HALIFAX (CP) - Wiring that fed a controversial entertainment
system aboard
Swissair Flight 111 likely contributed to a fire that brought the
plane down
off Nova Scotia in 1998, investigators said Thursday.
The Transportation Safety Board didn't identify the exact source
of a fire
that led to a massive electrical failure aboard the MD-11
jetliner, but
concluded it was linked to the system.
In a 337-page report, the agency said the fire started when wire
arced above
the ceiling on the right side of the cockpit. The arcing - a
phenomenon in
which a wire's coating is corroded and can lead to sparking -
ignited a
flammable insulation covering, allowing the fire to race through
the plane's
wiring system.
"Investigators believe that this arcing
event on the entertainment system
wire was associated with the initial
arcing event," the agency said in a release.
"However, investigators could
not pinpoint this as the lead event."
The board said it had recovered 20
pieces of wire from the shattered remains
of the plane that showed melted copper,
indicative of arcing damage.
Vic Gerden, the agency's lead investigator,
said this was likely not the
only wire involved in the arcing.
"We strongly suspect that at least
one other wire was involved, either an
aircraft wire or another entertainment
system wire," he said in a statement.
Investigators also determined the pilots acted appropriately in
not trying
to land the plane immediately, something critics have argued
would have
saved some or all of the 229 people who died in the crash.
The pilots spent valuable minutes trying to identify the source
of the fire
after smelling smoke 53 minutes into the flight. They diverted
away from the
Halifax airport to dump fuel over the ocean after having a near
full load
since leaving New York for the transatlantic trip.
The board did a theoretical "descent profile" and found the
pilots would
"not have been able to complete a safe landing in Halifax, even
if they had
undertaken to do so at the time of the PAN PAN urgency radio
communication,"
the report says.
The agency, which has spent $60 million and 4½ years examining
millions of
pieces of wreckage in the case, issued nine new recommendations.
Two address
testing and flammability standards of thermal acoustic insulation
materials.
It also recommended improved certification standards for planes'
add-on
systems, such as the entertainment system.
Four recommendations propose improvements to how information from
the flight
data and cockpit voice recorders is captured and stored.
Some aviation experts believe the entertainment unit is key to
the fire.
Critics have said the system was so hastily installed on the
MD-11 that the
proper inspections weren't done to ensure it could operate safely
in the air.
One avionics expert called it a "power-hungry monster" that
demanded an
excessive amount of energy. Critics have blamed the U.S. Federal
Aviation
Administration in part for allegedly shirking its duties in
certifying the
system - something they said the safety board should have
addressed in its report.
The system, which allowed passengers to gamble, play video games
and watch
movies, was found on test flights to raise cabin temperatures and
cause hard
drives in the seats to fail.
The board has released several recommendations and advisories
over the
course of the investigation. They have included calls for more
stringent
testing of electrical wiring in aircraft, inspection of cockpit
wiring of
all MD-11s and independent power sources for flight recorders.
In 1999, after investigators determined that metallized Mylar
insulation on
the plane helped to spread the fire, the FAA ordered
U.S.-registered
airplanes to replace the material within four years.
"It is important to emphasize here that without the presence of
this and
other flammable material, this accident would not have happened,"
Gerden said.
