Leaks and speculation have infused the probe of EgyptAir Flight 990 with misinformation and unnecessarily clouded the investigators' preliminary feeling that "a deliberate act" caused the fatal crash, the National Transportation Safety Board's chairman said yesterday.

NTSB Chairman Jim Hall refused to specify what misinformation had been leaked to the news media. He indicated he was referring to translations of some of co-pilot Gameel Batouti's Arabic words that were picked up by the cockpit voice recorder just before the plane began its death dive into the Atlantic. Hall also said that any misinformation came from agencies other than his own.

Earlier in the week, government sources said that Batouti had uttered in Arabic the phrase "I have made my decision" before, investigators believe, he intentionally pushed the aircraft into a dive. The sources said the translation appeared on some memos describing what Batouti had said but not on others. Now, sources familiar with the probe say that wording is not an accurate description of what Batouti had said.

"We have not released specific information from the cockpit voice recorder, and any so-called verbatim information you have heard about that recorder is unauthorized, second-, third- or fourth-hand," Hall said at a briefing.

The crash investigation has created some frenzy between the United States and Egypt, an important U.S. ally in the Middle East. And it appears that to some degree diplomacy has slowed the momentum that seemed to be pushing the probe from the NTSB to the FBI.

The NTSB was on the verge this week of passing the investigation on to the FBI for a criminal inquiry. But the Egyptian government objected to such a quick determination.

Hall did not say yesterday when the case might go to the FBI. He said that, for now, the safety board, the Egyptian government and the FBI have agreed that more work needs to be done before the investigation could meet the board's threshold for turning over the case to the FBI.

Delaying the transfer could cost the two governments millions of dollars.

Earlier, safety board sources said the plane's voice and data recorders, plus radar data, would probably be sufficient to determine a cause and that only human remains would be pulled up from the ocean floor. However, it appears now that more of the plane must be recovered to determine for certain that no signs of mechanical failure exist.

Hall said a huge salvage ship, the Smit Pioneer, was steaming from Portugal and should arrive at the crash scene 60 miles off the coast of Massachusetts by Dec. 1. It is being dispatched to bring up human remains and pieces of aircraft wreckage. The crash killed 217 people.

"As we began gathering information from radar data, the flight recorders and the little wreckage that had been retrieved, our investigators began to feel this crash might, and I emphasize might, be the result of a deliberate act," Hall said.

Under the rules of the International Civil Aviation Organization, a United Nations branch that includes almost all countries with commercial aviation, the NTSB must then inform the FBI. He said he met Monday with FBI Director Louis J. Freeh to officially inform him.

However, he said that for the FBI to become the prime investigative agency the accident must involve "obvious cases of sabotage, murder or other crimes."

"After consultations among the Egyptian authorities, the safety board and the FBI, we agreed more work needs to be done before we could reach the threshold of asking the FBI to take the leadership in this investigation," he said.

Nonetheless, after Hall's briefing, the NTSB released a timeline for the jet's dive that emphasizes the strong case, though circumstantial, that someone--believed to be co-pilot Batouti--deliberately dived the plane, regardless of what words were spoken in the cockpit.

The timeline reveals that the dive from 33,000 feet to 16,000 feet and back up to 24,000 happened in 90 seconds. The timeline does not indicate how long it then took the plane to fall into the ocean.

The sequence started when the autopilot was disconnected at 1:49 a.m. and 46 seconds. Investigators have said no alarm sounded to indicate that the disconnect was caused by a defect or some airplane stress such as turbulence. After eight seconds of smooth flight, the engine throttles were pulled back and the devices on the tail that control the plane's altitude--called elevators--began to abruptly push the plane down.

The plane reached zero-gravity status within one second. Thirteen seconds later, the plane reached its maximum allowed speed, 86 percent of the speed of sound, and a master warning sounded.

At some point during this time, the captain apparently reentered the cockpit.

Thirteen seconds later, at 21,700 feet, the elevators--which work in tandem to control up-and-down motions--split, with the captain's pointing up as if he was trying to pull out of the dive and the copilot's pointing down, which would make the plane dive.

One second later, someone cut off the plane's engines.

Four seconds later, for unexplained reasons, someone pulled the aircraft's speed brakes, flat panels on top of the wings that allow rapid descents.

The tape ended 11 seconds later at 16,400 feet, 51 seconds after the dive began. For some reason, the elevator split began to lessen in the last two seconds.

Based on radar data, the plane took about 30 seconds to climb back to 24,000 feet before falling again toward the dark waters.

Staff writer David A. Vise contributed to this report.