Posted on 06/25/2002 9:41:13 AM PDT by Asmodeus
TAIPEI, Taiwan - The initial probe of a China Airlines crash is ruling out an explosion and pilot error as causing the Boeing 747-200 to break up over the Taiwan Strait shortly after takeoff last month, the chief investigator said Tuesday.
Investigators are considering the possibility that metal fatigue, structural failure or engine problems brought down the Taipei-Hong Kong flight, killing 225 passengers and crew, said Kay Yong, the chief investigator at Taiwan's Aviation Safety Council.
Flight CI611 suddenly split into four pieces about 20 minutes after takeoff on May 25. The pilots indicated no problems before the plane disappeared from radar screens and crashed near the Penghu island chain, off Taiwan's west coast.
Yong said the disaster apparently wasn't caused by a fuel tank explosion, bomb, missile or meteor.
"From the bodies and wreckage that have been recovered so far, we haven't seen any signs of burning or an explosion," Yong told reporters.
After analyzing the plane's so-called black boxes, or cockpit voice and flight data recorders, Yong said that the devices showed no evidence of flight operation errors, such as pilot mistakes or communication problems. "Seventy percent of air accidents are caused by flight operation," he added.
The chief investigator said the flight data recorder indicated that one engine seemed to be running slightly abnormally. But it was unknown if this was related to the crash, he said.
In the flight's final seconds, the plane climbed at three times its previous rate — from 3,960 meters (1,200 feet) per minute to 11,220 meters (3,400 feet) per minute, he said.
"The ascent should have been more gradual," Yong said, but he added that such a steep ascent shouldn't have caused problems for the plane.
The investigator also said that a security review of the passengers showed no evidence that any of them were carrying hazardous materials. There was also no evidence that any passenger purchased large amounts of insurance as part of a suicide plan that would enrich relatives, he said.
Earlier this week, Yong said the plane's cockpit voice recorder picked up several unusual sounds, but investigators have yet to identify them.
Minutes before the crash, the cockpit voice recorder detected noises, some resembling a human heartbeat. The last recorded noise was a thud, Yong said. Several Boeing 747 pilots who listened to the tape said these were not sounds usually heard in the cockpit, Yong said.
"The CVR recorded a noise that sounded like "ka ta, ka ta, ka ta," Yong said. The last noise was a sharp "thud" before the power went off, he said."
Taiwan coast guard inspect the China Airlines flight 611 cockpit recovered from the Taiwan Strait, Sunday, June 23, 2002, on the outlying Taiwan island of Penghu.
If this is true, I think it is a first for a 747.
Engine problems are highly unlikely, since a 747 can stay in the air with only one engine. However, pilot error after an engine failure may be a possibility, esp. if two engines went out on the same wing. (I don't know how well Chinese pilots are trained, but if its anything like their military pilots, I wouldn't rule out pilot error just yet.)
What happened to "their military pilots"?
An engine failure won't disintegrate an aircraft, will it?
Comically wrong numbers here. 3,960 meters=12,992+ feet; 11,220 meters=36,811+ feet.
The figures in feet look like possible rates of climb for a 747; in meters, definitely not.
Correction: The article's figures in feet.
If this is true, I think it is a first for a 747.Make that at least a third or a fourth (or a fifth?) for aircraft of the 747's vintage - these craft now have a LOT of history and a variety of failures in the air as part of their history ...
It still doesn't make any sense at all.
Let's do a littel math to see what he implied by saying,
"In the flight's final seconds, the plane climbed at three times its previous rate — from 3,960 meters (1,200 feet) per minute to 11,220 meters (3,400 feet) per minute."
3960 feet per minute = 66 feet per second
11200 feet per minute = 187 feet per second
The cruise speed for 747 is 850 feet per second (Mach 0.85)
So roughly the increase in the velocity vevtor was 187 ft/s minus 66 ft/s = 119 ft/s.
In how long time? The article said "In the flight's final seconds". Let's assume it amde it in 3 seconds.
Therefore the acceleration rate is 119 divided by 3 = 40 ft /s2, about as much as 1.25 "G" (32.15 ft/s2).
It's not a big deal for 747 and I believe it has no problem to sustain 1.25 "G".
Human error and external forces did not play a role in the crash of China Airlines flight CI611, said officials from the Aviation Safety Council yesterday. "The most important finding from the `black boxes' is that we can rule out flight operation error as the cause of the accident," said ASC Director Yong Kay. "Now that we've ruled this factor out, it will be easier for us to find the focus for further investigation," Yong said, explaining that 70 percent of the aviation accidents were results of operation error.
Yong also said that investigators have also not found any evidence indicating that external forces played a role in the crash, since the wreckage recovered so far shows no signs of fire or an explosion.
On May 25, the Hong Kong-bound Boeing 747-200 passenger jet broke up in midair and crashed into the Taiwan Strait, killing all 225 passengers and crew on board. The two so-called "black boxes" -- the cockpit voice recorder and the flight data recorder -- of the airliner were retrieved last week from waters near Penghu. The ASC released its preliminary findings from the flight data recorder yesterday. The findings from the cockpit voice recorder were released on Sunday.
Yong said that before the flight data recorder lost power at 3:27:58pm, its data revealed "slight abnormal changes" in its vertical acceleration, ascending rate and engine pressure ratio before the plane crashed into sea. Yong said that recorder's data revealed that the vertical acceleration experienced a 0.25G (gravity) change, and the plane had a abnormal increase in its ascending rate, going up from 3,960m to 11,220m per minute. He said that the engine pressure ratio of the aircraft's engine number four reduced from 1.52 to 1.49.
Yong, however, stressed that these variations were acceptable within cockpit operations and the data gathered from the two recorders showed that the pilots did not react to such changes. "These changes [in the plane's system] are within the airliner's tolerance. If it had landed in Hong Kong, these changes would be totally acceptable," he said.
Moreover, cross examination of the data showed that the flight data recorder did not indicate any unusual system changes at the times when cockpit voice recorder picked up strange noises.
Minutes before the crash, the cockpit voice recorder picked up three different series of unusual sounds which have bewildered the investigators.
Since there was no major abnormal data shown in the flight data recorder, Yong told reporters that the most important thing would be to run the cockpit voice recorder through sound spectrum analysis. "It [sound spectrum analysis] might give us a clearer direction in our further investigation," he said.
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