Thanks YS.
Interestingly some Avro RJs are certificated to 150 m RVR from 50ft DH; the aircraft uses a dual channel ‘super’ fail passive auto-flight system. There is little or no additional crew training except that in the lowest visibilities there is no option to land following a system disconnect, a go around must be flown.
The basis of the JAA approved operation is given in JAR-OPS 1 Subpart E (For aeroplanes certificated in accordance with JAR-AWO 321(b)(3) or equivalent) and is called Cat3b.