Bail out from a B-1 bomber through darkness into an unknown sea.(Knight Ridder Newspapers)

The world on the night of Dec. 12, 2001, was a dangerous place. Violence surged in the Middle East between Israelis and Palestinians. In the United States, the anthrax threat lingered as spores used in the attacks were found to match anthrax produced by U.S. Army scientists in the early 1990s. The day before, Zacarias Moussaoui, a French citizen of Moroccan descent, became the first person tied to the Sept. 11 attacks to be indicted.

In eastern Afghanistan, the siege of the Tora Bora mountain-cave complex had reached a critical stage. Al-Qaida and Taliban forces were being pounded by American B-1 bombers based 2,500 miles away on Diego Garcia, a 17-square-mile British-owned atoll of coral and sand in the middle of the Indian Ocean.

For the aviators based on Diego, this evening resembled so many others over the previous two months of Operation Enduring Freedom. The often-capricious weather was no better, but no worse, than usual, with heavy clouds and a few scattered thundershowers making for a dark night.

Shortly before 10 p.m., signals received by Diego's control tower and the destroyer USS Russell, patrolling off the coast of the island, gave fear a new shape in the war on terror.

A B-1 was going down.

About an hour earlier, Capt. William "Stainless" Steele and three crew members had taken off from Diego in a B-1 bound for the Afghan theater. The sleek, massive B-1 _ roughly two-thirds the length of a 747 jumbo jet _ can fly 4,000 miles with a full payload without refueling and is the only supersonic bomber in the U.S. inventory. One B-1 can carry more than eighty 500-pound bombs, a load that would otherwise require a squadron of fighters. It has been the workhorse of the Afghan campaign.

But a troubled workhorse: From its introduction in 1985 through 1998, six of the $280 million aircraft had crashed, making it far more accident-prone than the B-52, which it was built to replace. The pilots call the plane the Electric Jet, because it depends so heavily on complex electrical systems, resulting in a thin margin of error when those systems fail.