80 mph wind forecast in LR as jet neared

By KIMBERLY GILLESPIE

LITTLE ROCK — A severe thunderstorm warning, predicting winds as high as 80 mph, was issued for Little Rock, the final destination of American Airlines Flight 1420, just 10 minutes after the plane left the Dallas/Fort Worth International Airport.

Though steady winds were measured at only 43 mph at Little Rock National Airport, Adams Field, as the plane approached the runway, wind gusts of up to 87 mph were recorded there just six minutes after the plane crashed.

Heavy rain and hail larger than three-fourths of an inch inundated the area at the time of the accident, and fallen trees and limbs littered nearby yards and roads.

Of the 139 passengers and six crew members, nine were killed, and 86 were treated at local hospitals. Among the dead was Capt. Richard Buschmann, the plane's pilot.

What Buschmann knew about weather conditions and why he decided to land is unclear. Federal investigators have not released voice flight records or other data from the crash.

However, the wind could have been a factor.

At 10:55 p.m. Tuesday the Kansas City Aviation Weather center of the National Weather Service issued a severe weather warning for pilots on its federal communications system.

The center issued aviation advisories for all domestic flights in the United States and over the Atlantic and Pacific oceans.

The warning stated that a storm was heading toward the Little Rock airport at 30 mph, and it could involve winds of 30-80 mph with 2-inch hail. The warning extended through 12:55 a.m. Wednesday.

"It was pretty severe," said Jim Henderson, deputy director at the Aviation Weather Center in Kansas City, Mo. "We don't issue this unless we believe that it's dangerous for aircraft activity. At the top level, that would have been hurricane-force winds."

The alert is called a Convective SIGMET, which stands for significant meteorological advisory. It warns of significant thunderstorms in an area.

"We basically put this onto a federal communications system, and it is distributed by the Federal Aviation Administration," Henderson said. "Routinely, it would be received by the air traffic control center. We have to assume they got it. But I can't tell you whether they got it or not."

Before he took off from the Arlington, Texas, airport, the pilot would have had a weather briefing from American Airlines, which has a forecast center for its pilots, Henderson said. "That's part of the briefing, where the SIGMETs are and where bad weather is located."

The decision to land or take off can depend on whether there is "a head wind, tail wind or crosswind involved." The size and type of plane also is considered, not just the wind gusts.

"These are all factors that play into a decision to land," Henderson said. "It gets down to pilot discretion."

At 11:14 p.m. Tuesday the National Weather Service in Little Rock issued a severe thunderstorm warning for Pulaski County until 12:20 a.m. Wednesday.

"Pilots know that the criteria for a severe thunderstorm warning is winds 58 mph or greater and hail [of] three-fourths inch or greater," says George Wilken, science and operations officer at the weather service.

"We would issue a terminal aviation forecast that goes directly to the tower. They would get it within a minute."

At 11:51 p.m. Tuesday Flight 1420 crashed as it attempted to land at the Little Rock airport. Winds were approximately 43 mph, according to airport data.

At 11:57 a.m. Wednesday winds reached 87 mph at the Little Rock airport.

Barry Beck, chief flying instructor at Central Flying Service in Little Rock and a pilot for 10 years, speculated Wednesday that wind shear could be at fault.

Wind shear is a change in the force or direction of wind from one atmospheric level to the next. As Beck explained it, the wind the plane was flying into as it approached Adams Field may have been significantly stronger than the wind it faced as it lowered to the ground for landing. Or the wind above may have been blowing against the plane while the lower air may have been blowing behind or against the plane.

Either way, Buschmann may not have been able to adjust the plane's speed quickly enough to compensate for the difference before touching down.

Paul Takemoto, FAA spokesman said the Little Rock airport uses a low-level wind shear alert system. Six sensors 50-150 feet high and placed in different parts of the airfield measure winds and trigger a wind shear alert if there is a wind difference of 13 knots from one sensor to another. Air traffic controllers then relay that alert to pilots, Takemoto said.

"FAA air traffic controllers relay weather information to the pilot, but it is up to the pilot as to whether to make the landing or not," Takemoto said.

Takemoto would not comment on whether the alert went off.

Beck said pilots can't always rely on reports from traffic control during storms because of the volatile atmosphere.

"It's one of the most challenging things that pilots have to deal with," Beck said. "They get information from the air traffic controllers, but the conditions are always changing and the information they're getting may not always be accurate."

Storm chaser George Hoelzeman has a different theory for the cause of the crash.

Before the pilot was ready to land, Flight 1420 could have been pushed down by a down-burst, air that rapidly descends beneath a thunderstorm.

"That could explain why he couldn't stop fast enough, if he wasn't prepared to make a landing," Hoelzeman said.

Hoelzeman notified the National Weather Service about 76 mph gusts at his home in the Park Hill area of North Little Rock about 11:30 p.m.

Hoelzeman wasn't the only storm chaser out Tuesday night. Ham radio operator Gary Sikes also of North Little Rock was watching the "spectacular electrical show" -- lightning -- when he heard other operators talking about the crash.

"I got there about 20 minutes after it happened," Sikes said. "I got about as close as you could get in a car, and through the rain I could see the smoke billowing. The fire was already out."

Information for this article was contributed by Mary Hargrove of the Arkansas Democrat-Gazette.

Copyright © 1999, Arkansas Democrat-Gazette, Inc. All rights reserved.