Update: Good news, I managed to mitigate my issues with the Autopilot Approach Hold not holding altitude on Localizer/Glideslope intercept(it now works perfectly!). I edited the A/P entry in the aircraft config file using known stable parameters but also, on the A400M's vast A/P and Display Function brow, it is very important to make sure that the NAV/GPS button is off(not illuminated) prior to activating the Approach Hold function! The ILS frequencies can be adjusted/switched in the upper display on the brow above the primary ND/MFD(left of the A/P control unit).
View attachment 5945
Here is the Autopilot entry I am using:
[autopilot]
autopilot_available= 1
flight_director_available= 1
default_vertical_speed= 500.00
autothrottle_available= 1
autothrottle_arming_required= 1
autothrottle_takeoff_ga= 1
autothrottle_max_rpm= 100.00
pitch_takeoff_ga= 15.00
use_no_default_pitch = 1
use_no_default_bank = 1
default_pitch_mode=0
default_bank_mode=0
max_pitch= 15.00
max_pitch_acceleration= 1.00
max_pitch_velocity_lo_alt= 0.75
max_pitch_velocity_hi_alt= 0.35
max_pitch_velocity_lo_alt_breakpoint= 7000.00
max_pitch_velocity_hi_alt_breakpoint= 25000.00
max_bank=30,25,20,15,10
max_bank_acceleration= 3.50
max_bank_velocity= 6.00
max_throttle_rate= 0.30
nav_proportional_control= 9.80
nav_integrator_control= 0.20
nav_derivative_control= 0.00
nav_integrator_boundary= 0.20
nav_derivative_boundary= 0.00
gs_proportional_control= 30.00
gs_integrator_control= 0.75
gs_derivative_control= 5.00
gs_integrator_boundary= 0.50
gs_derivative_boundary= 10.00
yaw_damper_gain= 1.00
Off to perform a final cross-country check flight to see if everything works(NAV/GPS/ILS)