Enough time has passed that no institutional memory remains at Porsche from the Mooney partnership.

The Collins autopilot and operation on Avanti II is rock solid.
I remember being blown away during my first flight when climbing 2,000 fpm just 400 feet from level of altitude. Absolutely perfect level off at exact altitude every time.
Approaches with autopilot are very precise.

Give me 30 hand flown approaches in 3 days and I could be almost as good.

3 hours in sim a couple weeks ago down at Flight Safety in West Palm beach.

2-3 times in sim per year definitely helps my low turbine time self feel more comfortable flying this airplane.

I can believe that. It's the analog Garmin<>Collins interface that I am less impressed with. Love the Garmin avionics. But paired with Garmin EIS and digital Autopilot it'd be way better.

Enough time has passed that no institutional memory remains at Porsche from the Mooney partnership.

In the interest of knowledge sharing, I thought I'd post my latest annual inspection cost, fresh from the shop.

The annual inspection cost is a common question I get when people first see it, well, actually first, I get comments about it being a catfish or sounding like a chainsaw....but then they ask about cost.

This year had the least amount of surprises. It's a little bit higher than a straight annual, as I had some 24-month items, but overall, it's a pretty clean inspection.

Matt, appreciate you sharing. Any other major shop visits you'd make in a year?






I made the post below on the Avanti 1 G600 TXi being RVSM certified in the TBM step up thread. I realize this is a better place for it



Have any Avanti I owners made a call to AeroMech? Might be worth the chat.

Showing my stupidity here: wouldn't using the delta between Collins and Garmin altimeters allow you to create your own SSEC curve?

Conduct a test like an ASE trial (high/low, fast/slow, heavy/light) and get a blended number. Garmin probably needs an endorsement from someone authoritative.

Terry, do you do work on projects like this?

Have any Avanti I owners made a call to AeroMech? Might be worth the chat.

Showing my stupidity here: wouldn't using the delta between Collins and Garmin altimeters allow you to create your own SSEC curve?

Conduct a test like an ASE trial (high/low, fast/slow, heavy/light) and get a blended number. Garmin probably needs an endorsement from someone authoritative.

Terry, do you do work on projects like this?

With zero knowledge of how RVSM certification works, I think it is more about the STC holder having the data.

And I'm not sure anyone that has been interested in the Garmin conversion of a Piaggio 1, didn't do it because of it. It would be nice to have it, but it's not a deal breaker so spending more engineering dollars might be hard for the bean counters.

What order of magnitude amount of money are we talking about? What level of commitment of a test aircraft?

Worth noting is the P180 is RVSM approved but the current Garmin conversion keeps the Colins ADC to feed the autopilot. So it would be about getting rid of the Collins ADC and feeding the a/p with the G600txi.

So, how does that actually work?

The Garmin EFIS panels have their own ADC box, GDC 7400. Outputs data on ARINC 429 busses that gets displayed on the EFIS panel.

If the Collins ADC is the only one with SSEC data, how does the correct altitude get displayed on the EFIS altitude tape if the Garmin ADC has no SSEC at all? You must have valid altitude displayed on the EFIS and you must have valid altitude for the autopilot. How is that done?

Does the Collins replace the Garmin GDC 7400 for air data on the EFIS panels? I would find that surprising if so.

Mike C.

The Airspeed, Altitude, and Vertical Speed indicators are still in the panel. As is the altitude preselect that feeds the autopilot. They remain the legally primary instruments. So the analog altimeter at FL380 is dead on, but the G600 might indicate 38120 or something.

They match pretty well at lower altitudes.

Other minor thing of note is the bugs on all the instruments still affect the autopilot - so IAS hold mode looks at the airspeed bug on the analog instrument.

I would definitely prefer to get rid of the analog stuff.

The STC allows the G600 to display the wrong altitude because it lacks SSEC?

I'm surprised this was certified. It seems disingenuous to call the G600 a "backup" instrument.

In my case, the G700 TXi panels (same as G600 TXi) display SSEC corrected altitude provided by the GDC 7400 ADC units. My GI 275 backup instrument displays uncorrected altitude. But it is a backup instrument, not the big primary display.

If I had gotten the SAM standby instrument, it does allow loading an SSEC so it would match the G700 TXi. But the GI 275 is the better choice.

Further, my Garmin ADC digital output is converted to analog signals by a converter box, so my analog autopilot actually runs on the exact same ADC data as my panels do. My original Honeywell ADC that came with the autopilot is removed.


I concur.

When/if I can get a digital autopilot, being able to remove my analog autopilot will save me 100-150 lbs and allow the removal of 13 boxes, which includes the entire AC power system.

Mike C.

What order of magnitude amount of money are we talking about? What level of commitment of a test aircraft?

Worth noting is the P180 is RVSM approved but the current Garmin conversion keeps the Colins ADC to feed the autopilot. So it would be about getting rid of the Collins ADC and feeding the a/p with the G600txi.

That’s what I expect will happen - GFC600 required, done by IJSC.

My last update from IJSC is that they are working with Garmin on it "daily" with a target of 2024. Once Garmin delivers EIS & autopilot for Piaggio, you will also be able to retrofit ANY Piaggio, not just the I's, because you will have a full avionics and autopilot suite and can remove all the Proline21 gear. The reason you can't do a II now is that Garmin and Proline21 can't interoperate in the partial solution that works in the I.