Optical Illusion? Need PAPI or VGSI?
The 1996 767 accident, reported by TSB, noted the optical illusion of the sloping runway. Its not that this approach needed a glide slope - to what several hundred feet HAT, or a GPS, because the same illusion would affect the final few hundred feet of the visual segment - but it may indeed be helped in the visual segment - so why not PAPI/VGSI?