Two Systems Down in KAL 801 Crash
The glide slope at the airport and the plane’s
altitude warning system were out of service
By Lori Tighe
Wednesday, March 25, 1998
The flight crashed into a hillside near the Guam airport on Aug. 6, 1997, killing 228 people. The National Transportation Safety Board is holding hearings here this week to try to determine the cause of the crash.
The glide slope, which acts as a tractor beam to guide the plane down, was being typhoon-proofed to safeguard it from storms.
The minimum safe altitude warning system (MSAW), a high-tech computer system that warns air traffic controllers about planes flying too low, had been reconfigured, and in effect decommissioned, because of too many false alarms.
Kurt Mayo, Guam radar controller, said he thought the crew knew the glide slope was down. He also said he wasn’t aware the MSAW had been reconfigured and was basically useless.
“Any doubt in your mind the crew would have known the glide slope was out?” asked Richard Wentworth, an investigator with the National Transportation Safety Board.
“No,” Mayo answered.
If MSAW had worked, Guam air traffic controller Marty Theobald told the investigating board, “I would have alerted the plane to check their altitude immediately.”
After the Guam accident, officials from the Federal Aviation Administration testified they checked MSAWs in all 50 U.S. states to ensure they worked.
“Technology has worked, but one of its revenge effects is relying on it to an inappropriate degree,” said Jim Burnett, former chairman of the National Transportation Safety Board and now a transportation safety consultant.
He said he found the hearing’s first day of testimony informative.
“There were additional problems with air traffic control. Everyone was supposed to know about the two critical systems down, but not everyone knew,” Burnett said. “False signals may have indicated to the captain it was working. We’ll hear more about that later.”
The pilot of Flight 801, Capt. Yong-Chul Park, received notice before the flight of the downed glide slope, which wouldn’t guide him through the mountainous terrain near Guam’s airport.
According to the cockpit recorder, Park even briefed his crew about the downed glide slope. But in the minutes leading up to the crash, the captain and crew went back and forth about whether the glide slope was working.
The Safety Board said it became concerned about the possibility of “spurious” radio signals, possibly leading the captain to believe the glide slope worked after all. Witnesses will testify about electronic interference that may have contributed to the crew’s confusion.
The crew’s final caution, a ground proximity warning system on the plane, apparently warned the crew they flew too low, Burnett said. “But in this case they weren’t quick to respond to it.”
Another suggestion involved the possibility that Asian cultural respect for authority might have caused the crew not to challenge the pilot about the danger.
“It’s the kind of thing you have to look at,” Burnett said. Cultural differences among international flight crews have played a part in past plane crashes, he said.
“A classic story of one was a plane crash in Spain, where the air traffic controller was yelling, ‘Pull up! Pull up!’ and the captain said, ‘Shut up, gringo,’ before he flew into a mountain,” Burnett said.
But Muchol Shin, spokesman for Korean Air, smiled and shook his head at the suggestion the Korean crew failed to protest to the Korean captain before the crash.
“A cultural issue was not a case here. They were too busy with the landing procedure and thought everything was normal,” Shin said.
Koreans have two language protocols based on age, he said. Younger Koreans use “sir” with older Koreans, for example. The older engineer on Flight 801 didn’t use “sir” a few times when addressing the younger captain on the cockpit recording, Shin said.
“I would rather put it as an ill-fated flight where everything went wrong,” he said.
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