Originally Posted by
FlyingFlight
I would separate two aspects, the legal and the Autopilot’s certified capabilities. For this I am assuming the runway is clear and with a CAT III installation.
From a legal perspective, if you need to have Automatic Rollout to have certain minima (75m vs 175m or No DH vs 50RA) then the system capability displayed when you arm approach is CAT3DUAL(and of course taking those non monitored systems into acount), and the crosswind needs to be within the 15kts limit. What happens when you have CAT3DUAL displayed but crosswind is 16-20kts? Then you would have to apply the minima applicable to an Automatic Landing without Automatic Rollout, which will probably be higher, and disconnect the autopilot once you’ve touched down(I cannot be certain about it as my operator has a 15kt crosswind limit for manual rollout so I haven’t been explained how to get advantage of those extra 5kts of crosswind, but there are AC where the limitation for automatic rollout is more than 15kts and this logic is applied on the inverse, so it makes sense).
From the autopilot capabilities point of view, let’s say you only have one AP operative and thus are limited to CAT3Single. If the crosswind is 15kts or bellow, there will be no damage to keep the AP on after landing, it will not disconnect on its own and should be able to handle it happily. But, once again, if the crosswind is above the 15kt threshold, the AP is certified capable of decrabing the AC but not of keeping it on the runway, and you should take over once you’re on the ground. Same logic applies to CAT2 system capability, the AP should handle happily a 15kt crosswind on rollout, but not a 20kt one.
Thank you for your reply
I wanted to know where in FCOM is it given that CAT 3 single is without rollout and CAT 3 DUAL is with roll out