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NTSB ADVISORY
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National Transportation Safety Board
Washington, DC 20594
February 12, 2009
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FOURTH UPDATE ON INVESTIGATION INTO DITCHING OF US AIRWAYS
JETLINER INTO HUDSON RIVER
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The following is an update on the National Transportation
Safety Board's investigation of US Airways flight 1549,
which ditched into the Hudson River on January 15, 2009.
The bird remains found in both engines of US Airways flight
1549 have been identified by the Smithsonian Institution's
Feather Identification Laboratory as Canada Goose (Branta
canadensis).
The lab made the identification for the NTSB through DNA
analysis as well as through morphological comparisons in
which feather fragments were compared with Canada Goose
specimens in the museum's collections; the microscopic
feather samples were compared with reference microslide
collections.
A total of 25 samples of bird remains have been examined as
of today. Additional analysis will be conducted on samples
received from the NTSB to attempt to determine if the Canada
Geese were resident or migratory. While no determination has
been made about how many birds the aircraft struck or how
many were ingested into the engines, an adult Canada Goose
typically ranges in size from 5.8 to 10.7 pounds, however
larger individual resident birds can exceed published
records.
The accident aircraft was powered by two CFM56-5B/P turbofan
engines. The bird ingestion standard in effect when this
engine type was certified in 1996 included the requirement
that the engine must withstand the ingestion of a four-pound
bird without catching fire, without releasing hazardous
fragments through the engine case, without generating loads
high enough to potentially compromise aircraft structural
components, or without losing the capability of being shut
down. The certification standard does not require that the
engine be able to continue to generate thrust after
ingesting a bird four pounds or larger.
NTSB investigators worked closely with wildlife biologists
from the United States Department of Agriculture, both at
the scene of the accident in New York City and during the
engine teardowns at the manufacturer's facility in
Cincinnati, to extract all of the organic material that was
identified today.
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