On August 11, 1998, about 2020 Alaska daylight time, a wheel equipped Piper PA-31-350 airplane, N3527U, sustained substantial damage during an unintentional gear-up landing at the Fort Yukon Airport, Fort Yukon, Alaska. The airplane was being operated as a visual flight rules (VFR) on-demand passenger flight under Title 14, CFR Part 135, when the accident occurred. The airplane is registered to, and operated by, Warbelow's Air Ventures, Inc., Fairbanks, Alaska. The certificated airline transport pilot, and the seven passengers aboard were not injured. Visual meteorological conditions prevailed, and VFR company flight following procedures were in effect. The flight originated at the Fairbanks International Airport, Fairbanks, about 1910. During a telephone conversation with the National Transportation Safety Board investigator-in-charge on August 11, the pilot reported that while on downwind for landing on runway 21, a passenger in the rear of the airplane distracted his attention while he was performing his prelanding checks, and he failed to lower the landing gear prior to landing. The pilot stated that: " I just forgot to put the gear down after talking to the passenger." In his written statement to the National Transportation Safety Board (NTSB), the pilot added that while on short final, a flock of large birds again distracted his attention from completing the "final gear check before landing." He said that the airplane landed on its belly, slid for about 550 feet, and came to rest in the center of the runway, about 1,000 feet from the threshold of the approach end of runway 21. The airplane sustained substantial damage to the fuselage bulkheads, and belly skin. The pilot noted that there were no preaccident mechanical anomalies with the airplane.