EgyptAir Flight 990 apparently was not brought down by either pilot suicide or an attempted hijacking, and a preliminary reading of the recovered cockpit voice recorder is inconclusive about any other cause, sources close to the investigation said yesterday.
Rather than solve the question of why the Boeing 767 suddenly dived into the Atlantic Ocean with 217 people, the first raw data from the recorder only adds to the mystery of one of the most puzzling crashes of the jet era.
The sources cautioned, however, that the National Transportation Safety Board's recorder specialists can perform near miracles in analyzing sounds from even damaged tape, and this tape appears to be good throughout. No attempt has been made yet to perform a computerized "sound spectrum analysis" of the recorder or to fully translate what was said. The answer could yet lie in some sounds that did not raise obvious concerns in the initial playback, the sources said.
The safety board issued a statement last night saying that the tape was in good condition and that it provided about 31 1/2 minutes of data. Safety board Chairman Jim Hall said in the statement that U.S. officials, including FBI representatives, and Egyptian officials had reviewed the tape, and "no conclusions could be drawn from their initial reviews."
Hall said a cockpit voice recorder group would begin a detailed analysis of the recording today. The group will be directed by the safety board and will include representatives of Egypt, the Federal Aviation Administration, Boeing and engine manufacturer Pratt & Whitney.
Sources cautioned that it was far too early to rule out almost any cause, including some form of sabotage. However, they said the initial reading of the tape does not indicate that the pilots fought with each other, that one or both of them attempted to commit suicide, or that someone entered the cockpit and caused the crash.
One source reported that the pilots appeared to be working together to solve some problem, but another source more familiar with the initial readout said it was too early to tell how well they were working together or on what they were working, only that they were not working against each other.
The pilots speak in Arabic, and it will be necessary not only to translate their words but for other pilots who know them well to listen to the recording for any telltale signs of stress or abnormal speech.
The sources provided no details of when the pilots knew they were in trouble nor what they said during the dive. However, Hall's statement said that a "key task" of the voice recorder group will be the correlation of timing between the voice and data recorder.
The recorder was located at 10:12 p.m. Saturday about 250 feet deep in the Atlantic Ocean by the submersible Deep Drone, operating off the Navy ship USS Grapple. Deep Drone, which also found Flight 990's flight data recorder, is owned and operated by Navy contractor Oceaneering Engineering of Upper Marlboro.
Both recorders were found among the shattered debris of the Boeing 767, which dived into the Atlantic from 33,000 feet on a New York-Cairo flight the morning of Oct. 31, killing all 217 aboard.
The cockpit voice recorder had become one of the most searched-for pieces of crash debris ever. Investigators said before the initial readout that if the voice recorder contained good data, they might quickly solve one of their most baffling crashes. If it did not, then they faced months and perhaps years of painstaking examination of wreckage and remains.
According to the data recorder, the plane had climbed comfortably to its cruising altitude of 33,000 feet, with no obvious anomalies in the data.
However, about 1:49 a.m. and 45 seconds, someone disengaged the autopilot.
Eight seconds later, the plane began to pitch forward, eventually reaching a 40-degree nose-down pitch and diving so abruptly that it was at zero-gravity for 20 seconds. That means drink carts, unbelted passengers and anything else not tied down would have floated about the cabin.
At 1:50 a.m. and 8 seconds, the plane exceeded its maximum design speed of .86 Mach, or 86 percent the speed of sound (Mach speed depends on altitude), and a master alarm warning went off, apparently an overspeed warning. Because the plane was at zero gravity, engine oil pressure dropped at about that point.
Because the master warning did not go off earlier, it is unlikely that the autopilot disconnected automatically, the cabin depressurized or that there was a fire in the engines, the auxiliary power unit, the cargo holds or the wheel well. A master warning is supposed to sound in each of those events.
About 1:50 a.m. and 22 seconds, two of the most bizarre events of the sequence occurred.
First, the left and right elevators split, with one going up and one going down. These plates at the rear of the horizontal stabilizer normally operate in tandem, making the plane either climb or descend. They are designed to split from each other if the two pilot's control columns are pushed in opposite directions with at least 50 pounds force.
The plane was designed that way to enable the pilots to control at least one of the two elevators if control cables jammed on either pilots' control column. However, investigators initially were forced to consider the possibility that there was a fight in the cockpit and the two pilots--or other individuals--were pulling in opposite directions.
Second, the engine start levers were switched manually to "cutoff." There are only two reasons to take such an action: to shut an engine down or to begin the restart sequence after it is shut down.
Almost immediately, the plane began pulling out of its dive, placing the formerly weightless passengers under 2.5 times the force of gravity.
About five seconds later, the flight data recorder stopped working, as did the altitude-reporting transponder. Those two systems would lose power if the engines were in the process of shutting down, although backup electrical systems would keep power to controls, radios and other "flight-critical" systems.
The plane then climbed from 16,000 feet to 24,000 feet, according to radar data, then apparently stalled and fell into the ocean.
CAPTION: INSIDE THE COCKPIT (This graphic was not available)
CAPTION: An FBI agent tags the cockpit voice recorder onboard the USS Grapple before it was flown to Washington.