I'm having a problem with understanding that an A/P pb will physically engage in 'latched' ALT2 when it wouldn't engage during the period of time that the condition precipitating the latching was in effect.
AP was disconnected due to (dual) ADR loss, AS gains could not be established.
Once the (dual) AS returnes, the gains can be established again.
The AP has it own gains, rate- and amplitude limitations build in, it don't need the NORMAL LAW or whatever remaining protections in ALTERNATE.
AP commands a separate pitch deflection order for elevator (DQ) and THS(DQT) to FCPC in control.
For roll command there is a separate roll order(P) for ailerons and spoilers.
Yaw control command is separated in (Ytrim) and (Ystab).
All are
deflection! orders.
If you were able to get the A/P pb to engage in ALT2, what would the FMA displayed lateral steering mode be in roll direct? Same as roll alternate? Blank?
After 02:10:46 it would return in HDG or TRACK because that are the only SELECTED lateral modes available.
AFAIK with current HDG or TRACK as default.