By GLEN JOHNSON Associated Press Writer
WASHINGTON (AP) - Despite a diplomatic dispute over what was said on the EgyptAir Flight 990 cockpit voice tape, investigators can still point to hard evidence from the plane's other ``black box'' that a human hand caused the Oct. 31 crash.
It is that evidence, documented by the plane's flight data recorder, that allowed National Transportation Safety Board Chairman James Hall to make the unusually early pronouncement that the plane did not appear to have been brought down by a mechanical problem or bad weather.
The recorder, among the most advanced ever handled by the safety board, also does not support any theory of a bomb. Some Egyptian authorities suspect a bomb brought down the New York-to-Cairo flight, killing all 217 aboard.
U.S. investigators believe the crash may have been caused by Gameel El-Batouty, a backup pilot who apparently was alone in the cockpit shortly before the crash.
The cockpit recorder picked up the sound of the right-seat occupant uttering a statement before the plane began its dive toward the Atlantic Ocean.
What was said, its translation from Arabic to English and its meaning in the Egyptian culture have triggered argument and diplomatic tension between the two countries.
``We don't even have to discuss what was said by the occupant of the right seat in order to have a prima facie case that a human being caused this accident,'' said John Nance, an airline captain, lawyer and aviation author.
Data released to date by the safety board supports no scenario for the Boeing 767's flight path other than one in which ``the occupant of the right seat disconnected the autopilot and aggressively pushed forward on the yoke, holding that big jet in an incredible screaming dive,'' Nance said.
Such analysis is based on information from the Allied Signal Universal Flight Data Recorder aboard the EgyptAir plane.
When TWA Flight 800 exploded in the skies off Long Island in July 1996, investigators were left with a flight data recorder that documented only 19 flight parameters.
The unit aboard the EgyptAir plane logged the performance of 55 aircraft systems and over 150 pieces of flight information on a computer chip.
Hall said Monday: ``The board has not found any information to believe that this is a mechanical or weather-related event that occurred. But our investigation is far from complete.''
Among the evidence gleaned from the EgyptAir data recorder:
-The plane was in a level cruise both before and for eight seconds after the autopilot was switched off, indicating it was a normal flight until the nose was pushed downward.
-The plane's master warning alarm was not sounded until 14 seconds after the dive began, the same time the plane exceeded its maximum design speed of Mach 0.86.
The alarm is designed to sound for five reasons, including excessive speed and a cabin depressurization that would likely follow the explosion of a bomb. While pilots are taught to dive to a lower altitude in the event of a decompression, the data recorder shows no loss of cabin pressure.
-The plane's elevator panels, which sit on both sides of the tail and pitch the nose up and down, made an extremely rare in-flight split in direction.
Boeing designs the 767 so the panels go in opposite directions only with a sustained push of over 50 pounds of pressure on either the captain's or the co-pilot's control stick.
In the case of Flight 990, the side linked to the co-pilot's control stick remained pushed down - pointing the nose toward the ocean - while the side linked to the captain's stick was pulled up.
Investigators believe the captain may have returned to the cockpit as the dive began and fought with the co-pilot for control of the airplane.
-Twenty-eight seconds after the dive began, the plane's engine control switches were moved from ``Run'' to ``Cutoff.'' Boeing designs the switches as ``lever locks,'' meaning they can be moved only if they are pulled outward at the same time they are lifted up or down. That prevents an accidental bump from shutting off fuel flow to the engines.
While some Egyptian officials have said the pilots may have shut down the engines to restart them, Nance said that would have been premature since the recorder shows the plane was still in a dive.
``The overwhelmingly logical conclusion is that the occupant of the right seat, whom we already know was pressing forward on the yoke, took this affirmative act of killing the engines,'' he said.