Sifting Through the Wreckage

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A swirl of speculation quickly surrounded the crash. The day afterward, some witnesses reported having seen flames trailing from one of the plane's two engines. That possibility was discounted when the NTSB announced that the engines revealed no evidence of fire or early disintegration. Wind shear was also deemed a possible culprit. Abrupt wind shifts were responsible for the last major crash of a U.S. carrier, a Delta Air Lines Lockheed L-1011 jet in Dallas on Aug. 2, 1985. In Detroit, Flight 255 had been rerouted to another runway to avoid a gust of wind from a distant thunderstorm. Still another hypothesis concerned the baggage loading: investigators examined the possibility that too much cargo may have been placed toward the rear of the aircraft, tipping the center of gravity aft and causing the plane to go out of control.

But attention soon shifted to the wing flaps. The clue came from the plane's sophisticated flight-data recorder, the so-called black box (it is actually bright orange, for easy spotting) that monitors everything from airspeed to brake temperatures. It showed no indication that the pilot had extended the flaps. Nor did conversation between the pilots in the cockpit include a mention of the flaps during the preflight verbal checklist.

Such an oversight is almost unthinkable: a takeoff without extending the flaps, said Federal Aviation Administration (FAA) Spokesman John Leyden, is like driving off in a car without closing the door -- and far more dangerous. Yet such a lapse, notes University of Michigan Aeronautic Engineer C. William Kauffman, "would explain some of the things that were observed -- the aircraft using a lot of runway, not climbing very high, stalling."

But blaming the flaps may be premature. The plane's computerized warning system never alerted the crew that the flaps were not extended. At week's end a co-pilot of a nearby Northwest jet who said he observed Flight 255's ill- fated takeoff insisted that the slats and flaps on the plane were in the correct position.

Any finding at this early stage can only be tentative. The real work of the NTSB investigators is not on-site but in the lab. Investigators hope a study of the wings and of the actuators, hydraulic pistons on the wings, will conclusively show where the flaps were.

The ultimate determination of a "probable cause" is made by the full NTSB after a public meeting that may not be held for nine to twelve months. Whatever the cause of the Detroit disaster, the doubts and conflicting reports are unnerving for airline passengers and officials alike. Notes newly appointed FAA Administrator T. Allan McArtor: "You work so hard to build into your system safety margins, procedures, mechanisms to deal with the human frailty. When these break down, it just stuns you."