We are considering to install two Garmin G5 in our Piper PA28 and have therefore no use of our vacuum system. How can we legally remove the vacuum system?
Do we need an STC with new pages for the POH?
The installation manual for the G5 states that the vacuum system can be removed but does that really mean that it is approved to do so?
Would love to hear your thoughts on this.
Yes, the STC allows replacement of the old instrument with the G5 to act as primary and thus removing the vacuum system is possible.
The shop carrying out the install should provide you with an AFMSupplement for the G5 (for the POH).
Sounds good! The AFMS is available on their website but it is not obvious what can be done with the vacuum system from reading it.
Hi Niklas,
We've done that modification in 20 PA28's (installing G5, removing vacuum system) however, we did develop our own SB based on the STC and other approved maintenance data, as the specific configuration of the aircraft needs to be considered. The shop that is doing your mod needs to document (and justify based on approved data) properly what they are doing. E.g. I remember the instructions to remove the vacuum system were found on the Cadet's AMM, not the Warrior's. We were audited on it, both as a CAMO (SB) and a Part 145, and had no findings opened by the national authority. If you need some help, let me know.
Regards
Take care if you have an old AP in your PA28 - i am not quite sure if you would'nt loose it by using G5 as primaries! As far as i know only the GI275 can be connected to the older AP so that at least a combination G5/GI275 could be needed. In case you have an original Piper AP in your AC, i'd strongly recommend to ask your seller/provider "expressis verbis" whether compatible or not!
Correct. The older Piper Autocontrols are Century Autopilots and are actually rate based on the vac driven attitude indicator. A GI275 will work. A G5 will not.
[~13316] Thanks for confirming - hope it was in time for a threadopeners decision!
We will probably remove the KAP100 Autopilot that we have now. In a year or so we will hopefully put in a new Garmin autopilot.
(edit): "expressis verbis should mean before charging him to do the exchange take care with the contract - not all companies charge with this change of avionics tell the clients probable consequences or disadvantages related to the switch from vacuum to G5!
I would also be wary about relying on two identical boxes, with identical software versions, for the same function, especially such an important function as the AI. There have in the past been software issues with the G5s causing them to show a bank to one side although the wings were level. Software is supposed to work in a deterministic way, so two identical pieces of code getting the same input should produce the same result.
Therefore I would prefer having one GI275 and one G5 rather than 2 G5.
I agree. Except (correct me if I'm wrong) I believe the GI275 and G5 will be can-bus interconnected which poses another threat?!
I'd Install dual G5 (HSI/AI) via the STC, "move" the vac driven AI to the side of the panel and then use CS-SC401c to exchange the vac driven AI with this https://uavionix.com/products/av-20s/
Feasible?
Would an option be to just upgrade the software in one at a time? Or at least run it for some hours before doing both.
Thanks a lot for your inputs. We have now received most of the parts and will continue to prepare the paperwork and the "surgery". :)
The reference to the AFMS was separate to the VAC removal. I noticed that many owners do not have AFMS for installed equipment in their POH/AFM.
Have the shop tailor the AFMS for your specific install if required (part numbers / STC / serial numbers).
Wilco