Friday, March 27, 1998

‘Insidious trap’
blamed in crash

Aviation experts describe a scenario
in which an off-site navigation aid
led pilots to a darkened mountain

By Lori Tighe

The crash of Korean Air Flight 801 that killed 228 people in Guam offers a textbook example of what causes most major airplane crashes outside of North America.

Aviation experts gave the final big-picture testimony at the third day of hearings yesterday, unearthing what caused the seasoned crew of Flight 801 to fly the 747 jet into a mountain Aug. 6. The National Transportation Safety Board will review the evidence and vote on the cause of the crash in about six months, officials said.

Korean Air Flight 801 flew into an "insidious trap" of what is called a controlled flight into terrain, or flying a perfectly good plane into the ground, said expert witness Don Bateman, chief engineer of flight safety systems for Allied Signal Inc. of Redmond, Wash.

This type of crash most often occurs at night in bad weather at airports near rough terrain, where the pilot has to land without critical navigation aids, said Capt. Paul Woodburn, a British Airways senior official who has led a steering committee trying to reduce the number of these accidents.

Except for North America, controlled flights into terrain cause more plane deaths worldwide than any other type of crash, Woodburn said.

Two major factors contribute to the "insidious trap": The airport's only distance-measuring equipment (DME), a prime navigational aid, stands away from the airport; and its glide slope is out of service. A glide slope serves as a traffic lane beamed from the runway to guide planes in for a precise landing.

At the time of the crash on Guam, the glide slope was down, and the only DME was on the darkened Nimitz Hill, the site of the crash.

"This is very rare," Bateman said. "I did a study of 88 airports in the Pacific Rim and found only six to have this scenario; Guam was one of them."

No Hawaii airports were among the six, he said.

Bateman suspects that the pilot, a respected and experienced captain with Korean Air, had aimed his plane, carrying 254 passengers, at Guam airport's DME on Nimitz Hill.

"I think the pilot thought the DME was on the field," Bateman said.

The crew of Flight 801 also questioned whether the glide slope worked until the end. Electronic interference is suspected for leading the captain to believe the glide slope worked.

"Flight 801 was at the wrong place at the wrong time, in a dark place on a rainy night," Bateman said.

The pilot and crew still apparently ignored two altitude warnings on the plane, for which no one has provided an answer.

Woodburn recommended that airlines intensify their flight training and equip their planes with advanced terrain warning systems.

Crews need easy-to-read charts clearly depicting terrain, he said. Pilots need to improve their crew briefings for takeoffs and landings, and flight crew duties should be better allocated.

"The most important factor of safety is an airline's management culture," Woodburn said. "Safety starts from the top."

The U.S. and Canada have the lowest rate for these types of accidents because of flight simulation training "that keeps (pilots) on the edge of their seats," he said. Many U.S. planes also have terrain warning systems.

As the hearings ended, lawyers for crash survivors and victims' families said they believed that Korean Air was being unfairly singled out as a responsible party and that the safety board steered the hearings away from placing any blame on the U.S. government or its contractors.

That could prevent lawsuits from being filed in U.S. courts, where a jury could award damages. In South Korea, there are no jury trials in such cases and those are slow to get to trial.

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