I’ve been messing around with the Twin Otter and doing a lot of IFR. I see 2 localizers/glideslopes. One overlaid over the Artificial Horizon, and the other overlaid over the HSI.
The glideslope does not agree between the two, with the AH glideslope showing higher. The HSI GS is correct.
If the horizontal needle on the AF is not a GS, what is it? CDI was set to V/LOC.