ERA17FA231 · Cessna 152

The noninstrument-rated private pilot departed on a night flight for which he had not received proper authorization from the flight school that owned the airplane. For most of the approximate 30-minute flight, including taxi and takeoff, the pilot was conducting a video call with his girlfriend, but ended the call about 6 minutes before the accident occurred. During the flight, the pilot completed one practice hold pattern, maintaining nearly constant altitude about 1,400 ft mean sea level, then turned right toward an area with no ground reference lights, likely to perform another hold pattern, during which the airplane's altitude began to vary. The airplane then entered a right descending turn, during which it exceeded the standard turn rate, reached a rate of descent about 6,000 ft per minute, and subsequently impacted the ground. The airplane was destroyed by high-energy impact forces.

Personnel from the flight school assumed that the airplane had become stuck at a coastal airport due to weather but did not attempt to locate the pilot and did not report the airplane missing until 4 days later. An undetermined malfunction of the airplane's emergency locator transmitter (ELT) likely also contributed to the delay in identifying the crash and locating the wreckage. The wreckage was subsequently located, recovered, and examined; there were no discrepancies with the airframe, flight controls, engine, or recovered engine accessories.

The flight instructor who flew in the airplane earlier the day of the accident with the accident pilot later reported that the attitude indicator displayed a "3° or less" right bank during that flight; he did not write up the discrepancy. However, the airplane's directional gyro and attitude indicator displayed a heading and bank angle consistent with the radar data and the disposition of the wreckage path, which suggests an operative vacuum system and functional vacuum-operated flight instruments at the time of the accident. Although debris was found in the vacuum regulating valve, the debris was consistent with material produced by an insect, which likely entered the valve after the accident occurred.

Postaccident toxicology testing of specimens from the pilot identified ethanol and n-propanol. It is likely that the n-propanol and some of the ethanol was from postmortem production; however, the investigation was unable to eliminate the possibility that some of the ethanol could have been from ingestion and could not determine whether or to what extent it may have contributed to the accident.

Conditions conducive to the development of spatial disorientation were present at the time of the accident, including the night conditions, operating over an area with no ground lighting, scattered clouds (which would have reduced available moon illumination). Additionally, the airplane's spiraling descent and the fragmentation of the wreckage due to high-energy impact are consistent with the known effects of a loss of control due to spatial disorientation.

Verbatim NTSB analysis and probable cause from the NTSB dataset