GPSS option to Autopilot on SR20

Hi all,

Has any had a GPSS autopilot module added (GPS Steering) to a
SR-20 ‘B’ with the STEC-30 autopilot. I would be interested to hear

- costs
- usefulness
- positioning of switch etc.



We had the GPSS installed, but I don’t remember the cost. I’ve found it to be extremely useful. We had the switch mounted high on the panel to the right of the annunciator panel.

Not yet, but I’m on the schedule at Air Associates to have it installed in my “B” config (S-Tec 30, Century HSI, Garmin 430/420 combo) in a couple of weeks, along with an “A/B” switch to allow the GPS steering data to be fed into the unit from either Garmin. I’ve seen the GPSS/HDG switch and A/B switch installed in the center console, just to the left of the flap switch, but I don’t like them there (too much chance of hitting one of them by accident when I reach for the flap switch or throttle), so I’m having them installed in the blank space above the altimeter, where the alternator voltmeter selector switch is on “C” models. The installed cost, according to my quote, will be approx $1500.00. (1405.98 for the GPSS unit and installation, approx 100.00 for the A/B switch, depending on labor time required to make the extra wiring harness - one harness for the GPSS/HSI/S-Tec 30/GNS430 comes in the kit. The GNS430-plus-GNC420-to-A/B switch harness has to be made by hand.)

The usefullness of the GPSS steering, which I’ve used on a Piper and a Cessna, is to allow automatic, smooth, GPS-anticipated turns in approaches and course changes in complex flight plans. No more switching to hdg mode, making the turn, then switching back to trk mode after the HSI deviation needle centers up. Simply put, it cuts down on the “knob twiddling” enroute and on approach. (I prefer to hand fly approaches, but it would be nice to have as a backup if I was in a nasty situation - bad turbulence, night with VERY low ceilings, pax distractions, etc.) Plus, its my understanding that the GPSS roll-converter installation is about the only way to get autopilot-coupled course tracking out of the second Garmin (420) in “B” avionics installations.

Not on the ‘B’ config but I did install it on the ‘C’ SR20. One of the ealier model S-TEC 55s before it became the 55X and included the GPSS standard.

The module was just under $900 plus three-four hours to install if I remember correctly. In terms of functionality, the GPSS mode is what I use all the time for cross country flying. Works extremely well and makes flying a multi-leg course unbelievably easy.

Installed on that bare plastic area just to the left of the flap selector. Toggles either GPSS or HDG mode with a simple push button. Very clean install, looks great.

I just picked up my SR20 B model from the shop today after having GPSS installed. I have not had enough experience to say much except…I had the switch installed next to the flap switch. My main reason for putting it there was because I did not want to cut up the panel. However, after a brief flight, I think I would recommend the switch be put on the panel. The reason is that it is in your normal scan and you can see what mode you are in. I am sure I will get used to it, but the way I had it installed requires you to look down to verify what is going on.

I am embarrassed to say that I spent closer to $2000 than $1500 out the door.

It did seem to be very cool with the brief try out today.

David Raab
SR20 N224RF

I have an STEC30 with GPSS in my 260se–it’s a really nice combination and you won’t be disappointed. The capability offered by GPSS for the price is one of the outstanding values in GA today, IMHO.


It should default to the HDG mode on start up which works for most departures. From there you will normally push it twice during the flight, once when you switch to the GPSS mode for navigation and once again to the HDG mode when ATC starts vectoring you around on arrival.

Same number of time you use the flap switch if you think about it. Works well where you installed it and it is no more or less a part of your scan than the flap selector. Better location than the panel and cleaner installation.

Just my two cents.


Do not EVER be embarrassed about giving us information on cost. What you paid may be the only option where you are. It would be helpful to tell us where you had the work done so the rest of us could plan accordingly.

In reply to:

Works well where you installed it and it is no more or less a part of your scan than the flap selector.

Concur. I’m very happy with it in that position.