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Theories Abound Months After USAir Flight 427 Hurtled to Earth

January 1, 1995 GMT

PITTSBURGH (AP) _ Frequent flier William Meggs has a theory about what made USAir Flight 427 roll left and dive nearly four months ago, killing all 132 people aboard.

``The FAA took my name and phone number and said, `Somebody may want to call you,‴ said Meggs, who lives in Greenville, N.C. ``They did not.″

Meggs is in company with at least two pilots, a handful of lawyers and a professor of mechanical engineering. They all have theories _ and one feeling in common with investigators and victims’ relatives: frustration.

Since Flight 427 went down near Pittsburgh International Airport the night of Sept. 8, federal investigators have picked through twisted metal from the Boeing 737 and studied crash simulations on computer screens.

The lack of survivors has made their task tougher than usual. So has a shortage of data from the tape-recorded cockpit conversation and the electronic record of the plane’s systems.

The evidence points to a problem with the rudder, but no one is ready to name the crash’s cause.

That infuriates Dennis Dickson of Glenwillard, whose wife was killed in the crash. ``Planes just don’t fall out of the sky,″ Dickson said.

Officially, the National Transportation Safety Board is examining all ideas, but investigators seem to have discarded three major theories, all focused on the plane’s roll to the left.

First to go was the notion of a bomb.

The bomb idea came about because Flight 427 carried an unusual passenger, drug informant Paul Olson, who spent his last day talking to federal prosecutors in Chicago. However, even with the FBI’s help, investigators failed to uncover evidence of sabotage.

Next they focused on the possibility that the jet’s right engine was accidentally thrown into reverse when its thrust reverse actuators switched on at the wrong time.

Workers at the crash site found four of the right engine’s six actuators, which are meant to slow the plane during landing. Three were in working position, two were not, and investigators now believe the impact jolted the first three on.

On to Theory No. 3: swirling air. Carl Vogt, a member of the NTSB, said another jet 4.1 miles away created a wake that could have wrested control of Flight 427 from its crew.

Norman Chigier, a professor of mechanical engineering at Carnegie Mellon University, has studied wake vortexes and says a jumbo jet’s vortex can seize planes as far as five miles away.

The vortex theory was never publicly rebutted, but it seems to have been overshadowed by the board’s current thought: It was something about the rudder.

``Everything keeps pointing to the tail,″ a source close to the investigation told the Pittsburgh Post-Gazette.

Two facts support the rudder theory:

_ A major part of the jet’s rudder system, the power-control unit, was replaced in 1993 with a rebuilt part that had been overhauled because it leaked.

_ Hydraulic fluid in the power-control unit was dirtied with tiny bits of rubber and metal.

And two pilots have come forward with stories that bolster the rudder theory. Both managed to avoid accidents in planes that behaved like Flight 427, and both times rudder problems were to blame.

John Sullivan, a pilot for United Airlines, told Aviation Daily that as a military co-pilot in 1968 or 1969, he experienced a sudden roll in a C-141.

He believes the reason his rudder controls suddenly went into reverse was a mechanic’s poor adjustment of one screw in a rudder actuator valve.

Ray Miller of Continental Airlines was flying a Boeing 737-300 in April when it rolled violently to one side, The Seattle Times reported.

The Boeing Co. found rudder problems in two places: the yaw damper that compensates for oscillations of the plane’s tail, and a rudder actuator’s power-control unit.

Even without any definitive answers, lawyers for bereaved families are heading to court with assertions that USAir, Boeing, or some combination of the two is at fault.

Meggs, who travels to or from New York every month, sees similarities between what happened to Flight 427 and a flight he was once on that dived toward the ocean for at least three seconds.

The culprit in that fright was a malfunctioning autopilot, and he wonders if the same thing may have sent Flight 427 hurtling to earth.

Meantime, he’s taking Amtrak more lately. And when he flies, he flies American Airlines.