height ▁Once ▁established ▁on ▁an ▁approach , ▁the ▁pilot ▁follows ▁the ▁I LS ▁approach ▁path ▁indicated ▁by ▁the ▁local izer ▁and ▁desc ends ▁along ▁the ▁gli de ▁path ▁to ▁the ▁decision ▁height . ▁This ▁is ▁the ▁height ▁at ▁which ▁the ▁pilot ▁must ▁have ▁ade qu ate ▁visual ▁reference ▁to ▁the ▁landing ▁environment ▁( e . g . ▁approach ▁or ▁run way ▁light ing ) ▁to ▁decide ▁whether ▁to ▁continue ▁the ▁descent ▁to ▁a ▁landing ; ▁otherwise , ▁the ▁pilot ▁must ▁execute ▁a ▁missed ▁approach ▁procedure , ▁then ▁try ▁the ▁same ▁approach ▁again , ▁try ▁a ▁different ▁approach , ▁or ▁di vert ▁to ▁another ▁air port . ▁ ▁I LS ▁categories ▁ ▁Sm aller ▁aircraft ▁generally ▁are ▁equ ipped ▁to ▁fly ▁only ▁a ▁C AT ▁I ▁I LS . ▁On ▁larger ▁aircraft , ▁these ▁approaches ▁typically ▁are ▁controlled ▁by ▁the ▁flight ▁control ▁system ▁with ▁the ▁flight ▁crew ▁providing ▁super vision . ▁ ▁C AT ▁I ▁re lies ▁only ▁on ▁alt imeter ▁indic ations ▁for ▁decision ▁height , ▁whereas ▁C AT ▁II ▁and ▁C AT ▁III ▁approaches ▁use ▁rad ar ▁alt imeter ▁( RA ) ▁to ▁determine ▁decision ▁height . ▁ ▁An ▁I LS ▁must ▁shut ▁down ▁upon ▁internal ▁detection ▁of ▁a ▁fault ▁condition . ▁High er ▁categories ▁require ▁shorter ▁response ▁times ; ▁therefore , ▁I LS ▁equipment ▁is ▁required ▁to ▁shut ▁down ▁more ▁quickly . ▁For ▁example , ▁a ▁C AT ▁I ▁local izer ▁must ▁shut ▁down ▁within ▁ 1 0 ▁seconds ▁of ▁detect ing ▁a ▁fault , ▁but ▁a ▁C AT ▁III ▁local