Can only speak re the 737NG. Will autoland on single channel on the real airplane. Main differences from dual channel are :
Single channel autopilot authority only
Much reduced failure protections (e.g. no hardover protection)
No flare spring bias stab trim at 400 feet
Will not annuciate FLARE
No guarantees made as to performance (sink rates, position etc.).
Why is it available ? Its there because its lesser of two evils (i.e. if the pilot has let it go that far it might as well try and save his ass rather than disconnect).
DO NOT try this on a real airplane !!!! Its a safety net - not a certified function of the system. The AFM limits use of the single channel autopilot to 50 feet for good reason.
Last edited by sets; 14th Feb 2005 at 23:50.