Cessna P210 N6500W accident near Prescott, Arizona

Probable cause

The pilot's misjudgment of distance and altitude from the runway and his subsequent failure to maintain an approach path that provided clearance from the terrain due to a visual illusion in dark night conditions.

NTSB analysis

The purpose of the flight was for the pilot to acquire night currency by performing practice takeoffs and landings. He initially requested to takeoff and fly the traffic pattern for the longer, 150-ft wide runway (21L), but the ground controller replied that the traffic pattern was full and offered that the pilot could use the parallel, shorter 60-ft wide runway (21R). Once airborne, the pilot did not fly a traffic pattern that paralleled runway 21R on downwind and he overshot the final approach course on his base-to-final turn. The pilot subsequently corrected his track and became aligned for runway 21R, but airplane collided with desert terrain about 1,900 ft short of the destination runway, impacting in a near level-pitch attitude with the landing gear down. The airplane impacted a berm and shortly thereafter, was destroyed by a postcrash fire.

Although visual meteorological conditions prevailed, no natural horizon and few external visual references were available during the visual approach in dark night conditions to judge height above terrain. The pilot's tasks during the approach included maintaining visual separation from the traffic on runway 21L and aligning with the much narrower runway 21R. The pilot’s collision with terrain short of the runway suggests that he was experiencing the runway width illusion in which the sight picture to a narrow runway during a nighttime approach can lead pilots to believe their approach path is too high and they descend in an attempt to correct. The runway had a precision approach path indicator (PAPI) system to help pilots maintain a safe glidepath at night. The pilot’s competing visual task demands including traffic and runway alignment and recency of nighttime experience may have contributed to his failure to heed this information.

Examination of the recovered wreckage did not reveal evidence of any preexisting mechanical anomalies that would have precluded normal operation of the airplane. Examination of the airplane's exhaust revealed a crack that would have likely been present during the most recent maintenance. However, although the heat exchanger contained voids, that was likely not an entry for the exhaust gases because the higher pressure of the ram air that is directed into the exchanger.

Postmortem toxicology tests identified 35% carboxyhemoglobin (carbon monoxide) in the pilot's blood. The soot deposits in his airways suggests the elevated carbon monoxide was a postcrash effect rather than occurring before the airplane collided with the ground. Therefore, it is unlikely that the effects of carbon monoxide contributed to the accident. The circumstances of the accident suggest the pilot was actively flying the airplane, indicating he was not incapacitated at the time.

Text from the NTSB. Open the NTSB docket for WPR18FA245 for the full record.