When is a TSO required?

[voorheesh]

I appreciate these 2 experienced IAs sharing this information and really don't care whether the exact topic is related to TSOs or approved parts. These are important issues and the rules are more legalese then straight forward language. Your references are very helpful to the average owner/pilot gaining understanding. I believe it is good for aircraft owners to have some insight on approved parts, A&Ps certainly "should" have this knowledge, and IA's "must" have it. Thanks for letting the rest of us in on this discussion!

[BEEZERBOY]

the cigar lighter would be a Cessna part number... thats the theory... but every day somebody puts in an Autozone receptacle. there are a host of small parts that fall into that area... switches, relays, etc they may even have been made by the same company that made the ones for Cessna. not 100% legal unless there is some kind of approval. on the other hand.... hard to prove that some of these parts aren't OEM. I think the FAA has turned a blind eye to some of it because of that reason. (as long as you don't crash)

but........ from AC20.62, you might be able to make a case for it only needing to be inspected prior to installation:

"Discrete Electrical and Electronic Component Parts. Electrical and electronic parts, such as resistors, capacitors, diodes, and transistors, if not specifically marked by the equipment manufacturer’s part number or marking scheme, may be substituted or used as replacement parts, provided that such parts are tested or it is determined that they meet their published performance specifications and do not adversely affect the performance of the equipment or article into or onto which they are installed. The performance of such equipment or article must be equal to its original or properly altered or repaired condition. Integrated circuits such as hybrids, large scale integrated circuits (LSIC), programmable logic devices, gate arrays, application specific integrated circuits (ASIC), memories, CPU’s etc., are not included because their highly specialized functionality does not readily lend itself to substitution."

bearing in mind that the above, like all ACs, have no regulatory power and are not approved data.... not even AC43.13. (on the other hand a good case for CAM 18 might be made... which is its predecessor & was concurrent with CARs)

trust me... it drives mechanics insane too. sometimes we know what works, but not allowed without a huge hassle. the list is long.... but thats why you'll see mechanics sticking to the known references.

[T. C. Downey]

trust me... it drives mechanics insane too. sometimes we know what works, but not allowed without a huge hassle. the list is long.... but thats why you'll see mechanics sticking to the known references.

As long as those references are interpreted in the way they were written we are ok. but many mechanics read into the regulations what they were never meant to say.

Fit. form and function rules.

was the item made to do the job?
is it aviation quality?
was it made by a properly authorized manufacturer.

just because the part has a manufacturers part number on it does not mean you can't use a different manufacturer.

Gyros are a prime example

[n2582d]

... bearing in mind that the above, like all ACs, have no regulatory power and are not approved data.... not even AC43.13.

Beezer, this was true with earlier revisions of AC 43.13-1 and -2. The forward to these earlier Advisory Circulars uses the term "acceptable". However, AC.43.13-1B and -2B are, with certain stipulations, approved data. Here's the Forward to AC42.13-1B:

43.13-1B - Acceptable Methods, Techniques, and Practices - Aircraft Inspection and Repair ...
This advisory circular (AC) contains methods, techniques, and practices acceptable to the Administrator for the inspection and repair of nonpressurized areas of civil aircraft, only when there are no manufacturer repair or maintenance instructions. This data generally pertains to minor repairs. The repairs identified in this AC may only be used as a basis for FAA approval for major repairs. The repair data may also be used as approved data, and the AC chapter, page, and paragraph listed in block 8 of FAA form 337 when:
a. the user has determined that it is appropriate to the product being repaired;
b. it is directly applicable to the repair being made; and
c. it is not contrary to manufacturer’s data.

AC43.13-2B -- having to do with aircraft alterations -- says much the same thing:

1. PURPOSE. This advisory circular (AC) contains methods, techniques, and practices acceptable to the Administrator for the inspection and alteration on non-pressurized areas of civil aircraft of 12,500 lbs gross weight or less. ... This data generally pertains to minor alterations; however, the alteration data herein may be used as approved data for major alterations when the AC chapter, page, and paragraph are listed in block 8 of FAA Form 337 when the user has determined that it is:
a. Appropriate to the product being altered,
b. Directly applicable to the alteration being made, and
c. Not contrary to manufacturer’s data.

the cigar lighter would be a Cessna part number

For what it's worth the Cessna 170 cigar lighters were manufactured by Cuno, a popular automotive cigar lighter company at the time.

[BEEZERBOY]

ya, I knew that about the "approved" data in 43.13, but it has been that way defacto for years, even before the change, the only difference is you don't need the signature in block 3 of the 337 (I used to get that on a phone call). note that the introduction still says

"The repairs identified in this AC may only be used as a basis for FAA approval for major repairs"

but I guess you are right.... parts of 43.13 are approved FOR MAJOR REPAIRS AND ALTERATIONS (when directly applicable)... what I should have said was the majority of 43.13 is not approved.... it is acceptable.... but then your parts books arn't approved data either. there is no other AC I know of that has approved data in it (though it may exist).... all ACs for the last 10 years or so go out of their way to say they are not approved data.

I was on a committee to generate data for the last big update to 43.13.... we tried to straighten out some of the confused parts of -1 and update some of the standards. also tried to have them put more into -2 for alterations as approved data for things that are well known and have a long history of being effective. things like wheels, tires, and brakes, extended baggage, seaplane doors etc.... long list... most of our input was ignored. I believe they made 43.13 worse in many ways.... more complicated and more confusing than the older versions.

BTW.... heres a clip from my PMI via email...
Hi xxx,
Typically non-TSO parts of any kind are not eligible for installation in certificated aircraft unless they have their installation approved by STC or some other means. There are exceptions of course. Were these flight instruments from a certificated aircraft or are we talking new instruments that were manufactured for the experimental market?

Thanks
xxxxxxxxxxxxxxxxx
Principal Avionics Inspector
Flight Standards District Office

[GAHorn]

That phrase "some other means" covers a lot of ground. .... which may even include "minor" alteration. A cigar lighter receptacle from West Marine is every bit as airworthy as one made by Cuno and sold by Cessna. An accident investigator would have a hell of a time proving otherwise if any adverse events occured.

That POI is certainly incorrect in many instances as regards the installation of TSO'd equipment. All one has to do is look at avionics. The passenger-service-unit lighting fixtures installed by a CRS in my employer's Hawker were common automotive equipment, the only change being the wire connecting them to the electrical system..... a minor alteration in every sense.....no such thing as a TSO for those items.

[BEEZERBOY]

.... so did you go to Autozone to buy the fixtures? or did they come in a bag with Hawker P/N on them

folks, I'm not hearing anything different from my FSDO.... they are sticking with the requirements of 21.9... if it isn't in there.... you can't use it without an STC, a sign off from a DER, an 8130-3 or some other approval. (don't worry, I didn't give them your name )

so does part 21 apply to you.... yes... from the preramble on Airworthiness Certificates: "A standard airworthiness certificate remains valid as long as the aircraft meets its approved type design, is in a condition for safe operation, and maintenance, preventative maintenance, and alterations are performed in accordance with 14 CFR parts 21, 43, and 91. "

on the back of your Airworthiness Certificate it says pretty much the same thing. if not, it is out of date.

the world changed in about 1956 or 57. prior to that, an aircraft recieved a "periodic" inspection and a new airworthiness certificate was issued with a termination date every year. after that, the A/W certificate was issued with no time limit, but the requirement to maintain in accordance with current regulations was added. when the CAA became the FAA all the current reg numbers became the standard.

don't hang the messanger (he's already hung), just tellin you the story as it has been told to me pretty much all through my career. now as noted... it would be impossible to tell on a lot of small items

[T. C. Downey]

folks, I'm not hearing anything different from my FSDO….

And you won't because they already told you " or some other approval. I'll not repeat what George said because you can look it up.

They are sticking with the requirements of 21.9... if it isn't in there.... you can't use it without an STC, a sign off from a DER, an 8130-3 or some other approval.
That is not what the regulation says. It says you can not produce with out certification

so does part 21 apply to you.... yes…
Certainly, it prevents you from manufacturing and selling parts with out certification and tells what you need such as FAA parts manufacturing authority

from the preramble on Airworthiness Certificates: "A standard airworthiness certificate remains valid as long as the aircraft meets its approved type design, is in a condition for safe operation, and maintenance, preventative maintenance, and alterations are performed in accordance with 14 CFR parts 21, 43, and 91. "

on the back of your Airworthiness Certificate it says pretty much the same thing. if not, it is out of date.

OH BY THE WAY,, there is no ack to a AWC.

My AWC for 3934V was issued last month and there is nothing on the back

[BEEZERBOY]

ok...not on the back now... it's in block 6:

TERMS AND CONDITIONS
Unless sooner surrendered, suspended, revoked, or a termination date is otherwise established by the FAA, this airworthiness certificate
is effective as long as the maintenance, preventative maintenance, and alterations are performed in accordance with Parts 21, 43, and
91 of the Federal Aviation Regulations, as appropriate, and the aircraft is registered in the United States.

and from ORDER (as in court order) 8130.2G, page 3.2:
b. A standard airworthiness certificate remains valid as long as maintenance, preventive
maintenance, and alterations are performed in accordance with 14 CFR parts 21, 43, and 91.

in my 40ish years as a mechnic Part 21 has always been the reference for what constitutes an elegible aircraft part. you think you can out smart the reg but you can't. it's like using the word "rebuild".... a mechanic can not use that in a log entry... only the manufacturer can... I know someone who's license was suspended for that even though he had all the same arguments you use here. you want to fight them... go for it. like I said, it's all good until you crash.

go back and read the definitions on the first page of AC20.62 that I referenced... it confirms that Part 21 is intended as the guide for eligible parts.

p.s. I don't need anybody's help on "other approvals"... pretty sure I know more about it than you do

p.p.s. your insurance is no good if the aircraft is not "airworthy"... go read some NTSB reports if you want to see how far they dig into an aircraft and it's records

[GAHorn]

If the part/material meets some approval basis...that basis does not become invalid simply because Autozone sells it.
In the case of the PSU's in the Hawker the fixtures came from a local electrical supply house and had no connection to the airplane mfr'r. The installation met whatever approval any other corporate jet custom interior might meet.

As for smaller aircraft like ours...
There are many ways in which to utilize parts other than TSO or OEM on certain aircraft. (those built before Jan 1, 1980, weighing less than 12,500 lbs, recip powered, unpressurized.) Inspector Anderson of the Detroit FSDO addressed this at the Benton Harbor Mx Seminar.
AC23-37 (see the MX library) lists some of the parts/materials which may be substituted in aircraft which do not meet PMA, TSO, or many other usual approvals.
In particular, Section 7, para c, states in part:
"(1) You may use the subtitute part/material on secondary structures....such as ...formers, stringers...side windows...wheel bearings....
These substitutions may be a minor repair or alteration and as such can be documented with a logbook entry.
(2) You may substitute parts where a direct substitute for a part/material may be found under a mfr. part number, mil spec, or other recognized standard such as the SAE.
3. When a direct replacement is not available, you may establish the replacement part/material is at least equal to the original part/material..... (notice that "at least" clause....which, in my native language...means it CAN be "better than", contrary to what some have been told. IN fact, the preamble of this AC specifically acknowleges that modern materials may be "better" and that is a good thing.)

Very interestingly, para 4 states that if some part/material was used in some STC applicable to some OTHER aircraft....use of that data can be used to obtain approval in like aircraft. Did you get that? In other words....if some STC holder has disappeared on us, but someone has a legit copy of the data....the data may be used to gain approval of the same mods for a like aircraft.

But back to the original question... Make no mistake. TSO is not a requirement for a part to be installed in our aircraft. In fact, TSO does not authorize installation in a certificated aircraft. Standard procedures must be followed for installation or modification of a certificated aircraft. Importantly and significantly, TSOs and PMAs are not required for parts mfr'd by an owner for maintaining or altering his own product.

[BEEZERBOY]

I agree with almost everything you have said. Also, I in the past have gotten many field approvals using "like data" from other STCs and prievious field approvals. That practice pretty well dried up about 7-8 years ago & the FAA (here) is very reluctant to accept that method these days. You can use them as a guide line, but not quoted in the 337 as a reference. actually, 337s prior to about '56-7 were engineer approved data.... you might make a better case with that. They have also adopted the stance that for a given mod, no field approvals will be issued if an STC exists for that alteration.

the part we disagree on is the use of TSO flight instruments in type certified, standard catagory aircraft. sure, in theory there is a way that "other methods" (from AC20-62) might be used to approve the instrument, but the reality is that the standard for flight instruments are the TSOs. how can you meet the requirements of that bit in 20-62 anyway... how can you tell that an instrument meets a type design? does a mechanic have the authority to examine and test an instrument to determine it's airworthiness? I don't think so... it's not in part 65 as a privelege of the certificate, in fact the opposite...all you can do is install and apply range markings (to the airframe). I talked to 3 instrument shops, they all said no can do. one said he would test it but 80% of those he tests fail the tso requirement. the radio was a different story, they were pretty much ok with that on a non IFR craft (though I'm sure the FAA will maintain the must be tso stance)...call your local instrument shop & see what they say.... who knows, you may get a different answer

Just tryin to save some heartache down the road. ask yourself this... why is compliance with part 21 included as a requirement on the airworthiness certificate? an aircraft manufacturer could use anything they wanted to.... it became approved per the TC. to replace an instrument would require that you buy the manufacturer's part number.... a different REPLACEMENT part falls under Part21.

from AC 21.29 on Suspected Unapproved Parts:
b.
Approved Parts. This AC uses the term “approved parts” in a colloquial sense. The term approved parts is not synonymous with “a part that has received a formal FAA approval.” Identify approved parts as parts that have met one of the following requirements:
(1) Produced in accordance with a Parts Manufacturer Approval (PMA) issued... (the rest is the list from 21.9, including TSO)

and:
p.
Unapproved Part. A part that does not meet the requirements of an approved part (refer to definition of approved parts in subparagraph 3b).

and:
b.
Airworthy. To determine that the installation of a part complies with the applicable regulations, the installer of the part is ultimately responsible for establishing that the part conforms to its type design and is in a condition for safe operation (Airworthy).
c.
AC 20-62. To enable compliance with the regulations, and to offer further guidance and clarification relevant to the eligibility of aeronautical replacement parts, AC 20-62, was published. This AC includes definitions of various terms (e.g., surplus and as is) and outlines a means by which the installer can make the required determinations.
NOTE:
Aircraft parts that are for sale that are not represented as being airworthy or eligible for installation on a TC’d product are not considered a SUP. It is not contrary to the CFR, as such, to sell aircraft parts as is or for decorative purposes. It is imperative that the buyer request and receive the necessary documentation to substantiate the status of the part.

[BEEZERBOY]

and as for this...

"Importantly and significantly, TSOs and PMAs are not required for parts mfr'd by an owner for maintaining or altering his own product."


an owner produced part may still require approvals.... been there & done that. the reg is now in 21.8(d)

21.8 Approval of articles.

If an article is required to be approved under this chapter, it may be approved—

(a) Under a PMA;

(b) Under a TSO;

(c) In conjunction with type certification procedures for a product; or

(d) In any other manner approved by the FAA.

[T. C. Downey]

FAA/PMA direct replacement parts are already FAA Approved. No matter who made them. Just because Cessna used their manufacturers for parts doesn't mean you can't replace them with a different manufacturer. TSO has nothing to do with it.

Cessna used McCauley wheels, do we need a 337 and a field approval to use a Cleveland Wheel?

The Correct answer is NO, because the Cleveland wheel is a direct replacement for the defunk McCauley company. It neither needs a TSO or a FAA/PMA, STC, or field approval, simply because Cleveland now owns the production certification for the Cessna part number.

TSO, FAA/PMA, Field approvals, and STCs are all methods of authorizing the use of the part. some direct replacement parts need neither, simply because the manufacturer has used the rules in FAR part 21 to gain manufacturing authority.

And OBTW, you get no 9030-3 tag with a new part, an 8030-3 tag is nothing but proof you have a used part. You determine the airworthiness of any part, not some yokel at the repair facility some many years ago.

[GAHorn]

I agree with almost everything you have said. ...the part we disagree on is the use of TSO flight instruments in type certified, standard catagory aircraft. sure, in theory there is a way that "other methods" (from AC20-62) might be used to approve the instrument, but the reality is that the standard for flight instruments are the TSOs. ...

No. No. and No. Replacement flight instruments do NOT "have" to meet a TSO. A perfect example are the thousands of AN instruments installed in these airplanes. I have a Puerto Rican mfr'd T&B in my airplane made by the same folks that made the one in my Baron, and it never met any TSO. (It did meet other standards, however.)

Everyone whose mx people are telling them replacement equipment "must" be TSO'd should contact their FSDO, IMO.

Additionally there is absolutely NO requirement for a comm radio to meet TSO, either VFR or IFR.

[BEEZERBOY]

I have talked to my FSDO... they say needs a TSO on required instruments A/S, Altimeter, compass for sure. I also talked to 3 instrument shops... same story

if yours says something different I like to see that... in writing.... show me & I'll believe

or better yet, give me a phone number for your FSDO & I'll call them myself