737 Autoland 'SINGLE CH' FMA
 

I'd be grateful if a 737 type rated person could clarify the FMA sequence on fail operational equipped ILS autoland approaches.

Most 737 NG's are equipped with fail passive autoland equipment which annunciates 'SINGLE CH' after arming APP and selecting the second autopilot. SINGLE CH remains annunciated until after passing 1500ft when Flare arms and SINGLE CH is replaced by CMD when the second autopilot engages

Some 737's use the inertial source of the ISFD to provide a Fail Operational Cat IIIb capability and I'd like to know if SINGLE CH still gets annunciated until after 1500ft, before being replaced by LAND 3, or does CMD stay annunciated until the LAND 3 caption? I've seen videos of both sequences on a CAT IIIb equipped 737 so am wondering whether it depends on which software version the EFIS has?

On a Fail Operational aircraft the Single Channel annunciation changes below 1500ft to LAND 3 or LAND 2 and the second autopilot engages. The rudder channel engages and an autopilot go around is available. FLARE and ROLLOUT are also armed and annunciated on the FMA in white when armed and then green when active

Thanks for confirming this