Adult Birds Often Exceed Engine Ingestion Weight Standard

The National Transportation Safety Board confirmed Thursday 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 Thursday. 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, though 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.

(Goose photo by Chuck Szmurlo)

FMI: www.ntsb.gov, www.usairways.com