Quick changes urged for rudders on 737s Safety board hints that jet falls short of standards


SEATTLE -- The rudder systems on Boeing 737 commercial jets do not provide the same level of safety as similar passenger aircraft, the National Transportation Safety Board declared yesterday.

In one of its most vocal criticisms of the world's most widely used commercial jet, the NTSB also implied that existing 737s would not meet today's federal certification standards.

It called on the Federal Aviation Administration to speed plans to order newly designed rudder control systems on all 737s.

Both the FAA and Boeing maintained yesterday that the worldwide fleet of 2,790 737s meets federal safety standards and are among the safest aircraft flying.

Tom McSweeny, director of aircraft certification for the FAA, said his agency plans to issue a formal order on 737 rudder changes within the next two months.

He called the FAA's two-year timetable for replacement of the rudder power control units "aggressive."

The redesign is intended to prevent jamming or reversal of the rudders that could trigger Boeing 737s to roll over suddenly during flight.

The rudder is the movable flat panel in the vertical tail section that helps direct an airplane from left to right. The power control unit, which operates similarly to power steering in a car, converts the rudder pedal movement from the cockpit into hydraulic power to move the rudder.

NTSB Chairman Jim Hall recommended that the FAA require the "expeditious" installation of a redesigned main rudder power unit in all 737s.

The NTSB also urged the FAA to require additional training for flight crews in dealing with sudden rolls caused by unexpected rudder movement on the airliners.

The NTSB's actions may indicate the board is getting closer to concluding that a rudder malfunction contributed to the 1994 crash of USAir Flight 427, which plunged into a ravine in Pittsburgh, killing all 132 people aboard.

A similar problem is suspected in the 1991 crash of United Airlines Flight 585 at Colorado Springs, Colo., which killed all 25 aboard.

Pub Date: 2/21/97

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