Complex sentence: The NTSB concluded its investigation on May 4,2010, and determined the probable cause to be "the ingestion of large birds into each engine, which resulted in an almost total loss of thrust in both engines".
Split into simpler sentences: The NTSB concluded its investigation on May 4,2010. It determined the probable cause of the accident to be "the ingestion of large birds into each engine, which resulted in an almost total loss of thrust in both engines".