WPR17FA055 · Mooney M20J

The instrument-rated private pilot/owner regularly used the airplane to commute for work between his home airport and an airport located about 80 miles to the south. On the day of the accident, the pilot departed his home airport and, about 5 minutes after takeoff, established the airplane on a direct course towards an aeronautical navigation beacon that was located on a mountain peak about 28 nautical miles south of the airport, at an elevation of 5,793 ft mean sea level (msl). After takeoff, the airplane initially climbed to about 7,300 ft msl, then descended to about 6,500 ft msl, before ultimately descending to about 5,750 ft msl, where it remained for the last several minutes of the flight.

The pilot was not in radio communication with any air traffic control (ATC) facility during the flight, and had not filed a flight plan, but the airplane had been tracked by ground-based ATC radar. The ATC radar track data ended near the accident site. Both radar and the data from the pilot's onboard GPS device showed that the airplane remained in about straight and level flight for at least 8 minutes before the impact. The wreckage was located about 70 ft below the mountain peak. Ground scars and airplane damage indicated that the airplane was in level flight, with significant engine power, at the time of impact. Examination of the airframe and engine did not reveal any evidence of pre-impact mechanical deficiencies or failures that would have precluded normal operation. Available medical information revealed no evidence of pilot incapacitation.

Meteorological conditions at an airport near the accident location suggested that an overcast ceiling of about 4,750 ft msl was present near the accident site. That ceiling would have obscured the peak, and would have been about 1,000 ft lower than the impact point elevation. It is likely that the pilot flew into instrument meteorological conditions (IMC), which obscured the peak from his view as he attempted to cross the mountain range. The investigation was unable to determine whether the pilot entered IMC intentionally or unintentionally, or how long the airplane was operating in IMC before impact.

The investigation was unable to determine why the pilot was operating on a track at an altitude that did not provide terrain clearance, even if he did intentionally enter IMC without operating under instrument flight rules. Because the ATC radar and GPS altitudes for the flight were congruent, altimetry malfunctions and errors can be eliminated as causal factors. The pilot's GPS unit was capable of providing both visual and aural terrain/obstacle alerts, but the terrain and alert configuration settings of the GPS were not able to be determined. It is possible that the pilot either ignored or deactivated those features, and thereby deprived himself of those protection capabilities. Such a deactivation could have been the result of the pilot's comfort level with flying in that region, or it could have been inadvertent. Although the investigation could not determine what assumptions, tools, or methods the pilot used to ensure adequate terrain clearance for the accident flight, the pilot had sufficient and accurate information available, or potentially available, to enable him to avoid terrain.

All elements of this accident are consistent with a controlled flight into terrain (CFIT) event. Although the specific underlying reasons for the CFIT event could not be determined, it is likely that the pilot's comfort with the route, combined with his determination to complete the flight to reach work, caused him to enter IMC. That entry into IMC, coupled with an improper route and altitude combination, resulted in the collision with the peak.

Verbatim NTSB analysis and probable cause from the NTSB dataset