check out the approved IFR installation configurations of G5 in their STC manual page 44.
http://static.garmin.com/pumac/190-01112-10_19.pdf
If your installation satisfies this, there is no additional requirement to do any IFR paperwork for removing vacuum pump.
The only requirement would be that you retest the pitot/static system for leaks according to IFR tolerances, after the installation.
that’s because you’ll have to work on the pitot/static lines during the installation.
As stated by By9468840, the STC should cover it all… and don’t forget to order that vacuum pump pad cover and gasket 
The question is: Do you really want to get rid of vaccum? It makes a great backup and it’s “free” as it is already in. I’d simply move the vaccum attitude indicator somewhere adjacent to the G5’s so you get a great backup if you need it. Or put it in the right hand panel so the FI also has a little attitude left in front of him.
Mooney_Driver wrote:
The question is: Do you really want to get rid of vaccum?
Yes. Get rid of that junk. It’s unreliable and another unnecessary failure point. You also (depending an a/c) gain 10-20 (or more) lbs payload. I’ve been through exactly that kind of install a couple of years ago in one of our club airplanes (C182) and the takeaways are:
After install:
don’t worry about redundancy; the units have an internal 4-hour battery and you likely run out of gas (or bladder….) before that
I’m very fond of the G5 but I believe a dual G5 setup (thus both units interchangeably acting as backup AIs) is connected via some sort of „can bus“ and I read on here before that some weird software corruption caused both units to crap out. The same goes for the GI275.
The notion to get rid of vacuum instruments + all the accessory „garbage“ is very trendy right now. I’d like to know: how common are vacuum failures really? And apart from being vacuum powered, are there any other drawbacks of going to fully digital (software derived) instruments vs. mechanical ones?
You also (depending an a/c) gain 10-20 (or more) lbs payload
Impossible to gain so much. Especially if the autopilot needs another pitch/roll source; the GI275 weighs 1.1kg and the KI256 weighs 1.5kg. I know exactly the parts involved in my TB20 and they might come to 2-3kg total, net gain, in removal.
be prepared for some extended snagging. There are little gotchas in the interface with, e.g. the GNS430W.
Lots 
the units have an internal 4-hour battery and you likely run out of gas (or bladder….) before that
But you might not. The spec says “up to 4hrs” so probably 2-3hrs. If you’ve had a fallback to the G5 battery, you cannot continue a long flight, and really should do a landing ASAP as a precaution. Then you end up far from home, with a plane which can’t be flown and can’t be fixed. In Europe, things are much harder than in the US. Of course it depends on what went wrong… But a vac pump can be changed easily. You can carry a spare, easily, with the two funny shape spanners.
Vac pumps rarely just fail. I change mine when the vacuum gauge drops out of green at standard ground idle (1200rpm). I’ve replaced 3-4 of them in 20 years, and carry a spare one. They weigh maybe 0.5kg.
I would not do this just to rip out the vacuum system. You are replacing a mechanical system which has a simple failure mechanism and which any spanner monkey can fix, with an electronic system which nobody understands, whose installers just follow drawings with little idea of why and where and what, and which has hundreds of failure mechanisms including software bugs. I’ve been in electronics for nearly 60 years, and doing microprocessor based hardware and software design since the 1970s, and I can tell you the stuff is great fun but it is no magic.
Remember a GFC500 needs GPS to fly an ILS.
If I was spending money on my plane I would put it where it will give me a tangible benefit. One of these might be removing or relocating a vac pump to enable the installation of one of the little B&C backup alternators.
Peter wrote:
Impossible to gain so much
If I can still find the pic of the junk that came out of our C182 I’ll post it.
Ditch all that obsolete junk, and welcome to modernity
The result? More engine power, increased reliability, less weight, cheaper, what more?
If going dual G5 with back-up batteries, you’ll have a back-up to the back-up, how many more does one need
I’ve heard of and experienced first hand quite a few vacuum pump and instrument failures. Up to now NIL for the G5. The worst that can happen, as described above, is total elec fail = batteries take over… If playing airliner go land some place, within the next hour to be sure. Shouldn’t be a problem over Europe, should it? If VFR, which is by far the majority of SEP hours flown over Europe, you can even take all your time.
As far as carrying a unit as spare, be my guest and take one along. It will, in any case, only be a fraction of the weight of a vacuum pump
an electronic system which nobody understands
There’s nothing to “understand” in the G5 itself… A + and a – for power, a static and a dynamic line, and a data (CAN) connection.
Yes, I’m a fan of the G5. It’s a miniature replica of the PFD/ND as found on the A320 series I was privileged to fly behind for the last 10 years (8K+) spent on the line. Just watching those trend vectors move bring a smile to my face
Disclaimer: I’m in no way associated with nor sponsored by Garmin Ltd., nor any of its subsidiaries.
I am not doubting that, but the most likely reason is that the “jurassic” hardware is “minimally maintained” and stuff gets fixed only when it falls off during flight, and enough stuff has fallen off to affect the w&b, and generates complaints from the general public who don’t like cylinders and such like falling through their roof
Much of the GA scene reminds me of (when I was on motorbikes, 1975-1982) reading a review of a Harley-Davidson, freshly imported to the UK. The reviewer (Bike magazine) rode it up the M1 and documented which parts fell off at which distance, due to being shaken and vibrated. By the time he reached the northern end, all four footrests and both mirrors had fallen off, IIRC. The rider also had no fingers left. It was built for cafe cruising…
Two identical threads merged
