EgyptAir Inquiry Focuses on Human Element

Suspicion mounted Friday that the crash of EgyptAir Flight 990 was caused by a human hand and not mechanical failure as federal investigators released evidence that experts said may indicate a struggle for control in the cockpit.

While steadfastly avoiding speculation, National Transportation Safety Board Chairman Jim Hall told reporters that the Boeing 767’s flight data recorder showed that the jet’s two engines were shut down as it dived toward the ocean and that the positions of its “elevators”--important control surfaces in the plane’s tail that regulate climbing and descent--were split, with one up and one down.

“This does not look like any kind of structural or system failure,” Barry Schiff, a former TWA captain and air crash consultant, said after reviewing Hall’s new information. “There was something funny going on in that cockpit.”

Separately, a knowledgeable engineer said that a split in the elevators can occur on a 767 if one of two control yokes in the cockpit is being pushed forward forcefully, while the other is being pulled back equally hard. The elevators, part of a wing-like structure in the tail, normally would operate in tandem.

“It looks as though there were contrary maneuvers--one person does one thing and another person does another,” Schiff said.

As for shutting off the engines, “once you do that, you commit yourself to an oceanic ending,” Schiff added.

Hall also revealed that the plane’s passengers were in a state of weightlessness for about 20 seconds during the terrifying dive.

In New York, FBI spokesman Joe Valiquette said that law enforcement officials have not found evidence that a criminal act was to blame for the Oct. 31 crash, which killed all 217 people aboard.

“We haven’t discovered anything that so far would indicate that a crime or terrorist act was committed,” Valiquette said. While such events are extremely rare, jetliners have been crashed by intruders who invaded cockpits and by suicidal flight crew members.

Briefing the media at a command post in Newport, R.I., Hall said that he hopes recovery of the jet’s cockpit voice recorder would explain what transpired. That recorder--the second of the plane’s two black boxes--is the object of an intense, round-the-clock search in the waters off Nantucket Island.

The search was interrupted by heavy seas Thursday but, with favorable weather forecast for the weekend, Navy ships were set to resume their work.

“We cannot at this time explain the circumstances that were occurring on Flight 990 that resulted in [this] flight profile,” Hall said. “We will not attempt to speculate about it.”

The NTSB is considering every possible explanation, including equipment malfunction, a human blunder or a combination of the two. The FBI is looking into the backgrounds of the plane’s passengers, cargo and crew for any indication of a criminal act, such as a takeover of the flight deck or detonation of a small bomb. The NTSB is leading the investigation, with the FBI in a supporting role.

The new details released by Hall help fill in a larger picture sketched earlier with the aid of preliminary flight recorder data and radar tapes.

Flight 990 was cruising uneventfully at 33,300 feet when someone or something disconnected the autopilot. About eight seconds later, the plane was put into a steep dive, and power to the engines was reduced.

For the next 20 seconds, the 767 swooped down in an arcing dive that produced a state of weightlessness for the people inside. Aircraft flying in the earth’s atmosphere can create temporary weightlessness by flying in an arc that creates centrifugal force equal to the force of gravity. The maneuver is routinely used to train astronauts but is not something commercial airline passengers would ever expect to experience.

During this period of weightlessness, pillows and blankets could have been floating through the cabin, not to mention passengers who had unbuckled their seat belts.

As the jet approached the speed of sound, an automatic “master” alarm would have sounded in the cockpit, Hall said. Flight 990 was hurtling nose-down at an angle of 40 degrees.

Then the plane started to level off. Instead of weightlessness, the people inside would have experienced gravitational forces that pressed them into their seats, as if they had hit the bottom of a roller coaster. They would have felt as if they were 2 1/2 times their normal weight, Hall said.

At this point in the dive, the elevators in the jet’s tail split.

“You don’t make extreme contrary maneuvers like that unless there are contrary motives,” said Schiff, the veteran pilot. “Someone had a change of mind or there were contrary motives--one person does one thing and another does another.”

A few seconds later, Hall said, the engine controls were changed from “run” to “cut-off.” The 767’s engines shut down.

“There’s no reason to shut the engines down, no reason at all,” Schiff said.

The flight data recorder, which captures at least 55 different types of information, stopped working somewhere below 18,000 feet. Separately, radar tracking data show that Flight 990 descended to about 16,000 feet and then climbed back to 24,000 feet before its final plunge into the ocean.

A Boeing spokeswoman said it is possible that the plane could have climbed again without the aid of its engines, because it was going fast enough to create lift. But it is not known whether that is what happened.

Air disasters are usually caused by a combination of human error, weather and mechanical malfunction.

Pilot suicide has been blamed for at least three commercial aviation crashes in the 1990s. Only last month, an angry Air Botswana pilot crashed his French-built ATR turboprop 42-seater into the airline’s two other large planes on a runway. The pilot was alone and no one on the ground was killed.

Suicide is suspected in a 1997 crash that killed 104 people on a jet flying from Jakarta, Indonesia, to Singapore.

And in 1994, a Royal Air Maroc pilot despondent over a love affair gone sour crashed another ATR into the ground, killing 44 people.

Alonso-Zaldivar reported from Washington and Malnic from Los Angeles. Times librarian Jacquelyn Cenacveira also contributed to this story.