Required parts for your aircraft must be approved IAW FAR 21.305. If you are installing avionics, instruments or gages that are REQUIRED for your aircraft under part 23, 23, 27, 91, 121 or 135, they must be TSO or PMA parts. If the items are not required, (example C/D or DVD player, WSI) then they do not have to meet the approval process of 21.305.
TSO'd products are made to a standard, and anyone who makes that part must make it to the same standard so the part is always the same. What makes a TSO product better than a non-TSO'd product? I would say it depends on the product. If you are buying a CD or DVD player it wouldnt matter. If you are installing a GPS antenna, then you would want an antenna TSO'd to standard C129.
PMA parts are not blanket coverage to install on all aircraft. A PMA part has a eligibility list for which aircraft it may be installed. Example, Concord batteries are not TSO'd, they are PMA'd. If you buy one for your aircraft, Concord has a eligibility list that shows certain part number batteries and on which aircraft they may be installed. Many mechanics believe that because the part is PMA it can go on any aircraft. Not true. That PMA part is only approved to be installed on certain aircraft and you must get the eligibility list from the PMA holder. However, you can install a PMA part that is not eligible for your aircraft by getting a field approval from your local friendly FAA inspector.
How can I know which items are "required" for my 172? Is a radio required? Says who? I know fuel gauges, oil gauge, tach, etc. are required along with other certain "minimum" equipment. But who says certain avionics are required? Where does it say this?
Also, is it not true that some TSO'd parts are also sold as non-TSO'd for lots less money? Same identical products? If so, why pay more for *them* ?
The items required for your aircraft are found in FAR 23, subpart F, titled "Equipment." 23.1303 and 23.1305 specifically lists required instruments for flight/navigation and for powerplants. Also, read more of subpart F and it tells of other equipment required, & how and where they must be installed. This is very interesting reading for mechanics installing required or non-required equipment in aircraft. These are the certifications requirements that they must be installed to. Part 23 is not only for a company manufacturing aircraft, these certification requirements are also required for any alteration that is performed after the aircraft is certificated. That means any I/A signing off a major alteration must make sure that the alteration conforms to these requirements.
In addition, there are MORE REQUIRED equipment items listed in FAR 91, subpart C. These items are required depending on if you are flying VFR or IFR. 91.205 (d) (2) specifically lists a 2 way radio communications if your are operating IFR. So if you are flying IFR you are required to have a radio, and therefore the radio must be manufactured to the requirements of FAR 21.305, (TSO or PMA).
Fascinating reading these FAR's. It seems that most people dont know about the regulations until they violate one!!!
Whether or not an avionics installation requires TSO'd avionics is a function of several items, including certification basis of the aircraft, and level of alteration caused by the installation.
If you are removing a stand-alone com radio in your personal 172 and merely installing a newer one, the change not affecting any other systems, then a non-TSO'd radio is probably just fine.
If you are removing an old obsolete 360 channel nav/com and installing a newer nav/com that will include a large panel re-do and interface with an autopilot to be operated in a Part 135 charter operation...then a TSO'd radio is likely required.
This is not a cut-and-dried topic. To be completely certain, you must determine the basis of approval for the installation. If it's a minor alteration, then no 337 is req'd and in Pt 91 ops, no TSO is likely req'd.
See FAR 1, 43.13, and CAR 3/4 and FAR 23. If in doubt, call your local avionics inspector at the FSDO.
This is actually a simple topic with a clear answer. However, we have to keep the installation process seperate from the original question, which is can non-TSO avionics parts be installed? The certification basis of the aircraft, and level of alteration caused by the installation do not determine whether a replacement part needs to be TSO or PMA. I'm sure you already know that the certification basis for most of our aircraft in this discussion is found in Part 23; the level of alterations is found in Part 43; and the certification of parts is found in Part 21.
FAA order 8300.10, change 16, has a very easy flow chart for FAA inspectors to follow regarding the field approval process. One of the guidelines in the order simply states that if the items being installed are required by any FAR, then the parts must conform to 21.305; and if the items are not required then they do not have to meet the requirements of 21.305. That is a clear statement to follow as far as what type of certification the parts must meet. You are correct for the installation process of these parts in an aircraft, to determine whether it is major or minor, and the basis for approval for the installation.
If an aircraft is operated VFR, IAW Part 91, a radio is not REQUIRED equipment and it can be a non TSO or PMA radio. In addition, if that same aircraft operated IFR, IAW Part 91, now that radio becomes REQUIRED equipment and the radio itself must be approved in a manner under 21.305 (TSO or PMA). Remember at this point we are not talking about the installation of the radio in the aircraft, but simply certification of the radio itself.
There are lots of non TSO and non PMA parts that can be installed in aircraft, and the primary factor is to determine whether or not they are required by the FAR's.
There are many aircraft flying around with fax machines, direct TV, SATCOM telephones, play stations, and lots of other items. Most of these parts are not TSO or PMA parts and that is because they are not required by the FARs. The INSTALLATION of these items in the aircraft is another story and lets not go there right now!!!!
If you fly an airplane IFR, the rule requires two way communication. Does that mean the radios used must be TSO'd? Of course not. This is an operational rule, not a certification rule. You can use a handheld walkie-talkie for the communication, but you'll be hard pressed to find one that's TSO'd. A non TSO'd radio is perfectly legal to use for IFR flight.
Sal, as you know, a field approval is issued by the FAA endorsement in Block 3 of the Form 337. But Form 337 is not even required for radio installations unless they are major alterations. Since a typical replacement radio doesn't alter the type certificate data of the airplane, then no field approval is required and in most cases a replacement radio is a minor alteration or repair therefore no 337 is required either,...only a logbook entry is required. Whether or not the installation is a major alteration of the aircraft,...and whether the aircraft certification basis requires TSO'd radios or not... is the issue in this question. In short, if the airplane left the factory with TSO'd radios, then there's a good chance that replacement radios are necessary to be TSO'd. If the radio being replaced is not TSO'd then it's unlikely a simple replacement radio would have to be either.
Unless....major work such as major wiring changes are involved that may affect other systems on an airplane who's certification basis is affected.
For many privately owned/operated aircraft, non-TSO'd replacement radios are just fine and quite legal VFR, IFR not withstanding. In any case, if you have any disagreement with your installer about the issue, you should simply contact your local FSDO for an opinion.
I love to hear different opinions and interpretations, so here is another log for the fire. You mentioned about replacement radios and that possibly a non TSO radio can be installed. FAR 21.303 states that replacment parts can only be produced pursuant to a PMA, unless, 1) it is produced under a type certificate, 2) produced by an owner, 3) produced under TSO, or 4) standard parts such as nuts and bolts produced to a industry standard.
So, if a replacement radio does not conform to any of these methods how could a mechanic possible install it under 43.13? In order for a replacement part, or any part to be installed on an aircraft if MUST conform to Part 21, specifically 21.303 & 21.305.
(There are many companies and individuals producing parts and selling them to the aircraft community that are illegal, it is up to the machanic installing these parts to determine if they are qualified to be installed in an aircraft IAW Part 21)
This is why 21.305 (d) is very important. It allows the FAA to use "any other manner approved by the administrator" This is why change 16 of FAA order 8300.10 has been clarified to allow parts that are NOT REQUIRED by the FAR's to be installed on aircraft without those parts conforming to Part 21. However, the installation of these parts is another story and you are correct in your statement that it may or may not be a major alteration.
yeah...what George said...
Sal, I'm guessing a second radio can be whatever you want, being that you'll never be required to use it....as long as it's installed "properly".
This may help answer the original (seemingly simple) question.
I am giving consideration to "upgrading" my avionics.
Eastern Avionics' website <http://www.avionix.com/aindex.html> has a wealth of information on it.
Due to this thread, I sent them an email re; my future upgrade, asking "when/where/why would I consider TSO avionics as opposed to non TSO"...I would be flying occasional IFR. Their reply was simply put and read as follows.
Non-TSO radios can be installed in your aircraft with the FISDO's approval; they require a 337 for each piece. Please do not install non-TSO radios before getting the FISDO approval as if you install it and they don't approve the installation, it would have to be taken out. The only non-TSO radio that can be installed and then the paperwork sent in is the KX-170B as it is grandfathered in. TSO'd radios allow for a quicker installation as they do not require FAA approval to install. All the newer IFR equipment is TSO'd. Let me know when I can be of service.
Not that all the "finer points" and regs mentions above haven't been informative.
I think the above pretty much sums it up...no?
blue skies to all...
The reply you received is correct. Your non TSO radio will require FSDO field approval. When you take your 337 to the FSDO they will use FAA order 8300.10 change 16, to determine if they can field approve it. That document containes a flow chart, which guides them through the process, basically following yes and no answers to questions. Near the end of the process are the final 2 questions that are asked. 1) is the equipment being installed required under CFR's 23, 25, 27, 29, 91, 121. or 135? If the answer to this question is no, then the inspector can and usually will sign block 3 (providing all the installation data is sufficient). If the answer is yes, then the inspector follows the flow chart to the next step which asks the question "is the equipment PMA'd, TSO'd or STC'd per CFR21.205". ---- Here is the kicker----If the answer to this last question is no, then the flow chart directs you to a box that says "obtain approval for the equipment". I havent yet met a FSDO inspector that will field approve parts that were not produced under 21.305, IF THEY WERE REQUIRED BY THE FAR'S.
FAR's usually bore me to death, but if you want to read an interesting documet, read the above order 8300.1, change 16. You will be amazed by the advice and requirements listed in this document.
Another good place to look for regarding required items on an aircraft is the good ol' Type Certificate Data Sheet. Some items you might think are optional are sometimes required by the TCDS. For instance, for my '65 172 a specific spinner is shown. Those items are usually shown as "per drawing xxxxxx", or similar. Alternate items are also shown, usually in the Notes section. All in all, the TCDS is a good piece of information for any owner/pilot. It shows what placards are required where, speeds, weights, control travels, and much, much more. For instance, someone (Bob) mentioned gauges. They are covered sometimes specifically, like airspeed or tach instruments.
I always have a current copy of the TCDS handy when I'm annualling someone's airplane. Handy reference!
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