WASHINGTON (Reuters) - U.S. safety investigators
have for years pressed regulators to take stronger and swifter
action to mitigate the dangerous effects of aircraft icing, a
stand prompted by crashes more than 15 years ago.
Icing quickly emerged as a leading possible cause for why a
Continental Connection turboprop fell out of the sky in
wintry conditions and plunged into a house near Buffalo, New
York, late Thursday, killing all 49 people on the plane and
one person on the ground.
While the National Transportation Safety Board
investigation of commuter Flight 3047 will take several months
at least, records showed the board has been dissatisfied with
the Federal Aviation Administration's response to four of its
icing-related safety recommendations, one dating to 1996.
The safety board issued a safety alert last December based
on one of the two outstanding icing-related recommendations
that it made to the FAA in 2007.
That one would require crews to activate anti-icing systems
or rubber "boots" designed to break up accumulated ice on the
leading edge, or front, of the wings once a plane enters icy
conditions, unless there is a specific instruction from the
manufacturer not to do so.
Safety board investigators in Buffalo said Friday that
"black box" recordings showed the crew of Flight 3407 commented
on ice buildup on the windshield and the leading edge of the
wings of the year-old Dash 8 Q400 shortly before the crash.
It was not clear what procedures were in place for the crew
at Colgan Air, which was operating the flight. Colgan is a unit
of Pinnacle Airlines.
TURBOPROPS MORE VULNERABLE
Officials at Pinnacle and aircraft manufacturer Bombardier
Inc could not be reached for comment late Friday.
The Dash 8 Q400 has had a good safety record, officials said.
Colgan Dash 8s carried 941,000 passengers on 19,000 flights
during the first 11 months of 2008, federal records show.
Even a light coating of ice no rougher than sandpaper can
cut the amount of lift generated by the wings and increase the
minimum speed at which the wing ceases to produce lift, a
condition known as stall.
Three major icing-related accidents -- including one in
Indiana that killed 68 people in 1994 and another about two
years later in Detroit that killed 29 -- focused attention on
icing and turboprops.
Turboprops are more vulnerable to icing than jets because
they spend more time at lower altitudes where icing is likely
FAA safety orders, aircraft modifications and changes to
pilot training resulted from inquiries into the crashes, but
the safety board believes regulators are moving too slowly on
its call for stricter action.
Currently, the FAA has three rules in the pipeline to
address the NTSB icing recommendations. But there is no
timetable for finalizing them and no assurance that the safety
board will be satisfied.
Laura Brown, an FAA spokeswoman, said one proposal would
allow pilots to more quickly detect icing and address it. "It
would help prevent accidents where pilots don't know it's
building up," she said.
(Additional reporting by Tim Dobbyn; Editing by Xavier