sdflysurf Posted April 25, 2020 Author Report Share Posted April 25, 2020 Avionics is happening today finally! I have a few urgent questions for the group and how I would find out if it is allowed / STC / approved / legal / possible / etc! 1) Vacuum Low and High Indicator lights - I am removing the DG and replacing it with an HSI, so while I was removing the DG I found a vaccum switch that powered the Low and High Indicators on the Pilot side panel. I have a suction gauge on my right side panel - CAN I REMOVE THE VAC LOW AND HIGH LIGHTS or do they need to stay somehow!?? 2) EGT and CHT - Can I eliminate the old EGT that came above the yoke on my old panel and use the JPI? Similarly there is a CHT in the instrument cluster, what must I do for that? I would really like to just put all EGT and CHT for all 4 cylinders on the JPI EDM 700 but I don't think it is certified primary instrument. (?) 3) I have the cool retro boomerang looking antennas - the Avionics guy said the coat is coming off on one, is there a special white paint I could use or do I need to have it professionally overhauled. The avionics guy said there was a nice WAAS-GPS/COM combo antenna I could get, anyone heard of that? Otherwise I'd like to keep the cool boomerang antennas they look cool! Quote Link to comment Share on other sites More sharing options...
Paul_Havelka Posted April 25, 2020 Report Share Posted April 25, 2020 1 hour ago, sdflysurf said: Avionics is happening today finally! I have a few urgent questions for the group and how I would find out if it is allowed / STC / approved / legal / possible / etc! 1) Vacuum Low and High Indicator lights - I am removing the DG and replacing it with an HSI, so while I was removing the DG I found a vaccum switch that powered the Low and High Indicators on the Pilot side panel. I have a suction gauge on my right side panel - CAN I REMOVE THE VAC LOW AND HIGH LIGHTS or do they need to stay somehow!?? I'm pretty sure that you will need to keep the lights. 2) EGT and CHT - Can I eliminate the old EGT that came above the yoke on my old panel and use the JPI? Similarly there is a CHT in the instrument cluster, what must I do for that? I would really like to just put all EGT and CHT for all 4 cylinders on the JPI EDM 700 but I don't think it is certified primary instrument. (?) Check the required equipment in your POH and if it's not listed then you should be able to remove the original egt gauge and use the EDM. 3) I have the cool retro boomerang looking antennas - the Avionics guy said the coat is coming off on one, is there a special white paint I could use or do I need to have it professionally overhauled. The avionics guy said there was a nice WAAS-GPS/COM combo antenna I could get, anyone heard of that? Otherwise I'd like to keep the cool boomerang antennas they look cool! These are just my thoughts not that of an A&P 1 Quote Link to comment Share on other sites More sharing options...
carusoam Posted April 25, 2020 Report Share Posted April 25, 2020 The POH lists the MELs... VFR, IFR, day, night.... 1) High low vac are important warning lights for IFR flight... too easy to follow an errant AI as the vac slowly wanes.... 2) The old EGT gauge is not on the MEL... it doesn’t even have numbers on it in some cases... the single CHT is... 3) Doing away with instruments on the MEL are ‘primary’ replacing them with a JPI... the JPI needs to be of a ‘primary’ instrument quality... the 900 series is primary... other instruments may have some primary data mixed in with not primary data... know what you are getting as a replacement... 4) selecting the old 7 antenna is up to you... check with the used equipment guy behind the spooky mask and loud saw... he has these in good condition... painting old antennas has challenges... many white paints block out radio signals.... New antennas are light years ahead of the old ones...new cables and proper grounding are good ideas as well... PP thoughts only, not a CFI... or instruments guy... Best regards, -a- Quote Link to comment Share on other sites More sharing options...
Andy95W Posted April 26, 2020 Report Share Posted April 26, 2020 4 hours ago, sdflysurf said: 1) Vacuum Low and High Indicator lights - I am removing the DG and replacing it with an HSI, so while I was removing the DG I found a vaccum switch that powered the Low and High Indicators on the Pilot side panel. I have a suction gauge on my right side panel - CAN I REMOVE THE VAC LOW AND HIGH LIGHTS or do they need to stay somehow!?? 2) EGT and CHT - Can I eliminate the old EGT that came above the yoke on my old panel and use the JPI? Similarly there is a CHT in the instrument cluster, what must I do for that? I would really like to just put all EGT and CHT for all 4 cylinders on the JPI EDM 700 but I don't think it is certified primary instrument. (?) 3) I have the cool retro boomerang looking antennas - the Avionics guy said the coat is coming off on one, is there a special white paint I could use or do I need to have it professionally overhauled. The avionics guy said there was a nice WAAS-GPS/COM combo antenna I could get, anyone heard of that? Otherwise I'd like to keep the cool boomerang antennas they look cool! (1) Removal of the lights is going to be up to your A&P/IA. Some guys are adamant that the lights must remain because that's how the airplane was certified. Others (like me) only want to see that there is a means of monitoring the vacuum system. With that said, I would insist that the vacuum gauge be at least TSO'ed, and I would submit a 337 (not for field approval, just a paperwork submission to the FAA). (2) as stated above, you can get rid of the EGT, but the CHT must remain and be operational because the JPI 700 series is not certified as primary. (3) Antennas are a tough call. You're not supposed to paint them because most white paint has Titanium White which can degrade performance. At some point, your antenna will probably begin to break down on its own and your transmission/reception range will begin to suffer. On one airplane, I bought a roll of white plastic tape and put that on an antenna that had its coating removed over time. It lasted about 5 years. With all of the work you're doing, I think I'd consider the combined COM/WAAS antenna and you won't have to worry about it for decades. 1 Quote Link to comment Share on other sites More sharing options...
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