Aviation Accident Summaries

Aviation Accident Summary WPR09LA169

San Carlos, CA, USA

Aircraft #1

N9249W

PIPER PA-28-235

Analysis

The pilot had just departed on a local visual flight rules (VFR) flight when the airplane's engine suddenly lost all power as it was about 100 to 150 feet above ground level. Because of the airplane's low altitude, once the pilot checked the position of the magnetos, fuel selector, and fuel pump, he focused his attention on finding a landing spot in the nearby rough swampy terrain. During the landing, the airplane's wings and fuselage sustained substantial damage. A post-accident teardown inspection of the airframe, fuel system, air induction system, and the engine did not find any evidence of pre-accident anomalies or malfunctions.

Factual Information

On March 28, 2009, about 1050 Pacific daylight time, a Piper PA-28-235, N9249W, impacted the 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 were reported to have received serious injuries, and the airplane, which was owned by Flying Veterans Club of San Francisco, sustained substantial damage. The Title 14 Code of Federal Regulations Part 91 Young Eagles introductory flight, which took off from San Carlos Airport less than one minute before the accident, was being operated in visual meteorological conditions. No flight plan had been filed. According to the pilot, after arriving at the airport about 0915, he completed a pre-flight inspection of the airplane. That inspection included, among other actions, a check of the fuel quantity, type, and quality (including lack of contamination). After completing his pre-flight inspection, the pilot started the engine, and then performed an engine run-up check, to include cycling the propeller. He then taxied to Hiller Aviation, where he would be picking up his Young Eagle passengers. Once at Hiller Aviation, the pilot shut down the airplane, went inside to complete the required paperwork, and then was assigned the three passengers that he would be taking up. After calculating his weight and balance figures based upon the assigned passengers, the pilot loaded the passengers into the airplane. He then started the engine, checked his engine gauge readings, obtained the Automatic Terminal Information Service (ATIS), and taxied to Runway 12 after receiving a taxi clearance. After arriving at the approach end of the runway and waiting for landing traffic, the pilot was cleared onto the runway for takeoff. At that time he added full power, and according to the pilot, the engine accelerated as expected, and appeared to be running strong and "normal." He then continued the takeoff sequence, to include the beginning of the normal noise abatement 30 degree left turn after establishing his climb. Then, as the airplane reached an altitude between 100 to 150 feet above ground level (AGL), its engine suddenly lost all power. The pilot then made sure that the throttle was full-forward, that the fuel selector was set to the right main tank, and that the fuel boost pump was on. At that point, because he could not determine what the reason for the power loss was, and because he was at a low altitude, the pilot switched his focus to selecting a safe landing area in the marshy terrain nearby. According to the pilot, about 10 to 15 seconds after the airplane lost power, he touched down on the very rough terrain of the marsh, and came to a stop with the nose of the airplane protruding over the edge of an open canal in Steinberger Slough. The forces attenuated during the landing sequence resulted in substantial damage to both wings and to the lower forward portion of the fuselage. After determining that the fuel tanks in both wings were near the full level, the airplane was removed from the marsh and taken to the facilities of Plane Parts Enterprises, in Pleasant Grove, California, for further inspection and disassembly. During that inspection, the airplane's fuel system, engine air induction system, engine ignition system, propeller governor, engine controls, and engine mechanical drive train were examined The crankshaft was able to be freely turned in either direction while pulling the propeller by hand, and "thumb" compression was observed in the proper order in all six cylinders. Mechanical continuity was established from the crankshaft to the accessory section and the rocker boxes. The complete valve train operated freely and in proper order, with "normal" lift action being observed at each rocker assembly. The top spark plugs were removed and inspected, and showed no abnormal wear or evidence of pre-impact contamination or damage. The cylinder combustion chambers were mechanically undamaged, and there was no evidence of detonation. The cylinder combustion chambers and the exhaust system displayed coloration consistent with normal operation, except for varying degrees of corrosion from salt water intrusion. The right magneto produced spark at all six plug leads during hand rotation, and it was found to be securely clamped to its mounting pad and timed to the number one cylinder at 25 degrees before top dead center (BTDC). The left magneto would not produce spark due to contamination and corrosion from salt water intrusion, but it was securely clamped to its mounting pad, and timed to the number one cylinder at 25 degrees BTDC. Although the bowl of the undamaged carburetor was filled with water, a disassembly inspection did not find any mechanical anomalies, and both the throttle and mixture controls were securely attached at their respective control arms on the carburetor body. Although there were a few drops of water found in the gasculator, uncontaminated fuel was found in the fuel line from the firewall to the engine-driven fuel pump, and no water was detected in that fuel using "Kolor-Kut' water detection paste. The engine driven fuel pump was removed for examination, and was found to be free of internal mechanical malfunction or obstruction to flow. Its diaphragm remained intact. The electrical fuel pump was tested and was able to produce fuel pressure in the green arc of the fuel pressure gauge. The air induction system was free of obstruction, and its filter was securely attached and appeared free of any pre-impact obstruction. At the end of the inspection process no evidence of pre-impact malfunctions, anomalies, or contamination associated with any of the aforementioned systems had been found.

Probable Cause and Findings

A total loss of engine power during the initial climb for undetermined reasons.

 

Source: NTSB Aviation Accident Database

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