WPR16LA093 · Cessna 172 K

The private pilot and non-pilot rated passenger departed for a personal flight to an island airport located on top of a plateau. While on final approach for landing, the airplane descended below the elevation of the runway threshold. The pilot attempted to conduct a go-around but was unable to prevent a collision with the rising terrain. Detailed examination of the airframe and engine did not reveal evidence of any pre-impact mechanical deficiencies or failures that would have precluded normal operation.

The airport's website contained information for pilots about its unique operational hazards. The website explicitly warned that there were no visual cues for altitude reference on approach, that there was usually a strong downdraft near the approach end of the runway due to the surrounding terrain and prevailing winds, and that the upslope of the runway could cause approach and flare difficulties for inexperienced pilots. The website further stated that most flying clubs required pilots flying into the airport for the first time to be accompanied by a flight instructor or another pilot familiar with the airport.

The pilot reported that the accident flight was his first experience flying to that airport, and that neither his co-owners of the airplane, nor his insurance company, required any checkout flight to that airport. He reported that he was only vaguely aware of the visual illusions associated with the landing approach; and that he was unaware of, and never saw or used, the pulsating visual approach slope indicator (PVASI) with which the runway was equipped. Review of onboard GPS data revealed that the pilot flew a straight-in approach, instead of the normal and recommended right traffic pattern. The airplane joined the final approach course about 1.4 miles from the runway threshold and about 100 ft below the nominal approach path slope. The airplane descended farther below the nominal approach path and remained in the PVASI flashing red (well below course) indication zone for the entire approach. The pilot initiated the go-around about 8 seconds before impact, as the airplane descended below the elevation of the threshold.

The pilot's incomplete preparations for the flight, particularly with regard to the airport's peculiarities and associated hazards, resulted in the pilot conducting an inordinately low final approach. Had the pilot flown the recommended traffic pattern instead of a straight-in approach, he would have provided himself with another opportunity to detect the airport's unusual characteristics and conduct his final approach accordingly. Finally, ground and wind speed data suggest that the airplane was near or at the extreme low end of its normal approach speed range just before the go-around. In combination, these factors placed the airplane in a position and energy state from which recovery was difficult or impossible once the airplane encountered the known downdraft phenomenon just short of the runway threshold.

Verbatim NTSB analysis and probable cause from the NTSB dataset