I have a 1980 M5-235 without an autopilot. After a few trips out west and one to Alaska I’ve decided to investigate installing one (we’re talking about Alaska again in 2021). Looks like S-Tec is about my only option (not interested in a Century). I didn’t find the drawings for servo installation on my parts CD and am not sure which models are approved.

Have any of you installed an S-Tec? Can you tell me what’s involved? Drawings available? Are there any other options?

Thanks,

Chip

Any idea what you think it's going to cost in total? Just curious.

Rezrider wrote: ↑

Fri Sep 18, 2020 8:12 am

Any idea what you think it's going to cost in total? Just curious.

That's one of the things I'm trying to figure out. I'm hoping to find used parts and have help available for the install. If it costs north of $15k then I'll abandon mission.

I can only talk about the STec that was installed in my Maule M5 when I bought it. Single axis AP. And all it controls is the rudder pedals (which is about as cheap of a AP as you can get). It works in very light turbulence but beyond that it's not that great. I think I've seen this AP used forsale for around $1k-$2k. Don't know if I would pay much more for it.

To install it seems pretty easy. Just a single servo back in the tail that clamps onto the rudder cables. Then the wing level gyro and AP control head. It taps into your DG heading bug and also takes in a nav source. I've got my hooked into my GNS430w, though I mostly just use the heading bug on the DG.

There's a thread i started about A/P on my M4. I had the Century !! A/P on my M4 from the factory. All it had was an aileron servo in the right wing. I'm in the middle of a full restoration and removed the servo since it's not supported anymore.

I was interested in the S-Tec too, but heard from several owners that the roll control is not good in turbulence due it using the rudder vs aileron.

I'm still hoping Garmin or Dynon will come out with an STC for the M4/M5.

I was really hoping for Garmin but have almost given up. Our aircraft are not in the “in the works” or the “expect to start in the next twelve months” list. A Garmin rep a while back told me that inquiries helped and if someone volunteered an airplane it would help. He also said they would probably like to start with higher model and easy to add lesser horsepower models. So, which one of you jokers with a M7-260 or M9 wants to volunteer?

Just finished GFC500 install in an older 182 and it is a pretty awesome unit.

You will not be able to buy used STEC A/Ps and just install them.
The STC for the A/P is N number specific and STEC will not allow a change in N number unless the A/P goes back to them for "recertify" Very costly
Also for certified airplanes only an authorized shop can install them per STEC.

Sounds right about S-Tec. Protect their dealers very well. Last year installed a 55x in a Navion. The Navion society had gone to S-Tec and asked for an autopilot approval. They had a group of 55x units which had been returned for one reason or the other and repaired them and certified them For the Navion. Came with a sticker on the bottom of the Unit which said repaired, not even refurbished or overhauled. Ended up sending the unit we received back for repair again before it work. Pulled my hair out but finally worked pretty well. Two big old bundles of wires compared to the little old cable for the Garmin but you take what you can get in this industry.

Out of curiosity, is this only a problem for M4/5 or are later maules plagued by a lack of autopilot options?

DELETED. Info may have been wrong.

I might be interested if there's a group forming to get an STC going. I see that TruTrak has a reasonably priced one STC'd for Piper and Cessna models. They were bought by Bendix... perhaps it's an option?

I too looked at an autopilot recently... Although the plane does trim out nicely, this year we did 2 trips each trip was 1,000 miles from home. Autopilot would have been very nice to have. Therefore S-Tec 30-2 was priced out for my 1999 M7. Very expensive ..ie north of 20K once bought and installed. We need the factory to push Garmin to add their autopilot to new planes and let us then jump on this bandwagon. The unit sells for almost 6K less for the equipment.

If certified one should get a pair of G5s with 29B and Gmu11 as well as the GFC500 installed in the low 20s.

I'll rock the boat and say "it's a bush plane, why does it need an autopilot?"
The added weight? Not to mention the fact you can buy a lot of avgas for $20k.

Heck, for $20k, you can just pay me to fly it wherever you want to use it, and have plenty left over to take the airliner to meet me at the other end!

Just kidding. I fly bush planes for a living, and I love using the autopilot in the ones that have it. Of course, I didn’t have to pay for it...