GTN750 and AP APCH
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Trying to understand how the TDS GTN750 and the Bonanza AP are designed to operate, when using HDG mode to intercept an ILS LOC using APR mode.
My experience w/ Proline 21 and G1000/3000 systems, is that HDG mode is maintained while LNAV is "armed" until capturing the LOC. But with the Bonanza and the GTN750, when I activate APR mode, HDG is no longer "lit" on the panel, and the plane does not hold the HDG that was set when pressing APR.
Big Note - I have a Brunner force feedback yoke, and trying to find the right config for various aircraft is always a nightmare ... overly complex. But I have turned off AP and Trim on the Brunner setup to try to isolate it from any causal effect. Still, the same behavior.
Should the aircraft continue to hold the HDG until the needle starts to move (capturing the LOC signal)? I have HDG set to about a 30 deg intercept angle, but when I press APR the plane starts to reduce the angle and drift toward the LOC crs (prematurely).
Would appreciate any insights to help me troubleshoot. Thanks!
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You are correct about how the real aircraft should work, but autopilot mode arming has never been properly implemented in the native Flight Simulator code. The code that operates the autopilot today goes back to at least 1998. It's possible to create better mode arming by writing your own custom autopilot controller, but that falls on the shoulders of each GPS developer, in this case. I have implemented my own altitude and vertical speed arming in some aircraft (TBM, Starship, Baron Professional, Bonanza Professional), but the horizontal modes are a whole other can of worms.
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Yes, Working Title (who makes those avionics) have implemented their own autopilot system to get that behavior. The PMS50 GTN does the same thing. Other developers have chosen to use the native autopilot implantation. They both have their advantages and disadvantages as far as I'm concerned as an aircraft developer.
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Yes exactly. One GTN750 can do holds on airways (which is required in real life), the other (PMSS50) cannot. That's why I moved to TDS. But it sounds like you are saying the PMSS50 has its own AP logic which I would have to give higher weighting vs holds, so I will probably switch back. Win some and lose some. Regardless, your aircraft fleet are outstanding.
