I’m trying to learn as much about the regulations as I can. On a 1948 aircraft.... what gauges or avionics have to be TSO. TSO came after 1948. What about experimental glass panels in the dash? Etc. I’m so confused trying to read through the regs on CAR3 vs TSO.

I once knew a fair bit about TSO requirements in CAR4a and earlier planes. I had a few conversations with the friendly FSDO folks about it. Unfortunately I purged most of that info from my brain. What I do recall is one FDSO guy said radios on these early planes didn’t need to be tso but if the panel had to be cut to install it and the mechinc found that to be a major alteration then a field approval was going to be required and would likely be denied if the radio did not have a tso.

Regardless of what the regs say what really matters is what your IA is willing to sign off on each annual.

For example: A guy had a non-tso com radio installed in his early Cessna and flew it that way for several years. When he sold the plane the mechanic that performed the next annual found the plane unairworthy due to the radio and required that it be replaced.

Think of the TSO as giving the "possibility" of being installed in a certified airplane, not the "ability" of being installed. The ability comes down to "basis," or approval. This is what an STC is all about. The Garmin 430 for an example has an AML (approved model list) whereby any airplane on that list falls under the STC. If the airplane is not on the AML, than you can either get a field approval, or in some cases, some IA's just sign it off.

Some TSO'd items have an STC, but that STC covers only one aircraft. The Beechcraft King Air for example. It was expected that IAs would use that STC as a guideline to get a field approval for a specific aircraft other than the original one used for the STC. Just because the unit was TSO'd and had an STC didnt mean it could be installed in a bird not on the AML.

In some cases the "TSO" is a bit of BS. Some companies sell certified/TSO'd units alongside experimental units. They are the exact same units and come from the same production lines... one just happens to be more $$.

The FAA also has some rulings on what they call Non Required Safety Enhancing Equipment that you could just install...
https://rgl.faa.gov/Regulatory_and_Guid ... 8-1602.pdf
https://www.faa.gov/aircraft/air_cert/d ... ls/norsee/

The rules are pretty black and white with no room for debate... that is until the internet, different IA's, or pragmatic thinking gets tossed into the mix. I think what your talking about is the notion that just because the airplane didnt have the rules of today nor had complex requirements to fly, cant new stuff just be installed?

I think Hotrod (back in the day) installed a G5 in his early 180 using this notion. He asked an FAA inspector and they said that was fine, but I am not sure that the inspector signed a field approval, so who knows what the next opinion might say... During a pre-buy some IA might say that the installation isn't legal and then tells the customer they wont be able to annual it. Right or wrong, and without the FA or STC paperwork, that IAs opinion is just as valid as the one that signed off the install in the first place.

In the end, it all comes down to if it gets signed off or not, and then as Whee mentioned, if the next guy thinks the installation was bollocks or not. IMHO, the best route is always the simplest route, which is to install an officially approved unit with by field approval or STC and be done.

So much good stuff is available now that comes with paperwork.

Bigrenna wrote:Think of the TSO as giving the "possibility" of being installed in a certified airplane, not the "ability" of being installed. The ability comes down to "basis," or approval. This is what an STC is all about. The Garmin 430 for an example has an AML (approved model list) whereby any airplane on that list falls under the STC. If the airplane is not on the AML, than you can either get a field approval, or in some cases, some IA's just sign it off.

Some TSO'd items have an STC, but that STC covers only one aircraft. The Beechcraft King Air for example. It was expected that IAs would use that STC as a guideline to get a field approval for a specific aircraft other than the original one used for the STC. Just because the unit was TSO'd and had an STC didnt mean it could be installed in a bird not on the AML.

In some cases the "TSO" is a bit of BS. Some companies sell certified/TSO'd units alongside experimental units. They are the exact same units and come from the same production lines... one just happens to be more $$.

The FAA also has some rulings on what they call Non Required Safety Enhancing Equipment that you could just install...
https://rgl.faa.gov/Regulatory_and_Guid ... 8-1602.pdf
https://www.faa.gov/aircraft/air_cert/d ... ls/norsee/

The rules are pretty black and white with no room for debate... that is until the internet, different IA's, or pragmatic thinking gets tossed into the mix. I think what your talking about is the notion that just because the airplane didnt have the rules of today nor had complex requirements to fly, cant new stuff just be installed?

I think Hotrod (back in the day) installed a G5 in his early 180 using this notion. He asked an FAA inspector and they said that was fine, but I am not sure that the inspector signed a field approval, so who knows what the next opinion might say... During a pre-buy some IA might say that the installation isn't legal and then tells the customer they wont be able to annual it. Right or wrong, and without the FA or STC paperwork, that IAs opinion is just as valid as the one that signed off the install in the first place.

In the end, it all comes down to if it gets signed off or not, and then as Whee mentioned, if the next guy thinks the installation was bollocks or not. IMHO, the best route is always the simplest route, which is to install an officially approved unit with by field approval or STC and be done.

So much good stuff is available now that comes with paperwork.

What he ^^^ said. You can find any answer you want via the internet, but the bottom line is, at some point, unless it's covered in legal paperwork, it may not fly....literally. Age and what certification rule the airplane was produced under makes no difference.

MTV

All airplanes for sale should come with a California Proposition 65 style warning: "caution, in some universe or legal interpretation, something that may or may not have been done to this aircraft in its past 70 year history may at any point in the future be considered no longer legal"

TSO's & STC AML's are IMHO a very gray area.
For example, the uAvionix Tailbeacon has an STC which incorporates an AML.
But uAvionix tells you to do a 337, and have your IA sign it off--
even if your model airplane is not included on the AML.
So it's kinda like an STC, and kinda not.

Years ago, I wanted to replace the com radio in my airplane.
My IA buddy talked to his PMI, who was himself an IA with lots of airline, air taxi, & part 91 GA experience.
The PMI told my buddy that if the radio was TSO'd, the IA could sign it off- on a 337, as a major alteration I suppose.
But if it wasn't TSO'd, it would require a field approval.
I wanted to install an Icom A200, & it so happened that they had a TSO'd version,
as well as a non-TSO'd version-- the TSO'd one was $100 more.
I figured $100 was pretty cheap to avoid a bunch field approval BS, so it was a no-brainer.

Now I've heard that for IFR use, radio gear needed to be TSO'd,
but that was the first time I'd ever heard what he said about field approvals.
Also, I've owned airplanes in which radio's had been installed & just signed off with a logbook entry,
presumably as a minor alteration, without a 337 being done.

Nothing is a problem until it's a problem but you wont know it's a problem until someone with more certifications than you says it's a problem.
Other than that, it's not a problem.

hotrod180 wrote:TSO's & STC AML's are IMHO a very gray area.
For example, the uAvionix Tailbeacon has an STC which incorporates an AML.
But uAvionix tells you to do a 337, and have your IA sign it off--
even if your model airplane is not included on the AML.
So it's kinda like an STC, and kinda not.

Years ago, I wanted to replace the com radio in my airplane.
My IA buddy talked to his PMI, who was himself an IA with lots of airline, air taxi, & part 91 GA experience.
The PMI told my buddy that if the radio was TSO'd, the IA could sign it off- on a 337, as a major alteration I suppose.
But if it wasn't TSO'd, it would require a field approval.
I wanted to install an Icom A200, & it so happened that they had a TSO'd version,
as well as a non-TSO'd version-- the TSO'd one was $100 more.
I figured $100 was pretty cheap to avoid a bunch field approval BS, so it was a no-brainer.

Now I've heard that for IFR use, radio gear needed to be TSO'd,
but that was the first time I'd ever heard what he said about field approvals.
Also, I've owned airplanes in which radio's had been installed & just signed off with a logbook entry,
presumably as a minor alteration, without a 337 being done.

uAvionix gets away with that because the FAA has a ruling that ADSB don't need field approvals, if it's certified for one aircraft it's certified for all.

My understanding that a comm radio install is a minor alteration unless you have to cut a new hole in the panel.

Bottom line is, as stated above, the internet definitely muddies the waters with opinions.

Bigrenna wrote:...I think Hotrod (back in the day) installed a G5 in his early 180 using this notion. He asked an FAA inspector and they said that was fine, but I am not sure that the inspector signed a field approval, so who knows what the next opinion might say... During a pre-buy some IA might say that the installation isn't legal and then tells the customer they wont be able to annual it. Right or wrong, and without the FA or STC paperwork, that IAs opinion is just as valid as the one that signed off the install in the first place.....

That was back in 2016.
I emailed the local FSDO, "attn airworthiness dept", & one of their inspectors told me that yes,
CAR 3 aircraft didn't require TSO'd instruments:
"just make sure that all work is completed by a licensed mechanic & that you make a logbook entry showing the work performed".
My IA wanted to confirm this with his PMI, but instead that inspector OK'd the installation
by quoting the requirements chapter & verse right out of the FAA policy statement for "replacement of vacuum driven attitude indicators"

http://rgl.faa.gov/Regulatory_and_Guida ... -23-08.pdf

That was fine by me. I did have to buy a $150 backup battery that I didn't really want to buy--
but I figured that was a cheap price to pay for a quick & easy legit installation.
We did the work, and referenced the policy statement in the logbook entry--
no 337 required, as the PS says it's a minor alteration.
I did keep hard copies of all the correspondence with the 2 FAA inspectors,
as well as a hard copy of the policy statement.

Seems well defined by the Policy Statement. I don't see how anyone could argue with that.

I have a Stinson 108-1 that I'm restoring from the ground up. I have to completely rebuild the dash anyway so I want modern glass instruments.

I think its CRAZY that I have to pay $6100 MORE for the "Certified" version of the Garmin 3X touch over the Experimental which we all know are the exact same equipment.

You KNOW the Experimental version is still FAR exceeding the CAR3 3.663 requirements.

^ and that there is why I'm building a plane

I've seen some very nice "for experimentals" engine monitors that are way less $ than certified.
I'd like to install one for oil temp, oil pressure, and multi-point CHT/EGT.
Some people here & elsewhere have told me that's legal,
as long as it's in addition to the required instruments-- not in place of them.
I ran that by my IA, & his opinion is that it needs to be at least TSO'd, if not also STC'd for my airplane..
This falls into that gray area I mentioned earlier--
maybe he's right, maybe he's wrong, but I think a lot of today's FAA inspectors would take the same position.

The short answer is no, you can't use experimental avionics in certified aircraft. There IS NO such thing as experimental avionics. And for part 91, the only things that have to MEET (not BE) TSO'd are the transponder and altitude encoder (and ADSB-Out). MEET, not BE

See This great explanatory article written by VAL AVIONICS https://www.valavionics.com/installation-in-type-certificated-aircraft.html

whee wrote:.....Regardless of what the regs say what really matters is what your IA is willing to sign off on each annual.
For example: A guy had a non-tso com radio installed in his early Cessna and flew it that way for several years. When he sold the plane the mechanic that performed the next annual found the plane unairworthy due to the radio and required that it be replaced.

Key.
Regs and / or my interpretation (or yours, or Joe Blow's) of the regs are one thing.
But if your IA refuses to buy into your rationale, you're SOL.
"Find another IA" is not always good or practical advice,
even IF you can find one who agrees with that rationale.
And I suspect a lot of FAA inspectors would also take the conservative point of view.
Is it really worth the hassle if one decides to ground your airplane,
even if you can (eventually) prove your case?

This really is a crock of horseshit.

If the airplane had all the required equipment per its MEL or TC or STC or whatever, anything additional that the owner wants installed in the panel should be fair game.

Instead we have all these BS “work arounds” with suction cup mounts or Velcro so that Joe Pilot can mount a kitchen timer to help with fuel management.

Hell, stick a toaster in the dash for all the regulations care. It’s the “opinions” and “conservative approach” that’s making GA unaffordable and unappealing to the younger generations. A Cessna 180 is not a 737; they cannot be treated the same with regard to paperwork.

The road to hell is paved with good intentions. To make someone go through a bureaucratic nightmare just to augment the factory engine gauges is the wrong answer. Instead of putting the burden on the owner to “find a new IA,” we (the FAA) needs to re-educate ALL IAs/A&Ps that touch GA aircraft.

Put an EDM 350 in your dash, and leave the original Cessna CHT/EGT gauges in place. I’d challenge anyone to justify that aircraft non-airworthy based on its TC.

Or just buy/build an E-AB and welcome the common sense that thankfully still exists in that sector of GA.

Every IA I know locally is find with anything non-TSO as long as it's not counting as your primary required instrument. My plane doesn't have gyros to start with, so adding experimental G5's for example is no issue. Non-TSO Garmin GTR200, no issue. However, I would need a TSO unit to replace airspeed, altimeter, oil pressure, etc.

So, why can't I install two of those experimental Aerovonics solid state gyros (AI and DG) as they don't have their STC yet , but the experimental and certified versions are identical, sans piece of paper (and the experimental version is much cheaper). I believe for the early 180s the vacuum system/gyros were an option.

C180_guy wrote:So, why can't I install two of those experimental Aerovonics solid state gyros (AI and DG) as they don't have their STC yet , but the experimental and certified versions are identical, sans piece of paper (and the experimental version is much cheaper). I believe for the early 180s the vacuum system/gyros were an option.

Who is telling you that you can't?

C180_guy wrote:So, why can't I install two of those experimental Aerovonics solid state gyros (AI and DG) as they don't have their STC yet , but the experimental and certified versions are identical, sans piece of paper (and the experimental version is much cheaper). I believe for the early 180s the vacuum system/gyros were an option.

That was my approach installing the G5 (pre-STC) into my C180.
One FAA inspector told me via email it was fine.
Another, the PMI for my area, told my IA it was fine, "as long as you.....",
and went on to quote chapter & verse out of FAA policy statement PS-ACE-23-08.
https://www.kellymfg.com/images/PS-ACE-23-08.pdf
So his take on it differed from the first inspector.