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FAA Will Order Redesign of Boeing 737 Rudder Blamed in Two Crashes

By Ricardo Alonso-Zaldivar

The Federal Aviation Administration announced Thursday that it will order a redesign of vital controls on the world’s workhorse airliner -- the Boeing 737 -- to prevent an elusive failure that can cause a catastrophic crash.

The action came after an FAA-appointed expert panel concluded that previous fixes of the plane’s rudder ordered by the agency had not addressed more than a dozen possible ways in which it could fail.

It may take the better part of a decade to design and install the new rudder controls on nearly 4,000 aircraft, but Boeing insisted Thursday that 737s are safe, saying the problem is rare and that the previous fixes eliminated the most dangerous of the potential failures.

Allen Bailey, Boeing’s chief engineer for the 737, said the planes do not pose a safety risk to consumers. “I’m going to put my family on one in about a month,” he said.

Though the 737’s overall safety record is twice as good as the industry average, rudder problems have been blamed for two disasters that killed 157 people.

USAir Flight 427 went down Sept. 8, 1994, near Pittsburgh, killing all 132 people on board. United Airlines Flight 585 crashed March 3, 1991, near Colorado Springs, Colo. The 20 passengers and five crew members all died. Both crashes occurred during the landing approach.

In each case, investigators blamed the rudder, a vertical surface on the tail that helps pilots steer the aircraft. The failure of a component is believed to have caused the rudder to veer in the opposite direction intended by the crew -- as if a driver were turning the steering wheel of his car to the right and the vehicle swerved left. Jetliner pilots use the rudder primarily to compensate for crosswinds when they are landing or taking off.

Boeing’s Bailey said the company already has begun redesigning the rudder controls. The new unit, a variation of one used on the company’s 757 model, will cost an estimated $50,000 to $60,000 per plane. The price of a new 737 can range from $38 million to $64 million, depending on the model.

The redesign essentially would increase the redundancy of the rudder controls, preventing a single-point failure from causing problems.

Boeing plans to install the redesigned components in new aircraft beginning in 2003, when it also would start refitting 737s already in service.

Safety board Chairman Jim Hall said in a statement that the conclusions of the FAA’s expert panel “essentially confirmed our findings ... that the Boeing 737 rudder control system has numerous potential failure modes that represent an unacceptable risk to the traveling public.”