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Crew's Confusion Is Cited in Colombian Plane Crash

September 28, 1996|ROBERT L. JACKSON | TIMES STAFF WRITER

WASHINGTON — The crash of an American Airlines jet in Colombia last December resulted from "inadequate use of automation" by its two pilots, who became confused by the aircraft's computer-assisted navigation system, a Colombian government investigation concluded Friday.

The inquiry into the accident that killed 159 people ruled out engine trouble or mechanical failure. But it raised serious questions about the proper use of cockpit automation, a subject that U.S. officials said would be studied by the National Transportation Safety Board.

Only four passengers survived when the Boeing 757 crashed into mountains during a night approach to the Colombian city of Cali.

The Colombian government, assisted by U.S. investigators from the safety board, concluded that members of the crew failed to discontinue their approach into Cali because they did not recognize their true position.

Among "probable causes" of the crash, the report listed "the lack of situational awareness of the flight crew regarding vertical navigation, proximity to terrain and the relative location of critical radio aids."

About 11 seconds before the crash, the first officer took direct command of Flight 965 from the computer when he saw that he was too close to a mountain. But his efforts to climb above the top of a ridge failed by 200 feet, investigators said.

The report said "confusion in the cockpit" had resulted largely from inconsistencies between navigational codes on aeronautical charts and codes programmed into the jet's computer.

The findings confirmed earlier reports that the captain had entered a one-letter computer command that incorrectly directed the plane toward Bogota, 132 miles in the opposite direction, rather than toward Cali. On most South American aeronautical charts, the codes for Bogota and Cali are identical: the letter R. But they have different letters in most computer databases.

When the captain typed in the wrong letter, it "led to the turn toward high terrain," a mistake the flight crew discovered too late, the report concluded.

The Federal Aviation Administration has since issued a bulletin to all airlines warning them of inconsistencies between some computer databases and aeronautical charts.

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