Science: The Dangers of Quiet

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A jetliner taxis out to take off on runway 31 L* at New York's Idlewild airport. Radioed advice from the ground control crackles in the crew's ears: "In the interest of noise abatement, do not delay turn to 290°." Beside the taxiway, a blunt sign reminds the pilot again of the noise-controlling turn. The reminder is unnecessary. He knows that the moment his wheels leave the ground he must transmit a report to a company sound truck stationed in line with the end of the runway, and he must start a countdown: "Five, four, three, two . . ." At the count of two, he will ease his thrust levers (throttles) back and reduce power; all four engines will slow to comparative quiet as he glides over the truck. Hopefully, he will not register too much noise on the recorders that the Port of New York Authority has nearby.

As he climbs away from Idlewild, the pilot can spot beneath his wings row upon row of houses—a familiar sight close to the borders of most U.S. jetports. And the pilot knows that the noise abatement procedures that bugged him all through the tense (and potentially dangerous) moments of takeoff have only one purpose: to make life more pleasant in those residential areas. But last week representatives of the Airline Pilots Association, and of the engineers who fly with them, were protesting in Washington to Senator Mike Monroney's Aviation Subcommittee. Noise abatement, they argued, may be a blessing to an airport's neighbors; it is a menace to anyone who flies.

Apt to Get Caught. The modern jet is a nightmare of complexity. Pilot, co-pilot and engineer are busy during every split second of takeoff—watching instruments, managing flaps and other control surfaces, nursing the engines, checking visually for other planes, and watching for birds that might get sucked into a jet intake. Noise abatement rules only add to their burden at the touchiest moments of flight.

No commercial airline pilots are claiming that any single noise abatement rule makes flying dangerous. But bit by bit, say the pilots, noise abatement procedures are chipping away at their margin of safety. Long training urges that they take off into the wind and climb to altitude on a straight course under full power. Noise abatement often requires them to take off downwind, to climb too steeply, to make turns at minimum altitudes and air speeds. Cutting power for the sake of quietness reduces air speed also, just when a plane needs every boost it can get. As it is practiced today, says Edward Bechtold, a safety expert of the Airline Pilots Association, "noise abatement is like a married man going out with other women. If he does it long enough he's apt to get caught."

Price of Safety. As the commander of his airliner, every captain realizes that he is the ultimate authority on its safety. Theoretically, he may ignore any antinoise regulation that he considers dangerous. But the pressures to comply are considerable. Airports are continually harassed by their noise-sensitive neighbors, and the pilot who violates a rule for safety's sake may well live to regret it. The airline he works for may be reprimanded for a loud takeoff recorded on the airport's monitors. At some airports, of fending lines have learned that the price of safety is to be forbidden to take off during certain hours.