Originally Posted by
chevvron
Some individual aircraft may be approved for 'Lower Than Cat 1 Minima' approaches where only Cat 1 ILS is available but I think this only involves RVR=300m instead of 550m; DH remains 200ft but Cat 2/3 approach and runway lighting is not required.
Head up display can reduce RVR I believe, don't know for sure as it's not fitted to aircraft of the age I fly.