Accident Overview
On March 28, 2009, at approximately 1050 Pacific daylight time, a Piper PA-28-235, registration N9249W, impacted terrain during an attempted forced landing about one-half mile east of the departure end of Runway 12 at San Carlos Airport, San Carlos, California. The private pilot and his three passengers received serious injuries, and the airplane, owned by Flying Veterans Club of San Francisco, sustained substantial damage. The flight was a Title 14 Code of Federal Regulations Part 91 Young Eagles introductory flight that had departed San Carlos Airport less than one minute prior to the accident. Visual meteorological conditions prevailed, and no flight plan had been filed.
Pilot Actions and Engine Failure
According to the pilot, after arriving at the airport around 0915, he completed a pre-flight inspection including fuel quantity, type, and quality checks. He started the engine, performed an engine run-up (including cycling the propeller), then taxied to Hiller Aviation to pick up his Young Eagle passengers. He shut down, completed paperwork, and loaded three passengers after calculating weight and balance. He started the engine, checked gauges, obtained ATIS, and taxied to Runway 12 with a taxi clearance.
At the runway, after receiving takeoff clearance, he added full power. The engine accelerated normally and appeared to run strong. He began the takeoff sequence, including a normal noise-abatement 30-degree left turn after establishing climb. As the airplane reached between 100 and 150 feet above ground level (AGL), the engine suddenly lost all power.
The pilot ensured the throttle was full forward, fuel selector set to the right main tank, and fuel boost pump on. Unable to determine the cause of the power loss at low altitude, he focused on selecting a safe landing area in the marshy terrain nearby.
Forced Landing and Damage
About 10 to 15 seconds after power loss, the pilot touched down on rough marsh terrain. The airplane came to a stop with the nose protruding over the edge of an open canal in Steinberger Slough. The landing sequence resulted in substantial damage to both wings and the lower forward portion of the fuselage.
Post-Accident Examination
After the accident, it was determined that both wing fuel tanks were near full. The airplane was removed and taken to Plane Parts Enterprises in Pleasant Grove, California, for inspection and disassembly. Investigators examined the fuel system, engine air induction system, engine ignition system, propeller governor, engine controls, and engine mechanical drive train.
The crankshaft rotated freely in both directions when turning the propeller by hand, and thumb compression was observed in proper order in all six cylinders. Mechanical continuity from the crankshaft to the accessory section and rocker boxes was confirmed. The valve train operated freely with normal lift at each rocker assembly. Top spark plugs showed no abnormal wear or pre-impact contamination. Cylinder combustion chambers were mechanically undamaged with no evidence of detonation. Cylinder and exhaust system coloration was normal except for salt water corrosion.
The right magneto produced spark at all six plug leads during hand rotation and was securely clamped and timed to number one cylinder at 25 degrees before top dead center (BTDC). The left magneto did not produce spark due to contamination and corrosion from salt water intrusion, but it was also securely clamped and timed to 25 degrees BTDC. The carburetor bowl was filled with water, yet disassembly found no mechanical anomalies; throttle and mixture controls were securely attached. A few drops of water were found in the gasculator, but uncontaminated fuel (no water detected) was present in the fuel line from the firewall to the engine-driven fuel pump. The engine-driven fuel pump was free of internal malfunction and its diaphragm was intact. The electrical fuel pump produced pressure in the green arc. The air induction system was unobstructed with a securely attached filter.
At the conclusion of the inspection, no evidence of pre-impact malfunctions, anomalies, or contamination in any of the aforementioned systems was found.