Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: TUESDAY, March 13, 1990 TAG: 9003133469
SECTION: NATIONAL/INTERNATIONAL PAGE: A/4 EDITION: EVENING
SOURCE: Associated Press
DATELINE: WASHINGTON LENGTH: Medium
The Federal Aviation Administration on Monday tentatively issued an "airworthiness directive" requiring modifications that the agency said would enable pilots to steer the plane even if hydraulic lines are severed in the plane's tail section.
The order, which becomes final after a period of several weeks for public comment, resulted from the July 19, 1989, crash of a United Airlines DC-10 at the Sioux City, Iowa, airport where it was making an emergency landing with 295 people aboard.
Investigation into the crash continues, but pilots said they lost hydraulic steering control after the plane's tail engine exploded.
The FAA order follows changes recommended in the airliner by its manufacturer, McDonnell Douglas Corp.
"The change would preserve enough hydraulic fluid following damage to the system to enable the flight crew to safely fly and land the airplane," the FAA said. Airlines would have six months to make the modifications in the 10-series of DC-10s and a year for all other DC-10 models.
Investigators in the Iowa crash have said they believe flying debris from the explosive tail engine failure severed all three of the jetliner's independent hydraulic systems that control flight.
The FAA-ordered modification would require devices in the hydraulic system to keep fluid from leaking out in the event the lines in the tail section, where the hydraulic systems come the closest together, are cut.
With the change, the pilot would still lose control over the rudder, which turns the airliner, and the elevators, which control climb and descent. But other control surfaces, including the ailerons, which make it possible to keep the wings level, would remain operable, the FAA said.
Crew members of the United plane said their only means of steering the aircraft and controlling descent was to selectively accelerate the remaining wing engines.
The FAA earlier ordered an ultrasonic inspection of all DC-10 engine fan disks for a possible microscopic defect in the metal that investigators said may have caused the engine failure.
by CNB