Airliners Often Periled by Unexpected Winds : Aviation: Treacherous forces have caused jet crashes. The area of Colorado disaster is notorious for them.

The jetliner gliding toward touchdown at Denver’s Stapleton Airport was still 75 feet above the runway, its crew fighting the wind to bring the 70-ton twin-engine passenger plane down for a soft landing, when a sudden wind shift brought it down like a runaway elevator--falling seven floors to a hard landing.

“I believe, if we had hit the disturbance a quarter mile from the end of the runway, that we would not have been able to recover before hitting the ground,” the co-pilot wrote in a report on the 1986 incident.

Other pilots have encountered similar alarming weather conditions in that region. In fact, the eastern slope of the Rocky Mountains is notorious for the kinds of winds reported Sunday when United Airlines Flight 585 crashed on final approach to landing at Colorado Springs Municipal Airport.

The cause of the crash that killed all 25 aboard the Boeing 737 was still under investigation Monday, but officials said the pilot had been warned of strong wind gusts just before the plane went down. The National Weather Service reported gusts of up to 32 m.p.h.

Such treacherous forces, including the violent condition called wind shear, which can slam a plane into the ground, are potential safety threats to aircraft of all sizes--especially during the critical phases of landing and takeoff.

They are not limited to the Rocky Mountain region. Wind shear was blamed in part for the crash of a Delta L-1011 landing at Dallas in 1985 and the crash of a Pan Am 727 on takeoff from New Orleans in 1982, for example.

A Times review of aviation safety reports filed with the National Aeronautics and Space Administration by airline pilots who encountered severe weather problems disclosed numerous harrowing tales of their airborne struggles with some of the most powerful forces of nature. The records were obtained through a Freedom of Information Act lawsuit.

Among the samples of dangerous encounters was the experience of a jetliner crew landing at Newark, N. J., on a windy winter night. At 100 feet above the ground, the craft’s instruments indicated an abrupt loss of air speed, a condition typical of wind shear. The plane began to drop.

“Maximum power was applied to arrest sink rate,” the captain wrote in a report on the incident. But the plane bounced onto the runway before roaring back into the sky to complete a second, less eventful, landing.

At Salt Lake City, a Boeing 727 on approach to landing encountered such severe wind shear that the plane was descending rapidly through the 500-foot level even with the engines set near climb power.

“That was enough for me,” the captain’s report noted. “I executed a go-around.”

In fact, the crew had to make three landing attempts before getting the plane safely on the ground.

Last year in Portland, Ore., a jetliner was within 100 feet of touching down on the runway when wind gusts lifted the right wing, forcing the crew to abandon its landing after fighting unsuccessfully to keep the plane on course.

In Louisville, Ky., a 125-ton jetliner struggled against the wind to get its landing gear on the runway after encountering wind shear at 60 feet above the ground. The big plane stayed at 60 feet far down the runway before finally touching down a mile beyond the normal landing threshold.

A Boeing 747 inbound to Kona, Hawaii, made four unsuccessful attempts to land after hitting low-level winds that jeopardized safe control of the jetliner. The crew first noticed the wind problem at an altitude of 400 feet, less than a mile from the runway, when “we experienced an updraft which could be heard on the fuselage.”

In Florida, wind shear at the Orlando airport drove a landing jetliner onto the runway so hard that the wingtips scraped on the ground and one engine mount broke. And, at Pensacola, wind shear on takeoff forced the nose of a jetliner up at an alarmingly steep 30-degree angle that took both captain and co-pilot to overcome by pushing together on the control wheel.

And, in one report filed after a flight to Colorado Springs in the summer of 1988, a 727 crew expressed gratitude for the airfield’s low-tech wind detection device: a windsock.

The crew said that “it may have saved many lives by indicating a wind-shear condition that was not yet detected by the airport’s low-level wind alert system.”

Times statistical analyst Maureen Lyons contributed to this story.