S-Tec 3100 autopilot STC for the DA40

[Tim H]

From the brochure:

"The S-TEC 3100 features GPS Steering (GPSS), which enables the aircraft’s GPS navigation system to accept roll steering commands from the system. The end result is extremely accurate, “hands-off” GPS navigation in high-workload situations. Additionally, by accepting commands directly from the GPS, the GPSS function enables the S-TEC 3100 to not only fly very precise GPS courses, it also does an equally exceptional job of flying very precise, very stabilized GPS and missed approaches. "

Would this feature be available to G1000 Non-WAAS DA40's?

I had a 182RG with an S-TEC autopilot and a Garmin 430W. The GPSS was impressive. It would fly the entire missed approach including the hold completely hands free.

Would we remove the "hidden" turn-coordinator?

Thanks for assembling all the questions.

[Charles]

I exchanged a few emails with S-Tec. They confirm their interest to do an STC for the DA40 provided they get 15 orders for the system. There is no financial commitment until the STC is done, i.e. no upfront downpayment and cancellation with no penalties if done before the STC is issued. Orders placed before the STC is issued will get a 3-year warranty instead of the usual 1-year warranty.

This should be of great interest to DA40s without autopilot but also to all KAP 140-equipped DA40s due to the superior features of the S-Tec 3100. To quote them: "The S-TEC 3100 is a fully digital, attitude based, 2-axis autopilot with automatic pitch trim as standard. It has been designed to be compatible with modern EFIS systems and older analog panels alike, and includes features such as GPS Steering, Indicated airspeed hold, straight and level recovery, envelope protection and altitude preselect. The internal AHRS source allows the 3100 to be installed into aircraft with no external attitude sources and is also ready to accept digital information from any future avionic upgrades." With GPSS, the autopilot will fly a full approach, missed approach and a hold.


A few answers from S-Tec:

- It is fully compatible with the KI-525 HSI
- It has its own internal AHRS so does not require a turn coordinator
- Although not done yet, they are planning a G1000 interface which will be copied from the one they did for the S-Tec 55X.
- GNS and GTN navigators are fully supported.
- Aspen and G500 are fully supported
- Bendix King servos cannot be reused. The price includes 3 new servos.

I have asked a ton of other questions and got great answers so if you have any other questions, let me know, I will get the answer.

I will place an order myself. They need 15 to guarantee the DA40 will be their next STC.

Anyone else interested?

[blsewardjr]

That's great news.

[JohnLand]

will there be a yaw damper option?

[blsewardjr]

I did a quick price comparison with the Garmin GFC500 autopilot, which is not available for the DA40 but provides a price comparison for a comparable autopilot. Assuming the 16K STEC 3100 comes with three servos and everything needed to interface with the Garmin G530, the price differential for steam gauge DA40s may not be as large as it first appears. While the Garmin autopilot alone sells for only 7k, we would also need additional devices. Specifically, we would need a G5 AI (which is also not currently approved for the DA40) to provide AHRS (2.2k), a third pitch servo for pitch trim (1.7 for the certified version based on the cost difference for 2 versus 3 at Sarasota Avionics), and a GAD 29B interface for the Garmin Nav/Com (.5K), for a total of 11.4K before installation. The actual price delta would appear to be less than 5K.

[Charles]

From S-Tec:

“Yes, the 3100 does have yaw capability. If the DA40 would benefit from a yaw system then we can add that to the STC quite easily.”

[skywardcon]

Any chance this STC could cover the DA42's with the Kap-140?

[nrenno]

What is the cost of the S-TEC 3100 including servos and installation?

[Colin]

I would think that the control forces being so different on the DA42 it would be a non-starter. The price would have to be higher.

I also think you'd be much better off putting that money toward a GFC-700 which offers the yaw-damper and flight level change. And, eventually, envelope protection.

[Charles]

That’s what I thought as well but went to the source for confirmation:

“Typically twin engine aircraft will be on a separate STC project because the added thrust and varying flight characteristic means the difference in autopilot configuration will be significantly different. I will let you know when I get any confirmation on this.”