PDA

View Full Version : RVR B & C not relevant


longobard
26th May 2008, 11:39
If during a CATII/III approach RVR B & C are considered as NOT relevant, can the approach be continued below the OM if they are reported as below 75mt? Or if Reported but not controlling the RVR B anc C points have to always be at least 75mt (125mt for B in case of no autorollout)?

Gillespie
26th May 2008, 13:03
If you can prove that you can cross the threshold at 50', land and decelerate to 60kts all within the touchdown zone, then the Midpoint/stop end RVR values are not relevant therefore theoretically you can continue. However - if the RVR is below 75m MP/STP end, then good luck on the taxi back to the terminal.

lederhosen
26th May 2008, 13:55
From a practical point of view you would need a set of very unusual circumstances for the mid point RVR not to be relevant. As the previous poster pointed out you need to prove that the aircraft can decelerate to a safe speed within the first sector for you to be able to continue the approach if the rest are below limits.

From my perspective in the real world on the 737 that means the speed I am comfortable taxiing in CAT 3 conditions, which is pretty slow. Stop end RVR on a lot of CAT 3 runways may not be relevant.

Out of interest are there autoland capable helicopters where this might be an issue or does anybody fly a CAT 3 machine that could do this?