Admittedly here we are close enough to see the approach lights
but if one watches the runway aspect ratio and keeps that constant, why should there be a problem?
I see lots of pilots fly really low approaches in broad daylight, dragging the plane in at high power, and with the plane’s shadow showing right underneath it so obviously they are very low. That’s not going to work well at night, but that’s a different issue.
I thought of the black hole effect not as a problem of being low/high, but of how far you are from the runway. The illusion is you think you are farther away than you really are and don’t initiate the flare in time, “crashing” into the runway. Or you delay speed reduction / flap extension until too late etc.
I was hit by the black hole effect once on a visual approach over water to a runway without either ILS or PAPI/VASIS. I had been flying only by visual reference to the runway and when I checked the altimeter I was dangerously low. (Something like 300 ft AGL more than 2 miles out.)
Peter wrote:
but if one watches the runway aspect ratio and keeps that constant, why should there be a problem?
If you mean the angle Grenlights – red lights, that is exactly what the problem is. Geometrically, if you want to keep that angle constant, you can go down in a straight (descending) line, but rather in a curved shape (not sure if an arc / elliptical / hyper…, geometry is not my forte).
See picture above. At B normal, your relative angle is much higher than at A, so keeping the constant angle would bring your closer to A low (and the ground)
Looks like an arc of a circle actually (Theorem of inscribed angle):
Locus of points seeing a segment under a constant angle
A-B would be your runway. Obviously, a 3% angle will make the circle very big, and the arc of the circle a more “normal” flying shape.
Been studying vfr night lately. They talk abot the grey spot “issue”, but I guess the black hole is a different issue altogether ? 
Should not be a problem on single engine with a 5km runway as you would call it quick undershoot
I see it more of an issue of not flaring at the right height above the runway at night.
I think so too… I don’t see why the aspect ratio (width to height) of the “picture” should change as you get nearer to it. It must be some more specific optical illusion which is operating here.
Also, the standard principle of keeping the “picture in the window” constant all the way down should apply.
Flaring is a different problem. I noticed that during instructor revalidation they make them land at night with the landing lights off. Or maybe that is a UK-only thing?
Peter wrote:
Flaring is a different problem. I noticed that during instructor revalidation they make them land at night with the landing lights off. Or maybe that is a UK-only thing?
When I did my night VFR training I had to do landings with the landing lights off. Of course that was before EASA.
Surprisingly enough, part-FCL doesn’t appear to include a night rating syllabus for airplanes — only for helicopters!
