Short breaks 777s' panes

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SOURCE: Long Beach Press-Telegram
http://www.presstelegram.com/Stories/0,1413,204~21478~1681008,00.html

Short breaks 777s' panes
Windshield cracked three times this year on Boeing-made craft.
By AP

WASHINGTON Alitalia Flight 610 was over the Atlantic on its Rome-to-New
York run last July when the Boeing 777 seemed to shudder. Passengers
smelled smoke.

The cabin crew ran up to the flight deck as passengers screamed, said
Bruce Northrup, a New York City banker returning from a wedding with his
wife and 15-year-old son. "People were yelling, 'Tell us what's going
on,'' he said to the Associated Press.

The twin-engine jet made a U-turn and began descending gradually. The
pilot told the 300 or so frightened passengers they had a "serious
technical problem' and were headed to Shannon, Ireland, a half-hour
away. He also told them to calm down.

They were quiet, but not calm, for what turned into a very long 90
minutes, Northrup said. After a safe emergency landing, passengers saw
what had caused the problem: a windshield covered with cracks.

"That window looked like something out of an automobile junkyard,'
Northrup said.

Boeing officials traced the problem to faulty wiring in a window heater.
At least two other Boeing 777s have experienced the same problem in the
past year, the AP has learned. All landed safely and no one was hurt.

Experts say three similar incidents in one year is unusual for an aircraft.

The 777, Boeing's newest, largest twin-engine jet, is among the most
modern in the commercial fleet. It entered service in 1995, carries up
to 550 people and costs between $153 million and $231 million each,
depending on the model. There are 138 registered in the United States,
according to Federal Aviation Administration records.

Their windshields, made of three layers of glass, acrylic and epoxy, can
get brittle in the cold, thin air at cruising altitude seven miles up.
They're warmed by a heater to stay elastic. The wires on the three
planes that suffered cracked windshields loosened and shorted out.

On the Alitalia flight, the short caused a small fire and the innermost
layer of the window cracked, Boeing spokeswoman Liz Verdier said.

The flight crew put out the fire with an extinguisher in three seconds
and then brought the plane down to 10,000 feet. That reduced the
difference between the pressurized cockpit and the thin air outside,
said Bill Waldock, aviation safety professor at Embry- Riddle
Aeronautical University in Arizona. The danger at high altitudes is that
the windshield could shatter and loose items or people could be sucked
out, though that's never happened on a commercial flight.

Boeing has sent a directive to airlines instructing them how to tighten
the wire connections. Boeing also is developing circuit breakers that
will prevent sparking and the window from overheating, Verdier said.

Fires can be a bigger safety issue than cracked windows.

"Electrical fires are kind of nasty because they're so hot,' said
Waldock. "But as long as that's all there is, it's the easiest to stop.'

John O'Brien, safety director for the Air Line Pilots Association, said
the wiring problem in the 777s isn't a major concern because the
embedded filaments in the windshield are isolated from other combustible
materials.

FAA officials said Boeing is taking appropriate action.

"Anytime there's a fire, there's a concern to us,' FAA spokesman Paul
Takemoto said. "But cracked windshields rarely affect the safety of the
aircraft.'

Most windshield damage is caused by planes striking birds. Between Jan.
1, 1990, and last Dec. 31, there were 442 such incidents recorded by the
FAA's National Bird Strike Database. However, database manager Sandra
Wright estimates 75 percent of bird strikes go unreported.

Waldock said it's extremely rare for a cracked windshield to cause a
major problem for pilots. If the crack is serious enough the pilot
simply descends and makes an emergency landing at the nearest airport,
as the Alitalia crew did.

Waldock said to his knowledge the most serious incident involving a
windshield occurred 13 years ago over England when the captain's front
panel of a BAC- 111 cracked and blew out as the plane was cruising at
20,000 feet.

--
David Mueller / MRY
dmueller7@xxxxxxxxx
http://www.quanterium.com

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