I think there is a lot of instrument maintenance firms here in Europe who do just the minimum required to make the instrument work. Hence you get an “overhauled” vac AI failing again say a year later because a different part of it has worn out.
If I wanted a full rebuild I would send it to Castleberry Instruments in Texas, but that will cost you more than the UK firm I have used a few times (my post #23 above) and which takes a good number of months plus needs a ton of chasing to get the job finished.
Yes exactly an electric backup needs to be totally independent. Imagine a lightning strike takes out your whole panel… in IMC. You will die if that happens because one cannot fly in IMC without a gyro (except in the most smooth conditions, when it is possible with a compass and a lot of previous practice).
I contacted #23 (again) and also Castleburry.
I’m really disappointed with the situation.
Jacko is right, I’m complaining after all 
PCV, a little more seriously than my previous suggestion, perhaps it’s time for some lateral thinking.
Perhaps it is worth trying to separate
1. The instruments required by your state of registry;
from
2. The instruments which you would like to keep you safe.
You must comply with 1. but those requirements will always lag behind what is available for 2.
As I understand it, 1. requires that you must have a vacuum AI, as a backup to a (much more reliable) G1000. So it’s pretty unlikely that you will ever need the backup, and even less likely that it’ll choose that unfortunate moment to go tits-up.
If you add under 2. a self-contained non-certified gizmo like a Dynon D2, switch it on before entering IMC, and practice using it from time to time, then you have covered the remote chance that all of the instruments required by your state of registry will gang up to kill you at the same time.
P.S. Compared with a new G5 installation, this solution should save some cash which you can invest in AVGAS, or squander on food, home and furniture. 
Jacko
You’re right.
Hence my interest in ADL200, which incorporate uncertified AHRS.
But, I must struggle to get the descent AI work at least properly. I can’t understand why I don’t manage to get such a basic instrument to work.
As for cash I would save, you had suggested some time ago, i keep it for Mrs PCV
Jacko wrote:
As I understand it, 1. requires that you must have a vacuum AI, as a backup to a (much more reliable) G1000. So it’s pretty unlikely that you will ever need the backup, and even less likely that it’ll choose that unfortunate moment to go tits-up.
My understanding is that you must have a backup with a separate power source. It doesn’t necessarily have to be a vacuum AI.
Yes that’s correct. We have quite a lot of threads here, especially with posts by NCYankee describing the options.
However some battery backed instruments don’t have a big enough battery for this purpose.
So I am hopeless this way.
Not going to install a second alternator for that purpose :-)
I will struggle to have the vacuum one work (no reason we don’t reach that) and maybe find a neat AHRS based solution as a convenient add on.
Will keep you tuned !
Having independent systems of alternator driven electronic systems and vacuum driven mechanical is good practice for failure scenario risk management. get it repaired.
liftvectorup wrote:
get it repaired.
I will.
PS: but it would be of great help if seo familiar with those instruments, could tell if the problem likely comes from the AI itself, or the vacuum system (pump, regulator or tubing).
I would still recommend getting it repaired/serviced by a competent shop, air driven gyros are not nuclear rocket science.
If they test it first on the bench, they can tell you if the instrument if faulty or not.
