WPR20FA031 · Grumman AA5 B

The noninstrument-rated pilot and passenger were departing on a cross-country flight in dark night visual meteorological conditions. A witness and onboard data indicated that the airplane lifted off the runway about midfield, initiated a left turn near the departure end of the runway, and impacted the ground seconds later. The accident site, which comprised a long debris field, suggested a high-velocity impact. Examination of the wreckage did not reveal evidence of any preimpact mechanical anomalies. The elevator trim was discovered in the full nose-down position, which would have resulted in the pilot experiencing significant resistance to his control inputs during a takeoff and climb. It is possible that the trim position having been misconfigured to before the takeoff could have served as a distraction that led to the development of spatial disorientation. It is also possible that the airplane’s pitch attitude led to the pilot manually adding nose down trim. Thus, there was insufficient evidence to determine the role of the nose-down trim in the sequence of events. Although the pilot’s logbooks were not recovered during the investigation, discussions with friends and family members suggested that he did not normally fly at night and had experienced only a few nighttime departures at the accident airport before the accident. GPS data from previous flights revealed that the pilot departed the same runway at night on two occasions before the accident; however, the moon was prominently illuminated during both of the previous flights. The area of the accident airport was sparsely populated, with little to no cultural lighting present in the direction of the accident takeoff. On the night of the accident, the pilot’s visual references were limited, as the moon was not visible above the horizon. The pilot entered a climbing left turn as customary shortly after takeoff, likely to avoid an obstacle beyond the runway. The moonlight on previous takeoffs would have reduced his reliance on runway lighting. Given the lack of visual references and the pilot’s lack of experience in night operations, it is likely that during the turn, the pilot experienced spatial disorientation, which resulted in an inadvertent descent, and subsequent impact with the terrain.

Verbatim NTSB analysis and probable cause from the NTSB dataset