Check your AFM, should be in Section 3.1 (Normal Procedures).
FlyingStone, I found it in the AFM. Thank you!
Autoflight section. It is also mentioned in the Systems Description of your FCOM stating (paraphrased) that for dual channel A/P operation, 2 AC generators are required.
vapilot2004, Your manual must be better than mine. Nothing in either volume of FCOM, unless I have overlooked it somewhere. But I had a good look.
I agree the engineers are a wealth of information.
But I think the question might not be is a Cat111 operation legal with one AC source, but rather will the aircraft actually DO an Autoland if coupled to an ILS and the A/P not disconnected.
In the first post I referred to a thread from 2002, here is a copy paste of a seemingly credible(?) poster. The info is from the maintenance manual.
During a dual channel operation, each FCC must be on an isolated power source. FCC A gets dc power from DC bus 1 and FCC B gets dc power from DC bus 2. Normally, the two dc buses are connected with the bus tie relay. If either FCC is in the active G/S mode (ie when glides slope captures),it will cause the bus tie relay to open. This will separate the DC power sources to the two FCCs.
What happens when the Bus Tie Relay Opens and why does it open?
When EITHER the 'A' FCC or the 'B'FCC is in the G/S active mode it tells the IFSAU (just a control and comparison computer)
to isolate the DC Buses. The IFSAU needs confirmation from the Standby Power Control Unit that the power is normal by providing a ground to the IFSAU.This causes the G/S engaged position to be activated in the IFSAU and cause the ground to be removed from the bus tie relay.
If the Bus Tie Relay has a ground from the IFSAU then the relay closes and the DC Buses are connected together, when the ground is
removed the rely opens and the buses are isolated.
The Bus Power Control Unit which comprises of the TR's usually get their power from different 115v ac buses (AC Bus 1 & 2).If the TR's suddenly get their power from one source ie when a transfer occurs the Bus Transfer Control Unit knows where the source of power is from (either the generators or the APU generator). It therefore knows that even though both buses are powered it is from a single source. It therefore sends a signal to both FCC's that the DC Buses cannot be isolated. Both FCC's now removes the flight director as it does not have its required redundancy for the Dual Channel approach.