Life ends at the ladder when the brown water full of sullen rainbows from the diesel fuel rises over the rubber boots, the uni-suit, the Navy Mark 12 diving gear, the yellow plastic Kirby Morgan helmet.

Life, right here, is the grumble of the Navy landing craft engines, the pigeons circling under the 14th Street bridge, the empty black body bag waiting above the ladder, the photographers leaning tiny over the railing to watch the helmet sink. The other divers stalk around hefty in their red neoprene leggings. On the riverbank is the hard-scrabble chaos of any disaster area. The disaster here is the crash of Air Florida Flight 90, last Wednesday.

The helmet eases below the surface, with the water climbing up the face mask in a dirty, jagged horizon. The water blisters with bubbles, and then it's the netherworld, a sensory-deprived solitude where everything seems to be happening in the mind. There's the hollow grate of voices from the surface over the communication system, and the odd grinding whine of propellers from the boats pushing through the ice overhead. Then the soft, dead clutch of the mud at the boots -- no need for flippers, here, no flying weightless in three dimensions, the way it is on television.

"It's crawling in the mud, is what it is," says William Herren Sr., divemaster of the Montgomery County Fire and Rescue Services, and a firefighter in Sandy Spring. Herren was part of the team diving at the crash site on Thursday and Friday. "It's not pleasant. You're very disoriented. You have to do everything by feel -- like a blind man getting used to his house. The cold isn't that bad -- you wear a Poseidon uni-suit or a Henderson dry suit over thermal underwear. Your feet freeze first, then your hands, and you can't feel that much to start with -- you're wearing three-finger rubber gloves. The wreckage is the biggest danger -- you can foul and get hung up. You have to have good control of yourself, and training and experience. You only have to mess up once. Usually divers are kind of crazy."

If death had infants, they'd be the divers crawling in mud under as much as 30 feet of river to retrieve Flight 90 -- the victims, the chunks of plane sprawled across the mud, the shoes (so many of their shoes came off at impact), the clothes, the trash.

Not only infants but blind ones: "The visibility is close to zero," says Coast Guard Cmdr. Mike Taylor, who is head of the National Strike Force Diving Team, which made its first dives Thursday afternoon, a day after the crash. "Lights will only expand the visibility field about an inch."

Two Navy salvage and harbor-clearance teams are working with Coast-Guard-supervised divers from Army engineering units. There are no more amateurs piling into the water in scuba gear the way they did when the plane first went down. The air now comes from hoses to the surface, lest the ice on the river jam open the regulators on air tanks. Supervisors watch the trails of air bubbles and keep the lines taut, to avoid kinks and fouling. The riverbank is covered with Army officers, Navy officers, police officers. But no amount of brass and organization can change what's down there in the rocks and mud.

Everything goes so clumsily. It is as slow and strange as a dream of falling or being chased, when nothing works right, your arms won't grab, your legs won't run. Rubber hands touch . . . fuselage? ceiling? a seat? Something soft, maybe a cushion, and then no give where there should be some -- the arms frozen bent where they rested on seat arms, the head pitched forward and frozen there. If the seat is upside down, the arms will be over the head, set in the sort of pose a man might be in if somebody was handing a baby to him. Rubber fingers feel for the seat-belt buckle, and pry it outwards. Then the body, knees still flexed slightly, about like the knees of a golfer making a shot, has to be worked out of the seat. It's not heavy -- a body doesn't have much weight in the water, and may even be a little buoyant if there's any of what's called "tidal air" left in the lungs. But it's clumsy, it drags, it catches on torn sheet metal.

"I've got one," the diver may say. And then he crawls back toward the lift on the front of the Corps of Engineers boat, hauling the body through the mud by a limb or a rope. If he has to, he can add air to his suit for added buoyancy.

Man, woman, old, young, hair streaming against the current, eyes open or shut, there's no way of knowing in this procession under the river ice.

"It's grim at best," says Terry Robinson, a geophysicist and a former SEALAB III aquanaut who trained in the winter in the Anacostia River, and is now retired on disability from the Naval Oceanographic Office. "There's no visibility. It's the Braille method only. It's like being in a dark room with your own thoughts. You have to try and remember which way you went, but you have to remember it in three dimensions. You're trying to control your body. You say, 'Body don't hurt, while I'm doing something important.' You can get tangled in your own lifeline, you can get caught in tangles of wire and tree branches, and the reinforcing bars construction workers throw into the river when they're building bridges."

Wreckage, Robinson says, doesn't settle "in an ideal situation. You can be walking on a wall and fall through a door. It gets really confusing."

If they're blind infants, they're also death's own midwives, bringing the people on Flight 90 out of a cold, jagged womb.

Back on the surface, where the air shakes with jets climbing over the 14th Street bridge and people keep looking up at them, this being one of the reflexes of life at the crash scene, a Corps of Engineers boat lowers its front platform into the water. A member of the diving team holds the air and communication lines and walks them along the diving platforms.

The bubbles shine bigger and bigger on the water, and then it is, say, the knee and the elbow, then the bright frozen coin of face lifting into the air, borne supine, with the brown river sagging away from a sweater and slacks. It is a man in his thirties, with a look of preoccupation on his face, as if someone had asked him to multiply two big numbers in his head and he'd closed his eyes and jutted his jaw to think about it for a moment.

That's what they see up there where life begins but by now the yellow helmet is already subsiding below the water.

There is something ancient and persistent here, a ritual, going back to the mud to salvage the dead after they have failed to fly.

"It's funny," says Herren, after a day beneath the river. "My father was a volunteer firefighter in Prince George's County, and he was out on the river after they had that plane crash in '49. I think about that."