NTSB recovers cockpit voice recorder from airplane wreckage

MINA, S.D. (AP) -- Federal investigators said today they expect<br>to finish picking up the pieces of golfer Payne Stewart's shattered<br>Learjet by the end of the day, and confirmed they were looking

Thursday, October 28th 1999, 12:00 am

By: News On 6

MINA, S.D. (AP) -- Federal investigators said today they expect
to finish picking up the pieces of golfer Payne Stewart's shattered
Learjet by the end of the day, and confirmed they were looking at
three other crashes for similarities to this week's tragedy.

About two dozen people wearing plastic biohazard suits worked
today at the site where Payne's jet went down Monday after its
ghostly autopilot trip halfway across the country. The crater, in a
soggy portion of a cow pasture, was a jumble of black dirt
surrounded by grass and tall weeds.

All of the wreckage should be removed from the crater this
afternoon, Bob Benzon of the National Transportation Safety Board
said today. Investigators then will spend several days sorting
through the pieces in an airport hangar in Aberdeen to find parts
that may offer clues to what caused the tragedy.

Benzon said investigators are particularly looking for valves
and parts of the doors, windows and hydraulic components that could
have caused a rapid loss of pressure in the plane's cabin. Some of
the parts are only an inch or two across, he said.

"We're looking for little, little parts, like valves," he
said.

Investigators are trying to keep an open mind and not
concentrate too much on any one possible cause because that could
lead them astray, Benzon said. "We're really not specifying or
aiming at anything right now."

The cockpit voice recorder was found just before sundown
Wednesday, and it should arrive at the NTSB's Washington office
later today. Benzon said he hoped to get a report Friday morning
about the tape's contents.

"We're looking for unusual noises that may indicate some kind
of breach of the hull of the airplane," he said.

The recorder might also contain sounds from the plane's two
engines, possibly giving clues to whether the jets had mechanical
problems before the crash, Benzon said.

Benzon said the NTSB is looking into three other cases in the
past two decades in which Learjets have been involved in crashes
with similarities to Monday's crash.

According to published reports, they were apparently a 1983
crash in which a German-owned Learjet that flew from Vienna
disappeared into the Atlantic near Iceland, a 1988 crash in which a
jet inexplicably bypassed its Texas destination and crashed in the
mountains of northeastern Mexico, and a 1990 crash near Greenville
in western Ohio.

"We'll look at them. They may be for very different reasons,"
Benzon said today.

The jet crashed into a field near Mina on Monday four hours
after leaving Florida with Stewart and five other people aboard.
All were killed, and investigators are trying to determine how the
plane flew 1,400 miles across the country, apparently without
someone at the controls.

The Learjet had no flight data recorder that could provide
mechanical information, and the cockpit voice recorder has a
30-minute loop that usually records over itself. Officials do not
expect to hear anything about what happened when radio contact was
lost and the plane veered off course because that happened hours
before the crash.

But the voice recorder could have picked up sounds at the end of
the flight that could tell a lot about what was happening in the
plane, Benzon said Wednesday.

"We're still confident we can get some good information off
that tape," he said.

Government officials have said one possible explanation for the
crash is that the jet lost cabin pressure soon after taking off
from Florida, causing everyone aboard to die or lose consciousness.
That's why investigators are particularly eager to find valves in
the wreckage that regulate air pressure.

Benzon said investigators have learned that a device called the
left-hand modulator valve, which takes heated air from the engine
and runs it through the air-conditioning system to pressurize the
cabin, was changed on the plane Saturday.

If the left-hand valve failed, the one on the right engine
should have fed sufficient air into the cabin, he said.

Benzon said the valve was replaced Saturday to balance engine
thrust on the plane -- not because of any prior problem with cabin
pressure. After the valve was replaced, the plane
pressure-regulation system worked fine during a short flight on
Saturday, he said.

Benzon said he does not know whether such a valve has ever been
a factor in a crash.

Today in Houston, Stewart's peers on the professional tour
gathered on the first tee of the Champions Golf Club to remember
one of the game's most admired figures.

In a chilling start to the Tour Championship, a lone bagpiper
played "Going Home" as he marched through fog on the first
fairway.

"It's important not to lose sight of the most important thing
about Payne Stewart," said PGA Tour commissioner Tim Finchem. "He
was a man of great faith, a devoted, compassionate and most
energetic husband and father, and a man of tremendous generosity."