Help & Advice on an avionics upgrade path

[Ernie Martin]

I’m on my 3rd 337 (69D, 73G, 77G) and have been happy with the factory autopilot (if not working well there are still shops that fix them and can do it with just the units, off the aircraft). If field approval is an issue, it’s something to consider, plus it will save you money. In my current aircraft I have a Garmin GTN650 (touch) and a GTX335 ADS-B along with my Cessna autopilot, so some new and some old. The autopilot has served me well on several very long trips, including one from Miami to Idaho, almost at the other extreme of the country. Perhaps others might jump in here and share views on this, especially if they disagree.

Ernie

[JimC]

Instead of the GFC700, get an STEC55x and a GAD43e. Those will be STC'ed. I think it'll get you 90% of what you want.

[n86121]

Looking at the options, it would be $25k++ ish to put in a new autopilot.

The airplane is soooooo stable I hardly use it at all, but...

I took out the servos (wing panels), the brain (over rear most seats), and control head (by knee), wire tied their airframe connectors so they couldn't hang anything up, and sent to autopilots central to bench debug the whole thing.

About $5k. Works like new.

Pretty much the only thing I ever use it for is straight and level, with bearing and altitude hold. Mostly just to play with it.

Simply tweak heading knob until the projected 50mi track vector on my GPS overlies the next place I want to be, and presto.

[chrisb]

Originally Posted by JimC

Instead of the GFC700, get an STEC55x and a GAD43e. Those will be STC'ed. I think it'll get you 90% of what you want.

Yeah I think this is probably going to be the only way to go unless Dynon suddenly decide to help us.

[Dan schultz]

Using an original 400A autopilot I believe is not authorized with the Garmin WAAS navigators for LPV approaches. My understanding is the 400B is approved for LPV.

Dan

[hayesjaj]

Originally Posted by Dan schultz

Using an original 400A autopilot I believe is not authorized with the Garmin WAAS navigators for LPV approaches. My understanding is the 400B is approved for LPV.

Dan

Source for this? First I have heard of it.

[Dan schultz]

The 400A can be used for LNAV minimums, however, LPV minimums, are not authorized. Attached is a page out of the 530W installation manual rev E.

Dan

[hayesjaj]

Originally Posted by Dan schultz

The 400A can be used for LNAV minimums, however, LPV minimums, are not authorized. Attached is a page out of the 530W installation manual rev E.

Dan

Interesting! I have Rev K of same manual and it does not have that limitation. Nor does it have most of the autopilot interconnect diagrams.