-three Marines died in two crashes in 2000 alone.
Undeterred, the Marines are to receive a version of the next-generation Joint Strike Fighter that can take off after a short roll and land vertically. The Joint Strike Fighter is being developed for the Air Force and Navy as well, but only the Marine model will have this capability. Still more such planes are envisioned.
This devotion to the Harrier, and to the challenging concept underlying it, is all the more striking because of the plane's peripheral combat role.
"If the Harrier had been decisive many times in battle, we would all still regret horribly the tragedies of the pilots who have been killed, but at least you'd be able to say that the Harrier made a difference," said Philip E. Coyle, the Pentagon's chief weapons tester in 1994-2001.
"What makes this situation so difficult is that we just don't have that kind of battlefield record to support the accidental deaths."
In the Persian Gulf war in 1991, for instance, the hot thrust-producing nozzles in the heart of the fuselage - which allow the Harrier to rise and balance in the air - made the plane a magnet for heat-seeking missiles. Its loss rate was more than double that of the war's other leading U.S. combat jets. Five Harriers were shot down, and two pilots died.
Critics add that, in the past decade, the use of laser-guided ordnance by high-flying conventional bombers and unmanned drones has diminished the need for the Harrier's brand of close air support.
Afghanistan provided just the kind of austere battlefield where the Marines had maintained the Harrier would make a crucial difference. Yet U.S. commanders held the Harrier out of the first four weeks of combat.
High hopes for plane
The Marines hope the Harrier will play a more significant role in a potential war with Iraq. But given the plane's limitations, many defense officials and military analysts doubt it.
In part, the Marines' persistence with the crash-prone aircraft springs from their position as the smallest of the U.S. combat services and their dependence on their financial overlord, the Navy. Since 1957, the Corps has nurtured the dream of a flying force so different from those of the other branches that its independence would be assured.
At the heart of this vision has been planes that could be positioned close to the edge of combat, able to provide transportation and cover for troops without depending on aircraft carriers or traditional airfields.
The hybrid aircraft were to combine a helicopter's ability to lift off from small clearings or damaged runways and an airplane's speed to race to the rescue of Marines in trouble.
The result, generations of senior Marine commanders have believed, would be a fighting force that was invincible and indispensable.
The Harrier, said one general, was "an answer to a prayer."
It was clear early on, however, that the answer came at a price.
The officers who died in Harrier accidents ranked among America's most accomplished aviators. They typically finished near the top of their flight school classes, often aspiring to become squadron commanders, generals or astronauts.
The Marines acknowledge they have had a rough ride with the Harrier but they say it has been worth it. Accidents, they say, are the price of technological progress, and the Harrier has proven its value in combat while paving the way for a superior successor. They deny needlessly jeopardizing lives in pursuit of their vision of a pioneering air wing.