On January 1, 2005, at 1745 eastern standard time, a Cessna 172L, N7180Q, was substantially damaged during collision with a tree and a fence following a loss of engine power after takeoff from Duchess County Airport (POU), Poughkeepsie, New York. The certificated private pilot was not injured. Visual meteorological conditions prevailed for the local flight that originated, at 1740. No flight plan was filed for the flight conducted under 14 CFR Part 91. The pilot was interviewed by telephone and provided a written statement. He explained that the airplane belonged to a friend, and it was housed in his hangar. The purpose of the flight was to check out the airplane for his friend. The airplane was serviced with fuel about 1 week prior to the accident, and the tanks were filled at that time. After fueling, the pilot "rocked the wings, and held the aircraft tail down" prior to drawing fuel samples. According to the pilot, the samples contained no water. He did not fly the airplane that day due to a scheduling conflict. During the preflight inspection before the accident flight, the pilot again rocked the wings and lowered the tail prior to sampling the fuel. The pilot drew two samples from each wing, and drained "10-12 ounces" of fuel from the gascolator. According to the pilot, the samples contained no water. After the preflight was completed, the airplane was towed outside. The pilot stated that after engine start; he completed the before-takeoff checklist five times, and ran the engine for 18-20 minutes prior to the first takeoff. After takeoff from runway 06, the pilot completed one traffic pattern, performed a touch-and-go landing, and was on climb-out when the engine stopped producing power about 200 feet above ground level. As the pilot maneuvered it back towards the airport, the airplane struck a tree and a fence on the airport perimeter. The airplane came to rest upright, entangled in the fence. On January 3, 2005, a Federal Aviation Administration (FAA) aviation safety inspector examined the airplane. In a telephone interview, he said the gascolator drain valve would not actuate, and would not drain fuel. The gascolator bowl could not be removed due to corrosion, and required two hands to "break it free from its mount." The bowl contained water, with a thin film of fuel on top. The bowl also contained rust and debris, and the gascolator plunger gasket/grommet was torn. The carburetor was drained, and the mixture collected was about 50 percent fuel, and 50 percent water. The carburetor also contained dirt and debris. The contents of the left fuel tank could not be examined due to impact damage and the disposition of the wreckage. Fuel drained from the right tank contained water. The auxiliary tank contained about 4 ounces of fluid. The fluid was drained, and the mixture collected was about 70 percent water. The other 30 percent was an unidentified fluid that was yellow in color. The pilot held a private pilot certificate with a rating for airplane single engine land. He also held a commercial pilot certificate with a rating for rotorcraft helicopter. His most recent FAA second-class medical certificate was issued October 15, 2003. The pilot reported 3,446 hours of flight experience, of which, 1,869 were in single engine airplanes. He reported approximately 50 hours of flight experience in make and model. The tachometer reading at the crash site was 2,083.5 aircraft hours. The most recent annual inspection was completed October 10, 2004, at 2083.2 aircraft hours. At 1753, the weather reported at Duchess County Airport included clear skies with winds from 360 degrees at 8 knots. The temperature was 39 degrees Fahrenheit, and the dewpoint was 27 degrees Fahrenheit. According to the Cessna Pilot Safety and Warning Supplements, rocking the wings, and lowering of the tail, should only be accomplished after contaminants have been discovered in routine fuel sampling. According to the Supplements, "If contamination is observed, take further samples at all fuel drain points until fuel is clear of contaminants; then, gently rock wings and, if possible, lower the tail to move any additional contaminants to the sampling points. Take repeated samples from all fuel drain points until all contamination has been removed." On February 1, 2005, an FAA inspector plumbed a can of aviation gasoline into the airplane's fuel system. The engine started immediately, and ran continuously without interruption. According to the inspector, all instrument readings and the magneto checks were "perfect."