Small Aircraft; Low Wing; 1 Eng; Retractable Gear
Flight Crew Private
Flight Crew Last 90 Days 32; Flight Crew Total 1400; Flight Crew Type 400
Situational Awareness
Inflight Event / Encounter CFTT / CFIT
General None Reported / Taken
Airport; Human Factors
TSP Runway 11 straight-in approach crosses a 4;251 foot elevation ridge about 6;400 feet from runway threshold (4;000 MSL). The ridge has a single steady red obstruction beacon that is located on the ridge crest at the intersection with the extended runway centerline. TSP had a PAPI installation for the runway that was deactivated after local pilots flew the PAPI in daylight and noted that the approach angle barely cleared the ridge- by about 25 feet.This night approach was flown with that awareness: the runway lighting was turned to maximum which includes REIL. As part of the visual approach method; the approach area west of the REIL was kept in constant sight. Touchdown point objective was about 20 feet past the numbers.During the approach the red obstruction beacon was difficult to see with low contrast to other lights in the area.Approach planning was flawed- basically the PAPI angle approach (noted above) was flown; uneventfully; but terrain was visible in the beacon flash to the left and above the aircraft and the ridge was visible for about .25 sec as the landing light swept across. The sudden very close proximity to the terrain was not anticipated.With higher winds; a significant downdraft and turbulence develop on the lee side of the ridge; potentially increasing the CFIT hazard for a low performance aircraft or an inadequately responsive pilot.Facility recommendations: the beacon is dim and needs to be replaced with a brighter light; and an additional light needs to be placed at the higher ridge top to the north. PAPI needs to be re-activated with an approach angle that provides at least 100 feet of vertical clearance.From an approach planning perspective: a right pattern staying inside of the hill would reduce the risk. But the straight-in risk would remain for the pilot with some operational requirement for a more immediate landing; or a pilot unfamiliar with the area. Garmin terrain warning activate immediately after clearing the ridge.
GA pilot reported the PAPI angle in use at TSP narrowly clears a ridge on approach to the runway.