Salt Lake air travelers shouldn't experience delays because of safety concerns with the rudder of the popular Boeing 737 aircraft, according to the plane's manufacturer and two airlines.
The National Transportation Safety Board declared Wednesday that rudder reversal led to the September 1994 crash of USAir Flight 427 outside Pittsburgh, the 1991 crash of United Airlines Flight 585 near Colorado Springs, Colo., and an incident in 1996 where pilots of an Eastwind Airlines flight struggled to control the plane as they tried to land in Richmond.All 132 aboard the USAir plane were killed, as were the 25 people on the United flight.
The board declared that the current design of the rudder system is not "reliably redundant," and asked the Federal Aviation Administration to order that the rudder system must be redundant. Boeing Corp., which builds the 737, said it is already taking steps to improve safety.
"We've made a design correction or improvement," said Boeing spokesman Russ Young, Seattle. The improvement takes away the possibility of rudder reversal, he said.
All of the new generation 737s have the correction, and the airplane maker is taking steps to fix rudders in older (or "classic") 737s.
"We're currently retrofitting the world fleet to take out that problem. Under FAA mandate, that work's got to be done by August 1999."
He is not aware that any airlines will have to change scheduled flights to make fixes. In the NTSB finding Wednesday, "there was no indication there was anything urgent that was going to disrupt travel."
That means any corrections can be folded into normal maintenance schedules.
Delta Air Lines spokesman Tracy O'Donnell, based at company headquarters in Atlanta, said changes to the rudder assembly and training procedures have been made since the 1994 accident. One of Delta's hubs is at Salt Lake International Airport.
"Boeing has developed a number of recommendations to prevent any possibility of rudder reversal within this 4 1/2 years," he said.
Among these are recommendations to improve the plane's control of yaw, or unwanted tilting; to step up the plane's damper system, which reduces the severity of shifts in direction, and to increase reliability, he said.
Also, the manufacturer advised airlines to add a "rudder pressure reducer" to limit turning when full movement of the rudder is not required, he said.
"The industry has responded to Boeing's findings throughout this whole thing," O'Donnell said. "In fact, pilots today are trained to react to possible malfunctions and are prepared to respond to events should the airplane divert from its normal attitude."
The fixes have been made throughout the past 4 1/2 years, he said. There is no need to stop flying certain planes.
The 737 is not the mainstay of Delta's fleet. "We have more 727s than 737s," he said.
"But we do have them (737s), and we have been doing the changes. . . . We do believe the 737 is a safe airplane, and with the FAA-mandated rudder hardware and cockpit procedure changes, now being accomplished on the 737, it has been made even safer."
However, he added, he does not know what the FAA will say in the future, so he cannot predict if further changes will be needed. "But at this point, no," he doesn't think any will be needed.
Carol Pearson, spokeswoman for Southwest Airlines, said maintenance shouldn't affect the airlines' schedule.
"Well, when it comes to any kind of airworthiness directive . . . Southwest always fixes those things or interchanges those parts when we aren't flying the aircraft," she said.
Pearson, based in Southwest's headquarters in Dallas, said any future changes that are ordered "really wouldn't affect our service. We do all of our maintenance during the evening when we don't have service."