On October 6, 1999, about 2230 Eastern Daylight Time, a Bombardier de Havilland DHC-8-102, N818EX, sustained substantial damage while in cruise flight, approximately 5 miles north of Philadelphia, Pennsylvania. The airplane was owned by Seventh Leasing Corporation, and operated by Allegheny Airlines Inc. The 3 crewmembers and 12 passengers were not injured. Visual meteorological conditions prevailed for the flight that originated from Philadelphia International Airport (PHL), Philadelphia, Pennsylvania; destined for Lehigh Valley International Airport (ABE), Allentown Pennsylvania. An instrument flight rules flight plan was filed for the passenger flight conducted under 14 CFR part 121. According to the Captain's written statement: "Multiple large bird strikes at 3000' MSL about 5 NM North of PHL. Had departed PHL for ABE, and leveled of(f) at cruise. While we suspected multiple strikes, only one impact sound was heard as apparently all birds hit at the same time. Extensive damage was not suspected, so flight continued to ABE..." The airplane was examined by a Federal Aviation Administration Inspector. The Inspector observed an approximate 12-inch hole in the front spar of the left wing. He also noted damage to the propellers and radome.