Can someone explain TSO'd to me

SixPapaCharlie

SixPapaCharlie

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Looking for a Fuel Flow and CHT gauge for our plane.

I see several on Chief that are way cheaper then the $8000 quote I just got to have an EDM700 installed. :yikes:

I understand TSO has something to do with what aircraft they are allowed on.

How can I determine if a gauge is allowed on my aircraft?
 
A TSO is a minimum performance standard for specified materials, parts, and appliances used on civil aircraft. When authorized to manufacture a material, part, or appliances to a TSO standard, this is referred to as TSO authorization. Receiving a TSO authorization is both design and production approval. Receiving a TSO Authorization is not an approval to install and use the article in the aircraft. It means that the article meets the specific TSO and the applicant is authorized to manufacture it. FAA approval is required to install a TSO'd part.

FAA-PMA is a method that allows qualified sources that are not the original type certificate holder to design and manufacture replacement parts for aircraft.

A supplemental type certificate (STC) is a type certificate (TC) issued when an applicant has received FAA approval to modify an aircraft from its original design. The STC, which incorporates by reference the related TC, approves not only the modification but also how that modification affects the original design.
 
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Cli4ord definitions are correct. but doesn't say much but how TSO's are applied. Even the FAA occasionally seems to have trouble with this.

For some things TSO compliant equipment is required for example transponders. This is required by FAR 91.
However there not a requirement that all equipment in certified aircraft be TSO's. For example there is no TSO for a G-Meter. But it is perfectly legal to install a G-Meter in an aircraft.
If someone insists that a peice of equipment be TSO's. 1st ask which TSO applies to it. Some equipment may meet TSO requirement, but there is no legal requirement for it to do so to be installed in a certified aircraft.
2nd ask which rule requires the equipment to meet a TSO.

Hope this helps.

Brian
 
TSO is neither necessary nor sufficient for installing something in a certified aircraft.

Though in the case of GPSes with IFR capabilities the regs specifically call out a TSO that they must have to be used in the IFR system when required.

You need an STC or PMA to install something with only some paperwork by your mechanic. (There's always the 337 route). Though there are plenty of exceptions where you don't even need any of that.

Back here in reality, even some mechanics won't install a non TSO gyro or radio. That is their prerogative even if their legal reasoning isn't very firm.
 
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SixPapaCharlie said:
I see several on Chief that are way cheaper then the $8000 quote I just got to have an EDM700 installed.
Click to expand...

That's because the units you are seeing at Spruce, even though they are the same model, do not come with an STC.
 
bartmc said:
TSO is neither necessary nor sufficient for installing something in a certified aircraft.

Though in the case of GPSes with IFR capabilities the regs specifically call out a TSO that they must have to be used in the IFR system when required.

You need an STC or PMA to install something with only some paperwork by your mechanic. (There's always the 337 route). Though there are plenty of exceptions where you don't even need any of that.

Back here in reality, even some mechanics won't install a non TSO gyro or radio. That is their prerogative even if their legal reasoning isn't very firm.
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Indeed, I'd like to know where does it say a gyro or magnetic compass has to be TSO in order to be installed in a certified aircraft? Honest question.

On the other hand, do they have to be PMA? :confused:
 
hindsight2020 said:
Indeed, I'd like to know where does it say a gyro or magnetic compass has to be TSO in order to be installed in a certified aircraft? Honest question.

On the other hand, do they have to be PMA? :confused:
Click to expand...

I'm not a reg expert, but AFAIK there isn't. In the case of radios, the Kx170B isn't TSOed. There's a whole lotta illegal planes if radios require a TSO. Pi got tempted with the falcon gyros. I couldn't find any legal reason that I couldn't install them. Someone will come around and give one. I wound up buying "good" instruments instead of the falcons.
 
So how does one find out if they can put a gauge in their plane?

How do I know what CHT I can buy and have installed legally?
What is the process for determining this?
 
SixPapaCharlie said:
So how does one find out if they can put a gauge in their plane?

How do I know what CHT I can buy and have installed legally?
What is the process for determining this?
Click to expand...

A mechanic may obtain a field approval from the FAA to modify your plane by installing a CHT. What the FAA will approve or not is up to the FAA.
 
PMA approval applies also to new components were there is no TSO definition. Like long range tanks kits or speed mods. For these an STC is first issued but to manufacture and sell them a PMA is required. Any aircraft component TSOd or STCd that is FAA approved and for manufacturing and sale need to go through the PMA approval process. The PMA is issued by an FAA MIDO office while the STC/TSO is issued by an FAA ACO office. FAA approved manufacturers get audited by FAA MIDO offices. Maintenace facilities like repair stations or MROs are audited by FAA FSDO offices.

José
 
And now we know why it costs so much to own and fly airplanes. Well, that and lawyers who would be happy to sue every manufacturer who has a part on the aircraft when it falls out of the sky.
 
TSO items a typically required when you start getting into commercial operations (121, 135 etc). Like anything else 'certified', they cost more because the manufacturer had to spend a lot of money to prove the part was acceptable to the FAA. They pass that cost on to you.

TSOs also affect more than just replacement parts. When you start getting into the big leagues, even your headset must be TSO'd.
 
A "TSO" is just a standard for a given part (which tend to be pretty dry reads because they typically just reference some other industry standard). The TSOA (TSO Approval) is a statement that the manufacturer is conforming to the standard and implicit in that approval is approval to manufacture.

PMA is approval to manufacturer a part (as stated typically one that doesn't have a TSO to follow) and doesn't rise to the level of a part like the airframe, engine or propeller that has a type certificate.

Essentially there has to be three things for a legal part:

1. The part has to be approved in it's design (Type Certificate, TSO, or compliance with some recognized standard like a MILSPEC or like LSA's some industry standard).

2. Whoever makes the part must have approval to produce the part.

3. There must be authority to put it on a particular airplane. Again the small stuff slides under general rules. Larger stuff must be done under the type certificate, an STC, or other "data acceptable to the administrator."


For most parts a TSO is hence neither necessary nor sufficient for installation in a part 91 aircraft. Exceptions include things like ELTs and IFR GPS.
 
SixPapaCharlie said:
How can I determine if a gauge is allowed on my aircraft?
Click to expand...

So the short answer to your last question -
The guages you refer to would require an STC for your specific aircraft model. The manufacturer of those guages would provide that paperwork if it exists.

If the mfg never obtained an STC, then the longer route would be to try and have your mechanic file a 337 form for approval to modify the aircraft from it's original certificate by installing these guages (or replacing existing ones if it already came with them).
 
SixPapaCharlie said:
Looking for a Fuel Flow and CHT gauge for our plane.

I see several on Chief that are way cheaper then the $8000 quote I just got to have an EDM700 installed. :yikes:

I understand TSO has something to do with what aircraft they are allowed on.

How can I determine if a gauge is allowed on my aircraft?
Click to expand...

The regulatory stuff has been covered, but from a more convenient standard by plane owners, the rule is that you want to permanently mount something in your standard type cert aircraft, it has to comply with either a TSO approval, or be a PMA standardized part, or have a STC, and your plane must be listed on the STC list.

Take a look at these links:

http://www.chiefaircraft.com/aircraft/engine-instruments/ei-engine-monitors/ei-cgr-30p-4-b.html

http://www.chiefaircraft.com/pdf/CGR-30P-STC-AML.pdf

Go to the 'specs' tab, and look at the gobbledegook there which gives; 'certifications, environmental, and performance' entries. Because this is a mutli-use instrument, it has to go several different ways. First, because your plane came with a Tach, oil pressure, and oil temp from the factory, they have to comply with the various TSO standards for those OEM type of gauges, and the TSOs are listed there.

Because your plane did not come from the factory with a 6 probe CHT and EGT gauge, that is a modification, or a Supplement to your plane and the second link is the Supplement to the original Type Certificate(STC) to use that instrument in your specific plane. Scroll through the list and find your orig TC, I think maybe item 131. That means you are allowed to follow the directions in the install kit, modify your POH, and follow the instructions for continued airworthiness, and supply the FAA with the modification info when the instrument is installed.

The form to modify a plane from it's original condition is a form 337. This describes the alteration, and the method used to perform it. For a device with an existing STC, it's pretty easy, and the verbiage will be supplied by the A&P/IA doing the work: "Instrument CGR-30P-4-B installed in this aircraft IAW the instructions in the STC SA02283SE. Tested and verified all parameters within operational limits". Or something to that effect.

Where things get funny is something called a 'field approval' for modification. Back in the bad old days, guys would want something changed on their plane, and they would get an A&P to make the modification, then fill out a 337, have the plane and paperwork inspected by the local branch FSDO of the FAA, and if it looked copacetic, the FAA would approve the change. A good example would be a ski tube in a Cessna 172A. Once a 337 for that change is 'in the system' and has had the FAA stamp of approval, it's kind of a workaround to the STC process. In fact, there are databases of 337s floating around for various airframes and mods that others can use to copy, and modify their own aircraft. Once the FAA certifies that a ski tube in a 172A is approved for SN xx-xxxx, the same mod can usually be done for similar planes, provided the modification methods, and materials and workmanship are alike.

http://www.popularaviation.com/Form337.asp

Now, reality sets in. About 30 years ago, the FAA clamped way down on these field approvals. Surely the owners and A&Ps may have abused the method, and the FAA stopped it's field approval system or at least reduced it to a minimum. However, those old 337 major repair and major alteration forms are still out there, and form the basis for a lot of common alterations(ski tube in a 172A).

In short, unless it's been done on a form 337 which was approved, you're not going to get it approved on a field basis unless it's got an STC, or you go through some pretty big hoops to get it approved, which would be the same hoops the mfg of the instrument went through to get the supplement. It's an expensive an onerous process.

My example; I had an EGT gauge in my plane that was about 20 serial numbers before the STC was issued for the gauge. It's exactly the same gauge used but the mfg of the product started the STC at a specific SN, and mine is before that. You would think that I could get a field approval for that instrument on a 337. Well, so far it doesn't look good. The FAA so far has said the remedy is to either replace it with the later SN, or get the mfg of the SN I have to be covered under the STC. Unlikely, so I'm stuck looking at my unapproved gauge, and either removing it, or labeling it 'INOP' during annual insp. OBTW, it's been in the plane for 9 years, and has passed 9 annual inspections without a squawk. Hmmmmmm
 
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docmirror said:
The regulatory stuff has been covered, but from a more convenient standard by plane owners, the rule is that you want to permanently mount something in your standard type cert aircraft, it has to comply with either a TSO approval, or be a PMA standardized part, or have a STC, and your plane must be listed on the STC list.

Take a look at these links:

http://www.chiefaircraft.com/aircraft/engine-instruments/ei-engine-monitors/ei-cgr-30p-4-b.html

http://www.chiefaircraft.com/pdf/CGR-30P-STC-AML.pdf
Click to expand...

So how did you navigate the 2nd link (pdf)?
We are actually 131 on there Socata TB9
How did you get from the instrument page to the PDF showing it is allowed on our plane?
 
SixPapaCharlie said:
So how did you navigate the 2nd link (pdf)?
We are actually 131 on there Socata TB9
How did you get from the instrument page to the PDF showing it is allowed on our plane?
Click to expand...

First link, under the 'description' tab, click the 'Download the Approved Model List Here', might be in blue text, depending on your browser settings.
 
docmirror said:
The regulatory stuff has been covered, but from a more convenient standard by plane owners, the rule is that you want to permanently mount something in your standard type cert aircraft, it has to comply with either a TSO approval, or be a PMA standardized part, or have a STC, and your plane must be listed on the STC list.
Click to expand...

So the AoA indicator, the G-meter, the avionics master, the radome protection film, and the ground comm switch installed in my airplane are all illegal?


The form to modify a plane from it's original condition is a form 337.
Click to expand...
AFaIK a 337 is not required for anything that's not a major modification.

My example; I had an EGT gauge in my plane that was about 20 serial numbers before the STC was issued for the gauge. It's exactly the same gauge used but the mfg of the product started the STC at a specific SN, and mine is before that. You would think that I could get a field approval for that instrument on a 337. Well, so far it doesn't look good. The FAA so far has said the remedy is to either replace it with the later SN, or get the mfg of the SN I have to be covered under the STC. Unlikely, so I'm stuck looking at my unapproved gauge, and either removing it, or labeling it 'INOP' during annual insp. OBTW, it's been in the plane for 9 years, and has passed 9 annual inspections without a squawk. Hmmmmmm
Click to expand...
BTW AFaIK, labeling something INOP only allows you to leave it in and non-working until the next annual, at which time it has to be repaired or removed.
 
gismo said:
So the AoA indicator, the G-meter, the avionics master, the radome protection film, and the ground comm switch installed in my airplane are all illegal?



AFaIK a 337 is not required for anything that's not a major modification.


BTW AFaIK, labeling something INOP only allows you to leave it in and non-working until the next annual, at which time it has to be repaired or removed.
Click to expand...

I didn't say anything about your plane. You should direct your question to the FAA/FSDO. I'm sure you'll get at least 58 interpretations.

Covered in the attached link which you conveniently left out of the quote.

Inop equipment which is on the type certificate, or MEL must be repaired and brought back into operating condition, usually before the next annual. In some cases, before the next flight. Even at that, the FAA may interpret the inop equipment far differently, and I will not delve into their thinking. As for my specific case, you have no knowledge of when, or if I have had an annual done with the offending instrument labelled as inop, so I don't know what your getting in my face about, unless you just want to argue.
 
docmirror said:
I didn't say anything about your plane. You should direct your question to the FAA/FSDO. I'm sure you'll get at least 58 interpretations.

Covered in the attached link which you conveniently left out of the quote.

Inop equipment which is on the type certificate, or MEL must be repaired and brought back into operating condition, usually before the next annual. In some cases, before the next flight. Even at that, the FAA may interpret the inop equipment far differently, and I will not delve into their thinking. As for my specific case, you have no knowledge of when, or if I have had an annual done with the offending instrument labelled as inop, so I don't know what your getting in my face about, unless you just want to argue.
Click to expand...
Whoa, no face getting in intended. It sounded like you were saying that anything installed required a TSO, STC, etc. and I was under the impression that this is not the case for things that do not fit the definition of a major modification (alteration). AFaIK the items I listed were installed in my airplane as such. My question was does this make them "illegal" in your opinion.

As to the link, it wasn't so much convenience but rather ignorance as I didn't open the link and didn't realize it spoke to the issue of INOPs and annual inspections. In my (admittedly weak) defense those links were a long way from the paragraph I commented on.

Oh, and I do like to argue but I prefer to call it discussion.
 
gismo said:
Oh, and I do like to argue but I prefer to call it discussion.
Click to expand...

I said what I said trying to help a fellow plane owner, not get bogged down in the minutia of 337/STC/inop equipment. He's contacted me offline for further assistance, so that's taken care of.

As for the rest - meh, give me 2 hours with any +25YO GA plane on the ramp and I'll find a questionable interpretation of the regs at work. I recall a rather nasty thread a while back about a 4 vs 6 ply rating on a GA tire.

whatev.
 
This is a very good discussion even though this thread has been dormant for a while.

I'm having to build a new panel from scratch due to a ground up rebuild and the gauges in the panel were from 1946 in a Stinson 108. This aircraft was and still is a CAR3 certified aircraft. If I look at the TCDS, it refers me to CAR3 section 3.663 which simply outlines a list of required instruments, Altimeter, Airspeed, Magnetic compass, oil temp, oil pressure and a Tach. No mention of TSO (because that term came AFTER CAR3).
So now I'm trying to find instruments to rebuild with and I'm being told they HAVE to be TSO to be installed in a certificated aircraft. Well the TCDS nor CAR3 call out that requirement.
 
Will Ware said:
This is a very good discussion even though this thread has been dormant for a while.

I'm having to build a new panel from scratch due to a ground up rebuild and the gauges in the panel were from 1946 in a Stinson 108. This aircraft was and still is a CAR3 certified aircraft. If I look at the TCDS, it refers me to CAR3 section 3.663 which simply outlines a list of required instruments, Altimeter, Airspeed, Magnetic compass, oil temp, oil pressure and a Tach. No mention of TSO (because that term came AFTER CAR3).
So now I'm trying to find instruments to rebuild with and I'm being told they HAVE to be TSO to be installed in a certificated aircraft. Well the TCDS nor CAR3 call out that requirement.
Click to expand...

A lot of folks will tell you that a TSO isn't required (and they're probably right), but the only opinion that truly matters is that of the guy who is signing off on the install. If the guy (or gal) signing off the installation insists on TSO, either buy TSO'd stuff or find a new installer.
 
Will Ware said:
Well the TCDS nor CAR3 call out that requirement.
Click to expand...
And they wouldn’t as that is not the purpose of the TCDS/CAR3. Not really enough info to make a specific comment, but here are a few general ones.

Parts installation on a TC’d aircraft falls under one of two categories: maintenance or alteration. Parts installed as a maintenance function must be considered “acceptable” parts which are parts that generally fall under the requirements listed in 21.9, i.e., a TSO, PMA, OEM, etc. However, parts installed as an aircraft alteration fall under different rules which generally are in Part 43. But as mentioned above, whether a part is “eligible” for installation will fall to the installer, i.e., A&P, CRS.

Here’s an article on TSO vs non-TSO that may clear things up or confuse you more.
https://www.valavionics.com/installation-in-type-certificated-aircraft.html

FWIW: a TSO does not fall under aircraft certification where your TCDS and CAR3 does. A TSO is a minimum standard for various aircraft articles, but there's not a TSO for every article. A TSOA is an FAA approval for the design and production of an article per a specific TSO, but it's not an installation approval. So there is no direct relation between TSO and TCDS/CAR3.
 
Clip4 said:
A TSO is a minimum performance standard for
Click to expand...
paperwork.
FTFY.

SixPapaCharlie said:
So how does one find out if they can put a gauge in their plane?

How do I know what CHT I can buy and have installed legally?
What is the process for determining this?
Click to expand...
Nobody knows, as this thread clearly documents.

If your A&P/IA thinks it's OK, then go ahead and do it.
 
Will Ware said:
So now I'm trying to find instruments to rebuild with and I'm being told they HAVE to be TSO to be installed in a certificated aircraft.
Click to expand...

This thread and other sources suggest that this is not the case. Who is telling you the instruments must be TSOd? The original Stinson instruments certainly weren't.

To further illustrate the convoluted beliefs with what is acceptable and what is not, I helped with importing a Stinson from Canada last summer. It had Stewart Warner fuel level gauges as well as oil pressure, oil temperature, and an ammeter. These were not "aircraft" instruments nor were they TSO. The DAR didn't like the fuel gauges or the fuel senders they were attached to and wanted them out of there but didn't say a word about the other SW instruments that were installed right next to it. I never got a firm answer on why he only had a problem with some of the instrumentation, but once new senders and an STCd fuel gauge was installed and calibrated the airworthiness certificate was issued.
 
Once we get past the legal gyrations, we come to the reality of it.
The owner decides if it can be safely installed and if so, has it done. (log entry?)
He takes the chance that the IA will ignore it at annual time (my guess is 99% will not even notice what is in the panel).
"It just appeared"
 
SixPapaCharlie said:
Looking for a Fuel Flow and CHT gauge for our plane.

I see several on Chief that are way cheaper then the $8000 quote I just got to have an EDM700 installed. :yikes:

I understand TSO has something to do with what aircraft they are allowed on.

How can I determine if a gauge is allowed on my aircraft?
Click to expand...
I'll install a EDM700 for $7000 if you want to save a grand.
 
silver-eagle said:
And now we know why it costs so much to own and fly airplanes. Well, that and lawyers who would be happy to sue every manufacturer who has a part on the aircraft when it falls out of the sky.
Click to expand...
Don't forget those of us who defend them. We need to eat, too!
 
Is it just me? Does anyone else smell a "Just Plane Silly" explanation about to be released on video? :D
 
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