Cabin pressure alarm sounded on Stewart's plane

Voice recorder confirms investigators' suspicions

November 24, 1999|By KNIGHT RIDDER/TRIBUNE

DALLAS -- The cockpit voice recorder from golfer Payne Stewart's Learjet has confirmed what investigators suspected: Stewart and five others aboard likely died from lack of oxygen because the airplane lost cabin pressure.

The cockpit voice recorder, which picked up the last 30 minutes of sound inside the cabin, contained no voices, but there are sounds consistent with various alarms for cabin pressure and stall warnings, the National Transportation Safety Board stated yesterday.

The alarms were designed to go off when the air pressure inside the cabin reached the equivalent of 10,000 feet or higher. Most cabins are pressurized to maintain the equivalent of 8,000 feet or lower.

The fact that the alarms had sounded confirms to investigators that the crew likely had some warning of pressurization problems. That raises more questions about the jet's emergency oxygen system. Investigators found the oxygen bottle that was carried near the nose of the airplane, but its valve was broken off.

Investigators said it is possible for the emergency oxygen gauge inside the cockpit to read normal even if the oxygen is turned off at a valve on the bottle. The bottle can only be reached on the ground, and checking the valve is a part of the preflight checklist.

The charter jet carrying Stewart and five others crashed Oct. 25 near Aberdeen, S.D., after flying for more than four hours with no one at the controls. The airplane was en route from Orlando, Fla., to Dallas Love Field when it failed to make a scheduled turn. Military jets intercepted the Learjet and saw no sign of life aboard.

The safety board's statement said that various fragments of the aircraft, including parts of the pressurization and oxygen systems, have been taken to several manufacturers for examination.

The statement said that investigators are interviewing passengers from earlier flights and pilots who previously flew the aircraft to see if they had noticed anything awry.

Officials also are examining the operating records for the airplane, as well as the crew experience and training. Investigators have said that the captain of the flight had 37 hours of experience in the aircraft and that the co-pilot had about 250 hours spread among several business jets.

The investigation will likely take a year, but officials said they hope to make their initial evidence and investigative material available to the public early next year.

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