I too have a pair of AV-30C devices. I’ve experienced what stid2677 noted at startup, but it always erects fine as soon as level. If you move before it aligns, same thing….but no big deal, in the short time it takes to align, you SHOULD be monitoring engine parameters and getting the plane ready to taxi.
More critical in the certified world is DG precession in the instrument set up as a DG. These units really need a remote magnetometer to be reliable, at least in planes with four cylinder engines. Vibration causes precession. uAvionix has a remote magnetometer approved for the Experimental installs, but not for the Certified, yet. Working on it.
I removed my vacuum system, as well as the failed DG and the AH that was headed south, installed two AV-30C and am very pleased with them. I look forward to them getting the remote magnetometer approved for certified, but not in a big panic. I have an O-360, and even with a MT prop, balanced, those engines shake.
If I were flying a Cub, I’d definitely install ONE AV-30C, set up as an attitude instrument. My GPS and whiskey compass could serve as he “DG”….and looking it the front.
BUT, to me the HUGE benefit to the AV-30 is that it can display all kinds of very useful data, besides attitude. Like direct readout Density Altitude, true airspeed, G limits, AOA, etc, etc. And, BTW, if you install only one AV-30, it can display BOTH attitude and direction.
They are great units, and seriously, I wish I’d had ONE of these things back when I spent a lot of time churning around at 200 agl.
MTV