By KATE SHEEHY

December 3, 2001 -- American Airlines was warned four years ago that its

pilots were trained to dangerously over rely on rudders to the point of

potential structural weakening - a possible factor in the fatal crash of

Flight 587.

In a 1987 memo from safety experts at Boeing and Airbus, American was told

that training its pilots to overuse the crucial rudder in turbulent

situations can "lead to structural loads that exceed the design of the fin,"

according to several published reports.

U.S. aviation officials are probing what caused the tail fin - which is

attached to the rudder - of the doomed American Airlines Airbus A300 to

shear off shortly after takeoff from Kennedy Airport under clear skies Nov.12.

The plane, headed for the Dominican Republic, crashed moments later in the

Rockaways, killing all 260 aboard and five more on the ground.

Probers have reportedly been focusing on the violent shaking of the plane

after it encountered the second of two wakes from other planes - and whether

the Flight 587 pilots may have overcompensated as they tried to right the

plane through the use of the rudder.

In its defense, American Airlines insists that its pilot-training program

was revamped in 1999 to address the concerns of overuse of the rudder.

And both pilots aboard Flight 587 received the new instruction, which moves

away from relying too heavily on the rudder during turbulent situations, an

airline spokesman says in this week's edition of Time magazine.

In addition, regardless of how the rudder may have been moved, the tail

shouldn't have sheared off the way it did, some pilots and American

officials have said.

The National Transportation Safety Board is continuing to investigate the

cause of the crash.

A structural or mechanical failure has not been ruled out.

The baffling case has led the NTSB to call in scientists at NASA, who are

experts in the kind of nonmetallic composite materials used in the Airbus tail.

Both the plane's rudder and fin are being sent to NASA's research center in

Hampton, Va., for further study.

"We know the tail came off in flight, and we're trying to find out why it

happened," NTSB spokesman Ted Lopatkiewicz said.

Also being examined are the jet's engines, which fell off before the crash.

Meanwhile, the Federal Aviation Administration has ordered the inspection of

all Airbus A300-600 and A310 planes, which have similar tails. France is

conducting similar inspections.

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