On October 15, 1999, about 1622 Alaska daylight time, a Piper PA-31-T3 airplane, N220CS, sustained substantial damage when it collided with a bird about 18 miles east of Gambell, Alaska, about latitude 63 degrees, 41.5 minutes north, and longitude 171 degrees, 05.0 minutes west. The airplane was being operated as a visual flight rules (VFR) scheduled domestic passenger flight under Title 14, CFR Part 135, when the accident occurred. The airplane was operated as Flight 394 by Cape Smythe Air Service Inc., Nome, Alaska. The airline transport certificated pilot, and the four passengers, were not injured. Visual meteorological conditions prevailed. A VFR flight plan was filed. The flight originated at the Savoonga Airport, Savoonga, Alaska, about 1615. A Federal Aviation Administration (FAA) airworthiness inspector, Fairbanks Flight Standards District Office (FSDO), reported he was notified by the operator of the bird strike. The flight was a continuation of a scheduled flight from Nome, to Gambell, located on Saint Lawrence Island, in the Bering Sea. The FAA inspector said that the pilot reported he was in cruise flight at 2,500 feet msl, at an airspeed of about 200 knots. He said he caught a glimpse of a sea gull that suddenly dove toward the water. The sea gull struck the right wing, outboard of the right engine nacelle. The pilot landed at Gambell without any problems. The Director of Maintenance for the operator reported the upper surface of the leading edge received downward, and aft crushing of the wing structure about 18 inches across, and about 8 inches deep. The damage to the wing included several ribs, forward spar, leading edge skin, and the deice boot.