The “Black Hole” Night Visual Approach: Calculated Approach Paths Resulting From Flying a Constant Visual Vertical Angle to Level and Upslope Runways

Abstract

Black hole" visual approaches have resulted in numerous off airport accidents. A tendency to fly a constant visual vertical angle to the runway lights might be one possible cause. Constant vertical angle (CVA) visual flight paths are calculated, showing the effects of starting altitude and distance, runway length, shape, and slope. Results are compared to published simulator studies. CVA flight tendency over level terrain cannot cause flight into the ground miles distant from the airport, except approaching an upsloping runway. Approach strategies for light aircraft to avoid this psychological phenomenon are indicated. A template for accident investigation use is illustrated.Night visual approaches in clear weather over dark territory to lighted airfields with no glideslope indicator have resulted in a high number of accidents characterized as controlled flight into terrain (Gibb, 2007;Kraft, 1978). Remarkably, many of these accident impact sites have been several miles away from the runway threshold. In one survey of 141 experienced instructor pilots averaging over 2,886 hr flight time, 79% had experienced the black hole illusion (defined as flying too low in a clear night visual approach) an average of 12 times each (Sipes & Lessard, 2000). It has been suggested that approaches to upsloping runways and rising ter-