Let’s assume for a moment that, since I haven’t actually tried the Twotter on an ILS approach, AP or otherwise, that the Islander, and the Twotter behave in the same incorrect way.
Also assume that the primary issue is one of pitch.
I just checked the AI.cfg for four different aircraft. the Asobo 172, PMDG DC-6, Aerosoft Twin Otter, and the BBS BN2 Islander:
172
pitchPID = 2.0, 0.1, 2.0, 10.0, 100.0
DC-6
pitchPID = 1.0, 0.5, 8.0, 1.0, 100.0
Twin Otter
pitchPID= 1, 0.01, 2, 0.6, 5
BN2 Islander
pitchPID= 1, 0.01, 2, 0.6, 5
Interestingly, both the Islander, and Twin Otter have exactly the same values for their “pitchPID”.
From the SDK entry:
PID
Input is the desired pitch, output is the pitch control input.Default is:
1.0, 0.01, 2.0, 0.6, 5.0
It looks like both BBS, and Aerosoft used the default for this setting, and both have AP control issues.
Let’s check one more, the SWS Kodiak:
pitchPID = 2, 0.1, 10, 1, 100
Again, non-default values, however I have to stress I’ve not tried an AP ILS approach in the Kodiak either, but I’m willing to bet that it works!
I know the Islander has had some issues with heading control as well, RNAV approaches for instance, so I took a look at the “headingPID” as well.
Default values from the SDK:
1.0, 0.01, 1.0, 1.0, 20.0
BN2 Islander
headingPID= 1, 0.01, 1, 1, 20
Twin Otter
headingPID= 1, 0.01, 1, 1, 20
172SP
headingPID = 2.0, 0.01, 2.0, 0.2, 1.0
DC-6
headingPID = 1.0, 0.01, 1.0, 0.2, 1.0
Again, defaults for the Islander, and Twin Otter, but not for the 172SP or DC-6.