way , ▁there ▁is ▁just ▁a ▁visual , ▁“ black - hole ”. ▁ ▁Pil ots ▁too ▁often ▁confident ly ▁proceed ▁with ▁a ▁visual ▁approach ▁instead ▁of ▁re lying ▁on ▁instruments ▁during ▁night time ▁land ings . ▁ ▁As ▁a ▁result , ▁this ▁can ▁lead ▁to ▁the ▁pilot ▁experien cing ▁gli de ▁path ▁over est imation ▁( G PO ) ▁because ▁of ▁the ▁lack ▁of ▁peri pher al ▁visual ▁c ues , ▁especially , ▁below ▁the ▁aircraft . ▁ ▁In ▁addition , ▁with ▁no ▁peri pher al ▁visual ▁c ues ▁allowing ▁for ▁an ▁orientation ▁relative ▁to ▁the ▁earth ▁there ▁can ▁be ▁an ▁ill usion ▁of ▁the ▁pilot ▁being ▁u pr ight ▁and ▁the ▁run way ▁being ▁t ilt ed ▁and ▁s lop ing . ▁ ▁As ▁a ▁result , ▁they ▁initi ate ▁an ▁ag gress ive ▁descent ▁and ▁wrong ly ▁adjust ▁to ▁an ▁unsafe ▁gli de ▁path ▁below ▁the ▁desired ▁three - deg ree ▁gli de ▁path . ▁ ▁Aut ok ines is ▁▁▁ ▁The ▁aut ok in etic ▁ill usion ▁occurs ▁at ▁night ▁or ▁in ▁conditions ▁with ▁poor ▁visual ▁c ues . ▁ ▁This ▁ill usion ▁gives ▁the ▁pilot ▁the ▁impression ▁that ▁a ▁station ary ▁object ▁is ▁moving ▁in ▁front ▁of ▁the ▁air plane ' s ▁path ; ▁it ▁is ▁caused ▁by ▁st aring ▁at ▁a ▁fixed ▁single ▁point ▁of ▁light ▁( ground ▁light ▁or ▁a ▁star ) ▁in ▁a ▁totally ▁dark ▁and ▁feature less ▁background . ▁ ▁The ▁reason ▁why ▁this ▁visual ▁ill usion ▁occurs ▁is ▁because ▁of ▁very ▁small ▁movements