Boeing's Big Fix

After years of debate following two puzzling crashes, the Federal Aviation Administration Thursday ordered the installation of redesigned rudders on all Boeing 737 passenger jets, reports CBS News Correspondent Transportation Correspondent Bob Orr.

Also announced Thursday were new emergency procedures for pilots of 737s and new maintenance procedures for the plane, which boasts safety ratings twice the industry average.

The changes represent one of the largest fixes ever ordered by the FAA. They affect the world's most popular airliner: with 3,000 737s in service, one takes off every five seconds somewhere in the world.

The FAA made the order to guard against a rare, but potentially catastrophic, failure suspected in fatal accidents in 1991 and 1994.

A USAir crash outside of Pittsburgh in 1994 that killed 132 and an earlier United Airlines crash at Colorado Springs, Colo., in 1991 in which 25 perished have puzzled investigators. Both planes suddenly plunged to the ground.

Crash investigators suggested the 737's control valve could cause the rudder to unexpectedly jam in the opposite direction from that intended by the pilot, causing the plane to suddenly go out of control.

Prior to what was announced Thursday, the FAA and Boeing had agreed on earlier changes to the rudder system, and officials said they have had no reports of rudder problems since they were implemented.

However, an April 1999 National Transportation Safety Board report found that "even with these changes, the 737 series airplanes remain susceptible to rudder system malfunctions that could be catastrophic." The FAA commissioned a special engineering board to study the problem in May 1999, and it recommended the changes this April.

Until then, the FAA and Boeing had staunchly resisted calls for a complete makeover. Even now, Boeing insists the redesign, which will cost the company some $250 million, doesn't address a pressing safety issue.

Allen Bailey, chief engineer of safety and certification for the most widely-used airliner in the world, said that changes are "an enhancement above and beyond that to ensure the safety of this aircraft for the next 20 to 30 years."

"We are not fixing a safety problem," said Bailey. Rather, he said, these changes will maintain the 737's safety over the remainder of its service life.

The FAA echoed Boeing's description of the repairs as precautionary.

"When you look at the sheer size of the 737 fleet, the number of airplanes that are flying, and how many are going to be flying over the next 30 to 40 years, it compels the highest level of safety we've ever made for any airplane," said the FAA's John Hickey.

The rudder is at the rear of the plane and controls the vehicle's leftward and rightward movement. On the 737, it's controlled by pedals operated by the pilot or co-pilot. The pedals move cables that twist a vertical iron rod in the rear. That rod then activates a device that moves the rudder in one direction or the other.

The change envisioned will install two rods instead of one so that a problem with one rod won't impair the whole system—what Bailey called "a mechanism that allows for an override in case of a jam."

Bailey said the redesign was the best technological change that could be made that would allow Boeing to "keep it reasonable and rational in terms of the retrofit."

In addition to the redesign, a new set of emergency cockpit procedures for dealing with a rudder problem on the 737 has been developed and will be announced with a few weeks, a Boeing spokeswoman said. Bailey said also Boeing would compare 737 maintenance procedures to those used for later generation planes and update the 737 guidelines where necessary.