NYC03FA129 · Cessna 150H

The flight instructor and a certificated pilot were conducting a local instructional flight. According to a witness, he heard the aircraft power up and start its take off roll. He then heard the engine "skip," which made him look up and observe the airplane in a steep left turn with a nose high attitude. At the same time he heard the engine noise decrease "like the throttle was pulled to idle." When the airplane was about parallel with the "old runway 28," the witness observed the tail swing aggressively to the right, and at the same time, he heard the engine rev-up. The airplane then stalled, and began to spiral downward counter-clockwise, before impacting the asphalt and bursting into flames. Several other witnesses had observed the airplane flying 30 minutes prior to the accident. The local training flight was the airplane's first flight since the annual inspection was performed 2 months prior to the accident. Inspection of the carburetor revealed contaminated residual fuel and contamination of the fuel screen. Examination of the fuel sample and the fuel screen revealed that the fuel sample contained water, copper sediments, and varnish. The fuel sample was consistent with "old fuel." Residue observed on the fuel screen was consistent with grease. Review of maintenance records revealed that the airplane's most recent annual inspection was performed on April 1, 2003. The work accomplished during the annual inspection included the draining of the fuel sumps, and inspection of the fuel screen. The maintenance records also contained a checklist for a 100 hour inspection, dated March 31, 2003, and a discrepancy sheet log. Included in the checklist was, "Drain carburetor float bowl - resafety plug... Remove fuel inlet screen from carb or injection throttle body, clean, reinstall and safety." The checklist items were initialed by a mechanic, and additionally by an inspector. Included in the discrepancy sheet log was an entry which stated, "carb float bowl drain froze in place, fab tool to remove and removed drain plug." The entry was initialed by a mechanic. According to 14 CFR Part 43 Appendix D - Scope and Detail of Items (as Applicable to the Particular Aircraft) To Be Included in Annual and 100 Hour Inspections, "Each person performing an annual or 100 hour inspection shall inspect (where applicable) components of the engine and nacelle group..."

Verbatim NTSB analysis and probable cause from the NTSB dataset