Auto pilot on Cherokee

[flapsdown3]

Is someone able please to explain to me the Auto pilot settings in the A2A PA28-180 Cherokee.
The various settings of HD - LO - HI - ST ??
And when clicking on the Alt Hold, how does this work please? Is there anywhere on the aircraft
to set an altitude or does it just hold the current altitude the aircraft is at?
I have looked in the manual but can't find any explanation for this Auto pilot system.
Thanks
John

[AKar]

The various settings of HD - LO - HI - ST ??

HD: turn command is issued to follow the heading bug;

ST: "stabilizer" mode, allows you to set the turn rate target by rotating the knob at the upper left side of the unit, making highly convenient mouse wheel steering;

LO TRK: essentially a NAV hold, which commands turn to follow the NAV 1 indication, with low gains, in actual unit to avoid nuisance oscillations when following fluctuating signals. Note that there is no interception capability, just a capability to follow an established course, nor do the TRK modes, by design, negotiate any turns in the flight plan;

HI TRK: same but with higher gains, in actual unit to allow faster response when following sensitive signals, such as localizer or GPS source. In the sim, not sure if it really matters which one you use. And again, no intercept capability nor turn negotiation. Straight segment cruise control only!

And when clicking on the Alt Hold, how does this work please? Is there anywhere on the aircraft to set an altitude or does it just hold the current altitude the aircraft is at?

It holds the current pressure altitude at the time of engagement, there is no altitude select function. Nor does it follow your altimeter, so if your QNH changes significantly, you need to re-position the airplane vertically, and re-engage the altitude hold to correct. Note that the autopilot does not trim the airplane, which is simulated refreshingly correct here. You need to trim manually when under autopilot altitude hold as well, prompted by a system giving you a beep.

I have looked in the manual but can't find any explanation for this Auto pilot system.

With the autopilot (and other avionics) it is suggested to browse through the real-world manuals to find all the "hidden" details. For AP, try this one [pdf] for starters. System 30 information is applicable to this unit.

-Esa

[flapsdown3]

Thank you Esa. Much appreciated. Esa may I also ask you please? Is there a gauge anywhere in the cockpit that show flap positions? I have looked but can't find it.
Thanks.
John

[AKar]

Thank you Esa. Much appreciated

No problem. Feel free to ask should anything come into mind. In all its simplicity, the S-TEC 30 is a great and capable little tool when you learn to use it, and its inclusion into the simulation is nice because such a common older-school autopilot keeps you naturally in the loop, making sim flights much less boring.

-Esa

[lowflyr]

Thank you Esa. Much appreciated. Esa may I also ask you please? Is there a gauge anywhere in the cockpit that show flap positions? I have looked but can't find it.
Thanks.
John

There is no flap position indicator, per se. The flap lever itself is the indicator. When flying the real aircraft, a quick hand down to the lever will let you know how much flaps you have in (though I don't recall not knowing how much flaps I had in when flying). In the sim, sometimes it's not as easy to keep track of, but if you use TrackIR or VR, then a glance down at the lever will let you know where they're at.

[SJDobby]

Thank you Esa. Much appreciated. Esa may I also ask you please? Is there a gauge anywhere in the cockpit that show flap positions? I have looked but can't find it.
Thanks.
John

There is no flap position indicator, per se. The flap lever itself is the indicator. When flying the real aircraft, a quick hand down to the lever will let you know how much flaps you have in (though I don't recall not knowing how much flaps I had in when flying). In the sim, sometimes it's not as easy to keep track of, but if you use TrackIR or VR, then a glance down at the lever will let you know where they're at.

The main situations where you want a flap-indicator in the flightdeck are when you can't look over your shoulder to see the flaps are where you want them to be (e.g. in a larger aircraft where the wing's trailing edge is less visible to the pilot) or when the flaps are electrically/hydraulically operated (where the flap lever position might well be at odds with the actual flap position either due to a system failure or because there is a delay between flap selection and flaps moving to selected position).

Regards
Simon