ANC07FA037

A total loss of engine power during takeoff initial climb due to fuel contamination, and the pilot's inadequate preflight inspection.

The private pilot departed from a private airstrip on a personal flight. The airplane climbed to about 200 feet, and then lost power. The pilot made a right turn toward the north, and descended toward a residential area adjacent to the airport. The propeller was not turning just prior to the crash. The airplane clipped the top of a large tree, about 300 feet from a residence, and collided with several additional trees before impacting the ground. The fuel tanks were breached during the accident, but the left inboard tank, when examined at the scene, was nearly full of blue colored fuel. The right inboard tank contained a small amount of fuel. When tested with water detection paste, each tank contained small amounts of water. Fuel was present in the gascolator, and was obtained by opening the forward drain fitting. The aft drain fitting could not be opened due to rust and corrosion. The gascolator also contained sediment, a small amount of water droplets, corrosion around the base of the gascolator screen and the gascolator base, and small globs of a white, opaque, silicone-like grease material. Small globs of the grease material were also found in the carburetor inlet screen, and in the check valve between the gascolator and the carburetor. The interior of the fittings of fuel supply line from the gascolator and the carburetor had some corrosion. The engine was removed from the airframe and placed on an engine test stand. A replacement carburetor was installed, along with a wooden "club" test propeller. The engine was started and produced full rated rpm. The accident carburetor was placed on a test stand and it held normal fuel pressure without leaking. The carburetor bowl contained dirt, sediment, and small amounts of water. The accelerator pump functioned properly. The floats operated normally without binding. The airplane had been flown about 22 hours in the previous 2 years.

HISTORY OF FLIGHT On May 4, 2007, about 1548 Alaska daylight time, a tundra tire-equipped Cessna 170 airplane, N4217V, sustained substantial damage when it collided with trees during a forced landing after takeoff from the Wolf Lake Airport, Wasilla, Alaska. The airplane was being operated as a visual flight rules (VFR) local area personal flight under Title 14, CFR Part 91, when the accident occurred. The airplane was operated by the pilot. The private certificated pilot, the sole occupant, received fatal injuries. Visual meteorological conditions prevailed, and no flight plan was filed. A witness reported that he saw the airplane depart on runway 19 at Wolf Lake. The airplane climbed to about 200 feet, and the witness heard the engine lose power. The pilot made a right turn toward the north, and descended toward a residential area adjacent to the airport. A ground witness reported that the propeller was not turning just prior to the crash. The airplane clipped the top of a large tree, about 300 feet from a residence, and collided with several additional trees before impacting the ground. PERSONNEL INFORMATION The pilot held a private pilot certificate with an airplane single-engine land rating that was issued June 11, 2004. The most recent third-class medical certificate was issued to the pilot on July 1, 2003, and contained no limitations. The pilot began flight training on June 7, 2001, in a Cessna 150. He accrued about 33.2 hours in the Cessna 150 until October 12, 2001. The pilot began logging flight hours in the accident airplane on February 17, 2002. He accrued 105.8 hours in the accident airplane until June 11, 2004, when he received his private pilot certificate. A review of the pilot's logbook revealed that his most recent entry was February 17, 2005. At that time, his flight experience was 159.3 hours. Additional flight time was recorded in a separate logbook, which the pilot used to track flight hours on the airplane. The last entry was dated September 6, 2006. This additional time between February 17, 2005, and the accident date, totaled 37.9 hours. The pilot's total aeronautical experience consisted of 197.2 hours, of which 164.0 were accrued in the accident airplane. AIRCRAFT INFORMATION At the accident scene, the airplane's recording hour meter indicated 1,759.32 hours. Examination of the maintenance records revealed that the most recent annual inspection was accomplished on October 15, 2006. At that time, the airplane had accrued 4,399.4 hours, and the hour meter reading was 1,755.3, which was 4 hours before the accident. The maintenance records noted that a major overhaul was accomplished on February 7, 2003, by a mechanic using new and overhauled parts. At that time the hour meter reading was 1,644.9, which was 114.4 hours before the accident. Between July 17, 2005, and the accident date, the pilot flew about 22.4 hours in the airplane. At the time of the accident, the airframe's total time in service was 4,403.4. The engine had accrued a total time in service of 3,619.3 hours. The airplane's original fuel system consisted of three, 12.5 gallon fuel tanks. Two interconnected tanks were installed in the right wing, with a single tank in the left wing. A fourth 12.5 gallon fuel tank was added to the left wing at an unknown time. The two tanks per wing were interconnected via rubber hoses. The fuel cap, tank drain fitting and vent, were located on the inboard tanks. The outboard tanks did not have a drain fitting. Review of the maintenance records revealed a copy of a supplemental type certificate (STC) SA869NW, issued by the FAA in December, 1979. The STC was for the installation of a right wing 12.5 gallon auxiliary fuel tank in the left wing, but was issued to a Cessna 170 other than the accident airplane. The copy of the STC was accompanied by drawings, and a letter from the holder of the STC, dated January, 1994, which described the fabrication process necessary for the tank installation. The airframe logbook did not contain any record of installation of the auxiliary tank. The logbooks did contain a record of an FAA Form 337 approved airframe alteration, dated January 18, 2002, in which a certificated aviation mechanic stated that the left tank installation was previously installed by persons unknown. Further, the mechanic stated that the installation was inspected and determined to be done in accordance with STC SA869NW. The Form 337 was approved by an FAA inspector with the Fairbanks, Alaska, Flight Standards District Office (FSDO). The employer and friend of the pilot reported that several 5 gallon fuel jugs were located in the pilot's vehicle. METEOROLOGICAL INFORMATION The closest official weather observation station is Wasilla, Alaska, which is located 8 nautical miles south-southwest of the accident site. At 1556, an Aviation Routine Weather Report (METAR) was reporting, in part: Wind, 220 degrees (true) at 6 knots; visibility, 10 statute miles; clouds, 8,500 feet scattered, 10,000 feet scattered; temperature, 51 degrees F; dew point, 32 degrees F; altimeter, 29.85 inHg. COMMUNICATIONS There were no communications received from the pilot. AIRPORT AND GROUND FACILITIES The Wolf Lake Airport is a private airport. It is equipped with a single hard-surfaced runway on a 240 to 060 degree magnetic orientation, and a second gravel-surfaced runway on a 010 to 190 degree magnetic orientation. Runway 19 is 2,600 feet long by 100 feet wide. WRECKAGE AND IMPACT INFORMATION The National Transportation Safety Board (NTSB) investigator-in-charge (IIC), and Federal Aviation Administration (FAA) inspectors, examined the airplane at the scene on May 4, 2007. Following recovery, the NTSB IIC and the parties to the investigation examined the airplane wreckage on May 7, 2007. All of the airplane's major components were found at the main wreckage area. The airplane came to rest at the base of a large birch tree on a magnetic heading of 014 degrees. (All heading/bearings noted in this report are oriented using magnetic north.) About a 6 foot segment of a tree branch was located about 300 feet southeast of the airplane point of rest. Above the airplane point of rest, impact marks and blue paint transfers were noted on tree trunks, about 25 feet above the ground. The right wing had extensive spanwise leading edge aft crushing. Outboard from the lift strut attach point, the right wing was bent aft about 90 degrees. The inboard section of right wing leading edge was crushed aft, with flat, slight upward crushing. The left wing was broken from the fuselage attach points, and displaced downward about 45 degrees, out to the mid-span lift strut attach point. Outboard from that point, the left wing was crushed aft and folded around the base of birch tree, and had extensive folding and destruction. The wing carry-through was broken, with a large aft crush at the left wing attach point where it struck a large birch tree trunk. The lower end of the left wing lift strut was attached to the fuselage, but was crushed aft and bent 90 degrees around the base of the tree. The flight control surfaces remained connected to their respective attach points, and had extensive impact damage. Due to impact damage, the flight controls could not be moved by their respective control mechanisms, but continuity of the flight control cables was established to the cockpit. The fuselage was resting flat on the ground. The tailwheel was broken from its assembly. The empennage was bent to the left at the forward edge of the vertical stabilizer attach point. The outboard end of the left elevator was bent upward, but the empennage was otherwise undamaged. The right main landing gear assembly separated from the fuselage and was just forward of the right door. The left main landing gear assembly was pivoted aft and upward. The nose section of the f