Warnings Sounded in Jet Before Fatal Crash in Aspen

Electronic warnings sounded in the cockpit a few seconds before a chartered jet from Los Angeles crashed while attempting to land at the Aspen airport last week, federal investigators said Friday.

Although such warnings alone are not indicators of an imminent crash, a veteran pilot said the pilots of the Gulfstream III jet may have had less margin for error than they realized.

“They may have gotten into an excessive angle and they didn’t even realize it,” said Lewis Aaronson, a retired airline pilot who has also flown Learjet aircraft.

The National Transportation Safety Board, which is investigating the crash that killed 18 people, said the two warnings were picked up by the cockpit voice recorder.

The NTSB issued a summary of the voice recorder tape, but no direct quotations from the pilots. Investigators said there was no sign that the pilots were grappling with a mechanical problem.

But they may have had some initial trouble spotting the runway as they made their approach using instruments. According to the summary, they asked the tower if the runway lights were all the way up, which they were.

The tower controller then asked if the crew could see the runway. The pilots said they could.

An electronic voice, part of a terrain collision avoidance system, alerted the pilots that they were 1,000 feet from the ground. The voice continued to call out the drops in altitude every 100 feet.

About 12 seconds before the crash, an electronic voice warned the pilots by calling out “sink rate.”

Aaronson said the warning means the plane was descending more quickly than normal. “Your terrain closure is well above the normal rate at that altitude,” he said.

Pilots can sometimes descend too quickly when they break out of the clouds and spot the runway. “There is a tendency when you break out into visual conditions to lower the nose and dive for the end of the runway,” Aaronson said.

About 200 feet from the ground, an electronic voice called out “bank angle,” indicating that the plane may have been turning too sharply.