The major changes in the HUD/PCA interacion, which includes Master Modes are as follows:
There are Four Master Modes:
Ground: Automatically selected when the aircraft is Weight-On-Wheels
NAV: Default mode, automatically selected when the aircraft is off the ground. It has three submodes: Normal, Approach (APP) and TD/RD.
AA: (Air Attack mode) which can be selected via HOTAS and PCA. It has four submodes: CAN (HOTAS), MAGIC (HOTAS), S530D (PCA) and POL (PCA).
AG (Ground Attack mode) which is selected via HOTAS. All AG weapons are selected via PCA but system remains in NAV until AG is enabled via HOTAS. It has five submodes: CAN, BL, BF, EF and RKT.
The AA CAN (guns) and MAGIC modes are a special setting. The aircraft is in self-defense mode and the radar is set to ACTIVE mode if it is in SIL.
AA guns and MAGIC missiles can only be selected via HOTAS and not by PCA. MAGIC button in the PCA changes MAGIC seeker search patterns, but do not select the missile.
Using the Special Modes switch will also place the aircraft in Self-defense mode and activate the radar if it is in SIL.
This behavior is completely different as to how it is currently coded, so it requires MAJOR rewrite.