Accident Overview
On an unspecified date, a single-engine airplane encountered failures of its flight and navigation instruments after takeoff and climb in solid instrument meteorological conditions. The pilot, who had accumulated 1,050 flight hours, attempted to maneuver the airplane using partial panel techniques. Radar data indicated that the pilot appeared to be experiencing spatial disorientation. Air traffic control controllers were alerted because the airplane was making left turns instead of the advised right turns.
Witness Observations
Several witnesses observed the airplane flying just below the lowest cloud layer, approximately 125 feet above ground level. One witness located about half a mile from the accident site reported seeing the airplane in straight and level flight at approximately 125 feet agl, slightly below a layer of clouds. Another witness, a private pilot also about half a mile away, heard the engine sound "normal" for about 15 seconds, after which the pitch changed as if the airplane was maneuvering. This witness described the engine as "making good power" but did not see the aircraft due to weather conditions. The airplane then impacted several homes in a residential neighborhood. Both homes and the airplane were destroyed by the post-impact fire.
Weather and Environmental Conditions
The nearest automated surface observing station reported wind from 130 degrees at 6 knots, visibility 7/8 statute miles in mist, and an overcast ceiling at 100 feet. The temperature and dew point were both 17 degrees Celsius, with an altimeter setting of 30.20 inches of mercury.
Aircraft Examination
Due to extensive post-impact fire damage, flight control continuity could not be verified. The instrument panel was completely destroyed by fire. The vacuum pump was separated from its drive, with the drive coupling bent approximately 30 degrees. Disassembly of the vacuum pump showed the rotor vanes were in place and undamaged, but the core element was cracked. The intake and exhaust pipes were separated; the exhaust pipes were separated aft of the mufflers. Examination of the left side ball flange clamp revealed four washers on the bolt; the clamp was tight on the ball flange, and the tailpipe did not move on the ball flange. The exhaust pipes were separated on both sides of the left ball flange. A fire extinguisher from the airplane was found with the handle lock pin missing and the bottle fully discharged.
Investigation Findings
The investigation could not conclude the cause of the pilot's reported loss of instruments during the flight. However, it was noted that the wire bundle connecting the instrument panel through the firewall was in close proximity to the muffler's exhaust flange on the engine side of the firewall.