Beaver, OR, USA
N9240W
Woodley Zodiac 601HD
The pilot reported that while in cruise flight, the engine sounded different like it dropped a few rpm's. The pilot applied carburetor heat which didn't help. The pilot then checked one side of the dual ignition system and found that one side was inoperative. The engine continued to run for a few more minutes, then quit. The pilot tried to restart the engine by cranking the starter, applying boost pump, primer and the emergency 12-volt ignition system. The engine would not start and the pilot set-up for a landing on a highway. During the landing roll, the airplane collided with an embankment. During the post-accident engine run and inspection, it was noted that the engine had been modified since it left the manufacturer. Further inspection of the engine identified that ignition A (right side) revealed an open circuit with a defective sensor. It was also found that the alternate 12 VDC source switch in the on position shorted the master. The engine would not start if the alternate 12-VDC switch was in the on position.
On April 18, 2002, approximately 1415 Pacific daylight time, an experimental Zodiac 601HD, N9240W, registered to and operated by the pilot as a 14 CFR Part 91 personal flight, experienced a loss of engine power. The pilot initiated a forced landing to Highway 101, about two miles south of Beaver, Oregon. During the landing roll, the aircraft collided with an embankment. Visual meteorological conditions prevailed at the time and no flight plan was filed. The aircraft was substantially damaged and the commercial pilot, the sole occupant, was not injured. The flight departed from Independence, Oregon, about 35 minutes prior to the accident. During a telephone interview and subsequent written statement, the pilot reported that he had just purchased this aircraft and it was his first flight. While en route to Tillamook, Oregon, about 4,500 feet, the "engine sounded a little different like it had dropped a few RPMs and I applied carb heat but that didn't help." The pilot then checked one side of the dual ignition system and found that one side was inoperative. The engine continued to run for a few minutes longer, then quit. The pilot attempted to restart the engine by cranking the starter and applying boost pump, primer and the emergency 12-volt ignition system. The engine would not restart and the pilot set-up for a landing. As there was no traffic in view, the pilot opted to land on Highway 101. During the landing roll, the airplane collided with an embankment. The initial engine inspection was accomplished in the presence of the Federal Aviation Administration Inspector from the Hillsboro, Oregon, Flight Standards District Office. The inspector reported that the fuel in the fuel tank was clean and free of water. The engine was visually inspected with no obvious anomalies noted. The engine was then prepared for starting. The inspector reported that it was hard to start, but after it started, it ran smoothly. The ignition switch was then turned to the "Left Mag" position, and the engine immediately shut off. (See attached FAA Engine Inspection report) The wreckage was then transported to Arlington, Washington, the pilot's home base and the location of the engine manufacture. A representative of the manufacture, NSI Propulsion Systems, in the presence of the National Transportation Safety Board, Investigator-In-Charge, further inspected the engine. (see attached NTSB Engine Inspection report). During the inspection, it was noted that several modifications had been made to the engine. With the known results of the previous engine inspection, the A and B ignition system was tested for resistance. The manufacture reported that the resistance should be 625 ohms, +/- 25 ohms. Ignition A (right side) revealed an open circuit with a defective sensor. Ignition B (left side) displayed 603 ohms. The engine was then started. During the troubleshooting process, the engine shut down when the switch was turned to the "Left Mag" verifying the sensor failure. Further inspection found that there was a short circuit to the master which was drawing high current. The Alternate 12 VDC source switch in the on (up) positioned shorted the master. In the on position, it drained the master circuit down to 8 volts. The manufacture reported that the ignition will stop working around 9 volts. The engine would not start if the switch was in the on position. The manufacture reported that a sensor failure in the right side ignition system would probably create an intermittent miss, which the pilot initially reported, however, the engine would continue to run. The Subaru EA-81 engine is equipped with a dual breakerless electronic ignition. The ignition includes a steel toothed trigger wheel that is bolted to the crankshaft, two magnetic proximity sensors, two coils and a single or twin pack electronic control modules. There is one spark plug per cylinder. The manufacturer refers to the system as Ignition A and B. The ignition switch in the aircraft identified the system as left and right mag (magneto). Maintenance records indicate that on September 3, 1998, the aircraft had accumulated a total flight time of 72.6 hours. At this time the aircraft was signed off in an airworthy condition. On August 15, 2001, the aircraft had accumulated 74.8 hours and again was signed off in an airworthy condition. There were no other logbook entries for this aircraft up to the time of the accident. At the time of the accident, the aircraft had accumulated a total time of 79.7 hours.
A partial failure of the electrical (ignition) system and a short to the master electrical switch during cruise flight resulting in a loss of engine power. A collision with an embankment during the landing roll was a factor.
Source: NTSB Aviation Accident Database
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