CEN17FA258 · Piper PA 28-181

The private pilot and the passenger were making an instrument flight rules personal cross-country flight in the airplane. Radar data showed that the airplane was in cruise flight about 7,000 ft mean sea level (msl) until the pilot began a descent toward the initial approach fix for the GPS approach to the destination airport. Cloud tops in the area were about 6,200 to 6,900 ft msl; thus, the airplane likely entered clouds (instrument meteorological conditions) as it descended. The final 2.5 minutes of the radar data revealed erratic turns left and right, which were consistent with the pilot becoming spatially disorientated while descending in instrument meteorological conditions. The last radar point recorded the airplane about 2,950 ft msl or about 2,100 ft above ground level (agl); the reported cloud base at the destination airport was 1,200 ft agl. A witness reported that low overcast clouds were present as he heard the airplane fly overhead. The witness saw the airplane exit the clouds in a steep angle of descent with the engine operating at high power. The airplane disappeared behind a tree line and a few seconds later impacted a reservoir. The deviation from the intended flight path, erratic maneuvering, and steep descent in instrument meteorological conditions are consistent with spatial disorientation. A postaccident examination of the airplane and engine did not reveal any mechanical malfunctions or failures that would have precluded normal operation. The engine and propeller exhibited signatures consistent with high engine power at impact. The vacuum pump remained intact and did not exhibit any preimpact anomalies.

Although the pilot held an instrument rating, his total instrument flight experience could not be determined. The pilot's autopsy revealed severe coronary artery disease that put him at risk of an acute coronary event; however, it is unlikely that symptoms of shortness of breath, chest pain, palpitations, or fainting would lead to the type of airplane performance findings present in this case. Therefore, it is unlikely the pilot's heart disease contributed to the accident. Although the coroner's toxicology testing identified ethanol, the fact that it was absent on two other tests of liver and brain tissue indicates it was from sources other than ingestion and did not contribute to the accident. There is no evidence of a medical condition or substance that contributed to this accident.

Verbatim NTSB analysis and probable cause from the NTSB dataset