2.9.5.55918 (MT) AFCS can be engaged with INS in ALIGN or OFF

[Stickler]

According to T.O. 1F-4C-1, 1 October 1970, p. 2-27 (see below), the AFCS cannot be engaged if INS is in ALIGN.

In the game, the AFCS and altitude hold can be engaged if INS is in ALIGN or even OFF. Also, AFCS does not disengage if INS is active and then set to ALIGN or OFF. With the INS in ALIGN or OFF, there is no apparent degradation in AFCS performance.

The note in the attachment cannot be found in any other F-4 manual available to me, so it is possible this limitation does not exist in mod states other than the ones the manual applies to, but it would seem logical that the INS is required for the AFCS to function.

This is supported by the checklist sequence (same for all F-4 variants I have checked) per which the reference system selector is to be set to PRIM (after the INS is in NAV) prior to checking the AFCS.

[WinOrLose]

Confirmation that this is still happening after latest patch.

[Stickler]

While it is still not entirely clear to me whether the AFCS could be engaged with the INS in ALIGN in later mod states of the F-4E, I stumbled upon two references that indicate that the AFCS might in fact operate independently of the INS, but that also indicates that AFCS dependencies are incorrectly modelled in another regard:

In the game, the AFCS can be engaged and remains engaged regardless of the position of the reference system selector switch or the compass controller switch.

The only aspect of relevant in-game behaviour that corresponds to the above logic is that the AFCS does in fact not disengage when the mode selector is switched from SLAVED to DG.

In this context, it is noteworthy that it is currently not possible to switch from SLAVED to DG directly using the mouse, since a left click will switch to COMP (and successively to DG), while a right click will switch to SYNC.

Edited January 25 by Stickler