Retrofit ordered for Boeing 737, workhorse of Las Vegas aviation

James Wallace

Thursday, Sept. 14, 2000 | 11:27 a.m.

The Boeing 737 jet is a staple at McCarran International Airport with the top three carriers using it heavily on flights to and from Las Vegas.

Southwest Airlines, which has 154 daily departures from Las Vegas and is largest carrier at McCarran, has 333 of the twin-engine jets and opera the 737 exclusively.

Because the modifications are expected to occur during routine maintene cycles, the airline does not expect any delays or sched changes due to the FAA order.

The 737 represents half the fleet -- 61 of 122 planes -- the second-largest carrier at McCarran, America West Airli. The airline has 86 daily departures to 37 destinati from McCarran.

United Airlines, which has 39 flights a day tho Las Vegas, uses the 737 exclusively for its Shut by United flights to and from Los Angel San Francisco and Denver.

The Federal Aviation Administration is ordering the Boeing Co. to redesign the rudder system on its 737 and will require modification of its entire 1,500-plane U.S. fleet starting in July, a spokeswoman for the agency said Wednesday night.

Boeing will pay all the costs, a bill some aviation experts have said could easily top $200 million.

Airlines are likely to have at least five years to comply.

In the meantime, the agency next month will mandate additional training for pilots to handle an uncommanded movement of the plane's rudder.

The action comes after years of questions and debate about the safety of the rudder system on the world's most widely used jetliner. More than 3,000 737s are in service around the world.

Two fatal 737 crashes in the 1990s were blamed on a rudder malfunction.

"The rudder redesign will take this plane to the ultimate safety level," FAA spokeswoman Diane Spitaliere said in an interview.

She stressed that the 737 has an excellent safety record and the flying public should not be alarmed.

But the redesign will ensure redundancy in the 737 rudder-control system, she said. That was one of the recommendations made last year by the National Transportation Safety Board.

The FAA plans to brief reporters today.

Boeing will hold a news conference afterward. A company spokesman declined comment Wednesday night other than to note the 737's "outstanding" safety record.

The 737 has an accident rate that is half the industry average and the jet has the best safety record of any airplane in its class.

Boeing will pay for the redesign and the fleet modifications, Spitaliere said, though she could not confirm aviation experts' estimates of the cost.

The FAA will issue its order, in the form of an airworthiness directive, in July after Boeing has completed the redesign of the rudder mechanism and it has been certified, Spitaliere said.

The twin-engine 737 is the world's most frequently flown jet, with one taking off an average of every five seconds. The 737 fleet has about 100 million flight hours. About 3,600 planes have been delivered, with 3,200 still in service around the world.

The FAA can only order U.S.-registered operators to make the rudder modifications. Other countries, however, usually follow the FAA's lead. The fleet-modification work is likely to be accomplished during regularly scheduled maintenance.

Spitaliere said Boeing will have to incorporate the redesign on planes in production after the certification process.

In the meantime, the FAA will take more immediate action to make sure 737 pilots are better trained on how to deal with an in-flight rudder malfunction should one occur, Spitaliere said. She said existing 737 pilot training procedures, which were put into place after the fatal crash of a 737 near Pittsburgh in 1994, are inadequate.

Those procedures have been simplified, she said, and pilots can easily commit them to memory rather than rely on a manual.

The actions being taken by the FAA have been expected.

In April, a blue-ribbon group of scientists and engineers recommended that the 737 rudder system be redesigned to make it safer, and the FAA said at the time that it was likely to go along with the recommendation, even though the panel had not identified any immediate safety problems with the 737.

The group, formally called the Flight Control Engineering Test Evaluation Board, has been meeting in Seattle for more than a year, and includes scientists from NASA and the Defense Department.

Boeing people are on the team, but they came from the company's military Phantom Works program or from its Long Beach, Calif., division and had no previous involvement with the 737 rudder system. The group has worked in a Boeing-owned facility known as the integrated system laboratory at Boeing Field.

Boeing leased a 737-200 from Purdue University and fully instrumented the plane for flight testing. The university had acquired the jet to train mechanics.

The group's formation was one of the recommendations made last year by the safety board when it issued its final report on the probable cause of the USAir Flight 427 crash.

Board Chairman Jim Hall said at the time the 737 rudder system needed to be redesigned to make it "reliable redundant" like the ones on Boeing's 757 and 767 aircraft. The rudder is the movable part on a plane's tail that controls side-to-side movement.

Over the years, there have been many incidents in which 737 pilots have reported uncommanded rudder movements.

After the longest investigation in its history, the NTSB said a jammed rudder probably caused the crash of Flight 427 near Pittsburgh that killed all 132 people on the 737.

It also blamed a jammed rudder for the the 1991 crash of a United 737 near the Colorado Springs, Colo., airport that killed 25 people.

Since the two crashes, the FAA has issued several airworthiness directives to make the 737 rudder safer.

In 1997, the FAA ordered U.S. airlines to replace the rudder power-control units in 737s. The modification prevents a possible jam. Airlines finished that task in August 1999.

The FAA also ordered that a new yaw damper coupler and a hydraulic pressure reducer be installed on 737s. That work was supposed to have been accomplished by last month.

The hydraulic pressure reducer limits the amount of rudder deflection that can occur.