"With the autopilot off, the autothrottle goes off at 5’."
A very interesting scenario indeed. I'm thinking misprint, and it should read... the autothrottle disengages (but remains armed) at 5' RA. Perhaps a B744 Avionics engineer could throw some light on this. Any out there?
I don't know if it's a misprint. I think that since TOGA is disabled below 5' for 2 seconds, there is also something that affects the A/T at this point. Or, maybe TOGA is disabled precisely
because the A/T is disabled.