SEARCH FOR CLUES BEGINS; CREW DETECTS SIGNAL FROM JET'S BLACK BOX.

Byline: Robert D. McFadden The New York Times

The Coast Guard abandoned the search for survivors of EgyptAir Flight 990 in waters off Nantucket Island, Mass., on Monday, but recovered a large piece of the plane and detected submerged pinging signals, apparently from one of the black boxes, whose retrieval could explain the jetliner's mysterious plunge into the sea.

On the second day of what was expected to be a sprawling, complex inquiry lasting months or years, investigators analyzed radar tracks of the doomed plane, questioned potential witnesses, attended to organizational tasks, set up headquarters in Rhode Island and even pursued a lead in a Los Angeles hotel where the crew had stayed.

The large questions - whether acts of sabotage, mechanical failure or human error lay behind the disaster - remained unanswered. But the recovery of some wreckage and the chance that the flight-data and cockpit voice recorders might soon be found appeared to represent significant early progress.

Like many aspects of the early investigation, numerous facts begged for interpretation and elaboration - the meaning of the radar tracks, for example, and the size and significance of the wreckage found - but no immediate conclusions were forthcoming from officials.

``We are dedicated to finding the cause of this tragedy,'' James Hall, the chairman of the National Transportation Safety Board, said at a news briefing in Newport, R.I. ``Factual information may not be developed as quickly as the press may like,'' he said, but he added that the American and Egyptian people would be kept abreast of all the relevant facts.

In an inquiry that will undoubtedly produce many leads, an intriguing one surfaced Monday. A law-enforcement official said the FBI was checking a report that an EgyptAir 990 crew member had complained to the management of a hotel where the crew stayed that a briefcase had been tampered with.

Agents took a bomb-sniffing dog to the room where the crew member stayed, and it reacted to a bag of sugar near a coffee maker. The sugar and some loose wires found in the room were sent to FBI labs in Washington for analysis. At the moment, investigators do not believe that there was ever a bomb or bomb materials in the room. They said they were not attaching much significance to the lead.

U.S. intelligence officials reiterated on Monday that they had no evidence of terrorism in the EgyptAir case. A review of the plane's cargo manifest suggested nothing out of the ordinary: it listed computer and dental equipment, aircraft spare parts for EgyptAir, and luggage.

The FBI, which was taking a clearly subordinate role to the safety board, assigned more than 600 agents to the inquiry, many from its New York, Los Angeles and Newark, N.J., field offices. Hundreds of additional state and local law-enforcement officials were involved, as well as others from the Defense Department, the Federal Aviation Administration and other agencies.

While a review of recent intelligence data collected by national security agencies and eavesdropping techniques had unearthed nothing yet to suggest any criminal threat against the plane, one senior official noted that more than 30 Egyptian military officers had been on the flight, along with some diplomats, and that their presence might have increased the risk of terrorism.

The sheer number of investigators involved was suggestive. ``We wouldn't be doing this if it was abundantly clear that it was an accident,'' the senior official said. But he added, ``We don't really know.''

Many of the investigators had already interviewed baggage handlers, caterers, mechanics, ground crews, drivers of fuel trucks, customer-service workers and others who had come in contact with the plane and its occupants in recent days. ``Everyone seems to have checked out and everyone cooperated,'' said Robert Kelly, director of aviation for the Port Authority of New York.

Much of Monday was devoted to getting organized, an effort that centered on Quonset Point, R.I. A morgue was set up for the remains of the victims, and a hangar was selected to house the wreckage of the plane, which may be pieced together in months ahead. And accommodation was being arranged in a motel for families of the victims, some of whom were flown in from New York on Monday. Other relatives of victims were expected to arrive from Cairo, Egypt, in flights on Tuesday and Thursday, officials said.

As the investigation developed, the Coast Guard shifted the focus of its search from finding victims to recovering their remains, along with their effects and the remnants of their shattered aircraft. It was a day of wrenching emotions for the families of the 217 people who went down with the plane early Sunday, for it meant the abandonment of hope that they could still be alive.

With life expectancy in the chilly 58-degree Atlantic limited to five or six hours, officials directing search operations acknowledged Monday afternoon what had been fairly obvious for a day - that there was no longer any hope for the victims, 199 passengers and 18 employees of EgyptAir.

``We believe at this point it is in everyone's interests to no longer expect that we will find survivors in this case,'' Rear Adm. Richard Larrabee said at a news conference in Newport 35 hours after the aircraft went down. ``Our thoughts and prayers are with these victims and their families. It is now a search-and-recovery operation.''

Larrabee noted that only one body had been recovered on Sunday and that by Monday only the partial remains of other victims had been found.

CAPTION(S):

3 photos

Photo: (1 -- color) Debris from EgyptAir Flight 990 lies aboard a Merchant Marine training ship Monday.

Kevin Cronau/The New York Times

(2 -- color) A crewman recovers debris from EgyptAir Flight 990 south of Nantucket Island. A large piece of the plane was also recovered.

Daniel Robson/The New York Times

(3) Tarek Anwar, brother of Adel Anwar, co-pilot of Flight 990, awaits news of his brother's fate in Cairo.

Susan Watts/New York Daily News