Nice. You will find that the Aspen is the best use of money in avionics you can find. Nowhere else you get that much for your investment. S-TEC is just the only game in town so it’s moot to discuss how good or bad it is. The Avionik Straubing altitude preselect works be “pushing” altitude hold when it has reached the selected altitude. That means oscillation. You should have asked me, I have an S-TEC altitude preselect sitting on my shelf, that one is much better as it adjusts the climb/descent rate as it approaches the target altitude. 
Hi Achim,
we had the test flight yesterday and the test crew were very happy with the autopilot performance, in fact the test pilot knows the S-Tec 55x very well from his Cirrus installation (which he upgraded to the Avidyne) and sais that he finds this installation to be much better. They tried several altitude captures as well as one LPV approach and one ILS and came back very happy indeed. He said that he was very surprised about how well the autopilot works and how it is implemented. I don´t know if the Straubing box has in the mean time received added functionality or if they have found a better way of doing it
I don´t know if the Straubing box has in the mean time received added functionality or if they have found a better way of doing it
No, it’s still the same. It works OK when your vertical speed is slow. The S-TEC altitude preselect (ST-360) is ridiculously expensive which is why it is seldomly installed these days. I was very lucky to have gotten it for 500 € from somebody who installed another autopilot. Only used it for a year until the Avidyne DFC-90 became available. Will pass it on one day to a worthy pilot.
After drooling over Mooney Driver’s refit, I did a bit more googling on the original topic (what proportion of IFR GA aircraft are LPV capable) and found this writeup related to FAA outline plans to change their airway structure, with an interesting bar chart of equipage on V-routes today. Seems that around 80-90% of IFR GA aircraft are “Advanced RNAV” equipped (i.e. WAAS). Much higher than estimates given earlier in this thread.
European equipage percentages may be different, but without access to real data (eg derived from flight plans), nobody can know for sure.
I have to say the proposed approach to airspace evolution sounds very sensible to me.
DavidC,
The 80% that are equipped to fly the T routes does not imply WAAS capability, just GPS enroute or terminal capability. This is also not a fleet equipage, but how aircraft flying IFR using V routes are equipped. The vast majority are not WAAS capable and are filing US domestic flightplan forms (NAS) where G is specified for the equipment code. Unlike ICAO, the NAS flightplan form combines all the equipment codes into a single letter, so G means the aircraft has at least GPS certified for enroute and terminal operations. It doesn’t have anything to do with WAAS nor any specific approach capability. T routes are RNAV 2 routes and are approved in the US for all GPS units that have terminal and enroute IFR certification. Any aircraft filing a NAS flightplan with G for equipment or an ICAO flightplan with G may be assigned a T route. In order to file and use RNAV 1 routes in the US (RNAV SID or STAR), the equivalent of PRNAV routes elsewhere, one must use an ICAO flightplan and specify R for PBN with PBN/D2 in field 18. Also, RNAV(GPS) approaches only require the flightplan to have G specified as ATC doesn’t know or care which set of the minimums the aircraft is equipped to fly. If the pilot requests an RNAV approach, they will get cleared for it.
