Originally Posted by el !
When is that the FMA displays "CAT 1" ?
Only when aircraft systems are degraded. Under normal circumstances it always displays CATIII dual (fail-operational autoland and roll-out). With engine out, the capability is still CATIII. Typicial reason to degrade would be unavailability of back-up systems such as loss of one ILS receiver.
Originally Posted by el !
Is autolanding still selectable in "CAT 1" on the Airbus even if it shouldn't?
Technically no, because there is no such selector. Keeping AP on below 150 (?) feet with CAT I memo is outside limitations for AP use.
Originally Posted by el !
Does the FMA it ever display "CAT 2" ?
Yes, but again only as a result of failed onboard equipment. For instance both autothrust channels, one radio altimeter or one Flight Mode Announciator display itself.
Originally Posted by el !
after landing, is the APPR mode and related light supposed to disarm automatically ?
No, it remains on to provide automatic rollout.
Cheers,
FD (the un-real)