On January 13, 2006, about 1340 Pacific standard time, a Piper PA-28-181, N35681, registered to and operated by the pilot as a 14 CFR Part 91 personal flight, experienced a loss of engine power followed by a forced landing to a creek bed located about three miles east northeast of Brookings, Oregon. Instrument meteorological conditions prevailed at the time and an instrument flight rules flight plan was filed. The aircraft was substantially damaged and the commercial pilot and his passenger were not injured. The flight originated from Seattle, Washington, four hours and 25 minutes prior to the accident. During a telephone interview and in a subsequent written statement attached to the NTSB Pilot/Operator Report, Form 6120.1/2, it was reported that the pilot received a DUATS online weather briefing the night before the intended flight from Seattle to Torrance, California. Headwinds were forecast for the route, however, the pilot did not consider them "excessive." The pilot reported "Using five hours as the absolute maximum for fuel endurance..." The pilot further reported that he had originally anticipated that on the first leg of the flight he would be able to reach San Jose, California, however, based on the "90% probability trip winds & flight time information" obtained from www.fltplan.com, the pilot decided to make Redding, California, his first stop with an estimated time for this leg of the flight to be four hours and 30 minutes. The pilot's statement indicated that with his experience in flying this aircraft, the "by-the-book" (Pilot Operating Handbook) time for fuel endurance at 75% power is no less than 5:15. For cruise at 65%, what the pilot normally uses, and with a 45 minute reserve, the manual states no less than 5:15, plus the reserve for 6:00. On the day of the accident, the pilot received an updated weather briefing via DUATS and filed a flight plan for Redding, with an intended time en route of four hours and 30 minutes. The pilot verified that the fuel tanks were full and a departure was made at 0915. Near the Battle Ground VOR, the pilot noted higher than expected headwinds, and considered the possibility of diverting to a closer airport. The pilot continued towards Eugene, Oregon, and stayed at 4,000 feet along the route. The pilot reported that nearing the Eugene area, the ground speed did not improve and he "elected to turn farther east on V452 towards LMT (Klamath Falls, Oregon), hoping that a climb (to maintain the 11,000 foot MEA) and a turn in an easterly direction would produce a 10-15 knot increase." The pilot indicated that the diversion had little to no effect on the estimated time to Redding. At this point, the pilot elected to change his destination to Crescent City, California. Air traffic control cleared the aircraft to Crescent City and to descend to 6,000 feet. At the Roseburg, Oregon, area, air traffic control provided the pilot with vectors direct to the Crescent City VOR and to climb to 8,000 feet. The pilot reported that total flight time was approaching 4 hours just before the Roseburg VOR. The pilot reported variable headwinds and a time en route to Crescent City anywhere from 45 minutes to an hour remaining. The pilot reported that he was still expecting fuel endurance to be 5:15 as specified in the aircraft operating handbook. About 30 miles from the Crescent City VOR, at 8,000 feet, the pilot noted a nominal drop in engine rpm. The pilot engaged carburetor heat and requested the lowest altitude that could be maintained to Crescent City. Air traffic control assigned 7,000 feet, however, the engine rpm continued to drop to about 500 and the pilot informed air traffic control of his situation. The pilot realized the emergency situation and he advised air traffic control that he was turning direct to Brookings, Oregon. Air traffic control provided the pilot with terrain obstruction information. The flight descended from 7,000 feet to 2,000 feet in instrument meteorological conditions. The flight broke out of the cloud layer at 2,000 feet. The pilot noted that he would not make the airport at Brookings and opted to make an off airport landing in a clear area. During the descent to a creek bed, the aircraft collided with trees and eventually came to rest in the creek that was swollen from recent rains in the area. The wreckage was recovered from the creek bed on January 21 by personnel from Plain Parts, Pleasant Grove, California. During the recovery, it was noted that the wing fuel tanks were not breached. The recovery personnel drained the fuel tanks and noted that a total of three gallons of fuel was recovered with 17 gallons of water. The wreckage was moved to Pleasant Grove. On March 7, 2006, the owner of Plain Parts prepared the engine for a test run. The spark plugs were pulled and water was drained from the engine. The oil was changed and a fuel supply was added. The owner stated that the engine started with no difficulties. A magneto check was accomplished with a normal drop in rpm noted. All pressures were within normal range. The engine was then shut down with no anomalies noted. The pilot did not provide updated fuel consumption calculations for the unplanned altitude changes along the route of flight which increased from 4,000 feet to 11,000 feet when he opted to divert to Klamath Falls, Oregon, and the 2,000 foot increase in altitude in the Roseburg area. The pilot also did not indicate if he maintained the originally planned 65% cruise power setting which he based his fuel consumption calculations on prior to departing from Seattle. The pilot's operating handbook indicates that total fuel capacity for this make and model aircraft is 50 gallons with 48 gallons useable.