A Fatal Case of Wind Shear

Black cumulonimbus clouds rolled in on New York City, darkening the afternoon sky up to nearly 40,000 ft. Lightning bolts darted above Manhattan's skyscrapers. Thunder sporadically overwhelmed the city's normal noises of traffic, subways and sirens. It would be a wet but cool rush hour, a welcome break in the summer's first siege of humid heat.

At Kennedy Airport's long runways along Jamaica Bay in Queens, visibility was two miles, the ceiling 5,000 ft.--both-well beyond landing and takeoff minimums. The arcs of lightning, terrifying to many air travelers, caused little concern among the air-wise. Lightning slips routinely off the skins of modern air: craft, rarely impairing vital controls or igniting the well-protected fuel tanks. J.F.K.'s radar picked up the thunderstorm's ominous hook-shaped rain cells. Rain itself poses no unusual problem for pilots. Yet real dangers lurked invisibly in this storm's particular pattern of high and erratically shifting winds. The airport control tower's landing logs and later explanations by pilots documented the elusive perils.

3:56 P.M. A Flying Tiger DC-8 cargo jet approached Runway 22-L. Suddenly, the unpredictable winds shook the 350,000-lb. plane. Pilot Jack Bliss fought to retain control. "Wind shear on approach," he warned the tower. "The wind pulls you down and turns you over ... you should close that runway." But he landed on it anyway, safely.

3:58 P.M. Eastern Air Lines Flight 902, a Lockheed Tristar jumbo jet, descended toward the same runway. It was caught in the same turbulence, measured at up to 90 m.p.h. Pilot Clifton Nickerson alerted the tower to the "wind shear and turbulence." Struggling, in his term, to "save it," he prudently pulled the huge craft back into the air and off to a safe landing at nearby Newark Airport. Some of his passengers grumbled about the "poor service."

4 P.M. Arriving from Helsinki, a Finnair DC-8 touched down uneventfully on Runway 22-L.

4:03 P.M. A small, private twin-engine Beechcraft Baron, more susceptible to wind conditions than the big airliners, landed on the same strip without difficulty.

4:06 P.M. Twenty minutes late on its nonstop run from New Orleans, Eastern's Flight 66 headed toward the same runway. A stretched version of the Boeing 727, its three jet engines mounted at its tail, the plane carried 116 passengers and a crew of eight. Its pilot, Captain John W. Kleven, 54, only minutes earlier had been advised by the tower of the complaint about wind shear made by Eastern 902's pilot. Unlike his fortunate predecessor, however, Kleven was unable to "save it."

Descending over sparsely populated marshland at the airport's northeastern edge, the blue-and-white airliner roared in, fatally low and short of the runway. Still a full 2,300 ft. from 22-L but otherwise on course, it struck a row of 22-ft. towers supporting the runway approach lights. It clipped three of them. Then, in what may have been a final valiant effort by the pilot to regain control, it momentarily cleared the next three. Finally, it plunged into four more.

The craft was ripped apart on impact, its pieces strewn over five acres. Its largest sections, including about 45 ft. of the rear fuselage, spun into a swampy field, caromed across Rockaway Boulevard, which would have been jammed with home-bound traffic an hour later, and ripped through a wire fence. The rear section came to rest upside down and afire.

Amazingly, two flight attendants, Mary Mooney, 28, of Tulsa, Okla., and Robert Hoefler, 29, of New York, managed to stumble out of the wreckage in a daze. They had been in the last row of seats. Twelve other passengers were found alive by rescue workers.

Mostly, the rescuers found only broken bodies. By week's end 111 persons had died, predominantly because of impact injuries rather than fire. Another ten were in critical condition. The death toll equalled the 111 deaths recorded in the crash of an Alaska Airlines 727 into a mountain near Juneau in 1971, until now the worst single-plane accident in U.S. aviation.

Lethal Force. What had gone wrong? With their usual dispatch and customary caution about premature conclusions, investigators from the National Transportation Safety Board launched an inquiry that will take months to complete. But their guarded comments indicated great skepticism that lightning had knocked the plane out of the sky, as was suggested by no fewer than 27 witnesses. Instead, the experts hinted that "wind shear" will almost certainly be cited as a major, if not the primary probable cause of the crash.

If so, another hazard to air travel will gain new prominence in the minds of millions of already nervous passengers. Wind shear carries a frightening connotation of lethal slicing forces, and with good reason. It is a highly unpredictable and violent weather phenomenon that results when opposing squall lines of high-velocity winds cross or collide. The result is a whirlwind, minitornado effect in which wildly thrashing air currents can throw even huge aircraft out of control when they are flying at relatively low landing speeds, generally around 180 knots. During the critical moments of landing, there is little time for a pilot to recover from such unexpected buffeting, and ground obstacles are often perilously close.

"We began denning wind shear and identifying it as hazardous only in the past decade," explains Charles Miller, director of safety seminars for the Flight Safety Foundation. "It is treacherous. An aircraft may be stabilized flawlessly on an instrument approach, with thrust setting, airspeed, flaps and rate of descent all coordinated. Then comes a vertical gust. Or a gust from the rear. A head wind suddenly becomes a tail wind, and the aircraft's rate of sink suddenly accelerates. Only recently have we begun to appreciate the variations and magnitude of wind shear."

Although wind shear is invisible to the eye, the conditions that make it probable can be spotted by radar and detected by weather instruments. Any violent thunderstorm, of course, raises a possibility of such dangerous air currents. But the problem in combatting this hazard is that it is capricious, its intensity is unpredictable, and to close down airports every time the wind shear possibility remotely exists would seriously disrupt air travel. U.S. investigators have, in fact, cited wind shear as contributing to the probable cause of only one previous accident: the crash of an Iberia Airlines DC-10 at Boston's Logan Airport on Dec. 17, 1973. In that case, the plane was severely damaged but no one was killed.

Facing Backward. Last week's tragedy at Kennedy, however, raises serious questions about the reaction of airport authorities, pilots and air traffic controllers to the wind-shear menace. In this case, at least two pilots had detected the danger and alerted the tower. But no move was made to close the affected runway. Although the ill-fated Eastern pilot had acknowledged his awareness of the danger, he might have been lulled into a belief that it had passed by the successful landing of the two intervening nights. At issue is a longstanding and sensitive dispute over who must decide whether or not to land. With their own lives at stake, as well as those of their passengers, pilots have long insisted on final authority over such decisions. Current federal regulations accord them that right. At each airport the Federal Aviation Administration's tower chief has the responsibility for closing specific runways or the entire field. Controllers are required to advise pilots of adverse conditions but cannot order them to seek another airfield. The Kennedy crash makes plain the need for clearer standards for determining when wind shear presents grave dangers, as well as tougher guidelines on what course to take when it does.

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