Primary finding
Probable cause
The failure of the engine ignition system capacitor discharge unit which caused loss of total engine power.
Investigator assessment
Analysis narrative
The pilot was on a flight to test the operation efficiency of the propeller which he planned to replace. He intended to remain in the traffic pattern for the flight. The pilot stated the flight from takeoff through positioning for final leg was without incident. According to the pilot, 'on final approach the engine suddenly sputtered to a stop. Upon noticing th faltering (engine) i immediately gave it full choke and pulled back the throttle back the throttle in order to enrich the fuel flow. I did this in case i had a fuel problem. This procedure had no effect, the engine coasted to a complete stop. I then put the throttle in a start position and closed the choke to initiate a normal warm engine start. I pressed the electric starter button. The engine turned over but gave no indication of starting.' the pilot was unable to glide the distance to the airport and the airplane struck the roof of house. Post accident examination of the engine revealed the capacitor discharge unit of the ignition system had failed.
Source record
Factual narrative
On August 9, 1994, about 1830 eastern daylight time, a Clipped Wings Special II homebuilt experimental airplane, N4287R, lost total engine power on approach to runway 23 at the Suburban Airport located in Laurel, Maryland. During the emergency descent, the airplane collided into a house. The pilot was seriously injured. The house occupants were not injured. The airplane was substantially damaged. Visual meteorological conditions prevailed. The local personal flight was conducted under 14 CFR Part 91. According to the pilot, on final approach to the runway, the engine "...suddenly sputtered to a stop." He stated he tried to restart the engine to no avail. The pilot stated, "At this point I then concentrated more completely on stretching the glide slope in order to avoid hitting any occupied area and perhaps reaching the runway. My efforts succeeded in getting to a point past every occupied dwelling and area below, save the last house between me and a stretch of trees separating it from the airport. My last memory is just above the house." According to a Federal Aviation Administration Safety Inspector, witnesses stated that they heard the engine sputter and then stop. They stated they heard the engine restart and then stop again. They said they looked up to see the airplane and observed it descend straight down into the house. Post accident examination of the engine revealed its Capacitor Discharge Unit had failed. No other engine or airframe anomalies were noted. -