A&P guys - what avionics can you touch?

alfadog

alfadog

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alfadog
So I am trying to understand what avionics an A&P can work on. I am getting somewhat confusing responses from folks here.

We are talking about a certificated airplane here, let us say a 1976 Cessna 172M.

I will go through what I have researched so far. Please add/correct me and provide the regs if you know them.

First, FAR Part 65.

§ 65.81 General privileges and limitations.
(a) A certificated mechanic may perform or supervise the maintenance, preventive maintenance or alteration of an aircraft or appliance, or a part thereof, for which he is rated (but excluding major repairs to, and major alterations of, propellers, and any repair to, or alteration of, instruments)...​

That seems pretty clear. An A&P cannot touch the instruments. Can an A&P remove a turn coordinator, send it out for overhaul and reinstall the repaired unit? One of my A&P instructors said he can remove it but not reinstall it.

What about radios? It seems to me that the FCC General Radiotelephone Operator License (GROL) gives one permission to work on radios:

Radio Maintenance and Repair

You need a commercial operator license to repair and maintain the following:
...
- All aircraft stations and aeronautical ground stations (including hand-carried portable units) used to communicate with aircraft.​

So who can work on instruments? It seems only FAA Certified Repair Station under FAR Part 145.

And what is an instrument?

(e) Instrument ratings.
(1) Class 1: Mechanical. A diaphragm, bourdon tube, aneroid, optical, or mechanically driven centrifugal instrument used on aircraft or to operate aircraft, including tachometers, airspeed indicators, pressure gauges drift sights, magnetic compasses, altimeters, or similar mechanical instruments.
(2) Class 2: Electrical. Self-synchronous and electrical-indicating instruments and systems, including remote indicating instruments, cylinder head temperature gauges, or similar electrical instruments.
(3) Class 3: Gyroscopic. An instrument or system using gyroscopic principles and motivated by air pressure or electrical energy, including automatic pilot control units, turn and bank indicators, directional gyros, and their parts, and flux gate and gyrosyn compasses.
(4) Class 4: Electronic. An instrument whose operation depends on electron tubes, transistors, or similar devices, including capacitance type quantity gauges, system amplifiers, and engine analyzers.​

Comments?
 
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Removal and installation of instruments are not repairs to them.

If you have the certifications you can work on any thing, most A&Ps don't have FCC certifications to work on transmitters.

I'm legal to install radios, that is to wire the aircraft and all that, but I don't, unless it is a pre-wired harness that has been tested on the bench, simply because it is too easy to cross a wire and smoke the radio.

What is a instrument? pretty much any thing in the instrument panel that has a glass face.
 
alfadog said:
T...Can an A&P remove a turn coordinator, send it out for overhaul and reinstall the repaired unit? One of my A&P instructors said he can remove it but not reinstall it.

...
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Looks like another instructor needs some remedial training in what privileges come with the certificate.

Basically, anybody can remove something from an aircraft rendering it unairworthy. To make it airworthy, you have to be legally entitled to sign a return to service. An A&P can install radios and instruments and sign the return to service. Whether a particular A&P will do any particular job depends on whether he feels he is competent to do it, has the proper tools and required tech data.
 
Generally speaking, an A&P can install, remove, and reinstall any instrument or piece of avionics. Only an properly FAA-certified instrument/radio repair station or FCC-licensed technician (as applicable) can go inside the box/instrument itself.
 
Many A&P's simply do not have the tools to install the huge array of different style pins that accompany the connectors on modern aircraft radios.
 
More or less what has been said already. I'll give a few examples from my experience.

We upgraded the 530 to a 530W. Our A&Ps did the work.
We installed a used KWX56 in the plane. Our A&Ps didnwant to do the work because they lacked the wiring tools that weren't required for the 530-530W upgrade, so we had an avionics shop do the work.
 
A&P's need to know their limitations on transponders. If testing is required post maintenance of the system an A&P cannot do it under their A&P certificate per 91.413.


AC 43-6C provides guidance on when and what testing is required after maintenance.
 
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bnt83 said:
A&P's need to know their limitations on transponders. If testing is required post maintenance of the system an A&P cannot do it under their A&P certificate per 91.413.


AC 43-6C provides guidance on when and what testing is required after maintenance.
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Yep, I put one in once, but it had to get checked afterwards.
 
Skylane81E said:
Yep, I put one in once, but it had to get checked afterwards.
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Have an ATP rated owner who did the "slide-out slide-in replacement" with no documentation anywhere. My log entry will read something like this:

Found Narco AT165 P/N 12345 S/N 6789 installed, a direct replacement for the previously installed ARC 365. No wiring or structural changes required. Unit self-tests satisfactorily. Updated W&B and Equipment Lists. Placarded "INOP" due to 91.413 testing requirements.
 
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I have an FCC license and I have most of the tooling however, the manufacturers make it difficult for anyone outside of their dealership networks to obtain the equipment and technical material required for installation and maintenance of their products. Couple that with the fact that some of these boxes are the price of an entire airplane, you're not likely to find anyone willing to get involved in such projects.
 
bnt83 said:
Have an ATP rated owner who did the "slide-out slide-in replacement" with no documentation anywhere. My log entry will read something like this:

Found Narco AT165 P/N 12345 S/N 6789 installed, a direct replacement for the previously installed ARC 365. No wiring or structural changes required. Unit self-tests satisfactorily. Updated W&B and Equipment Lists. Placarded "INOP" due to 91.413 testing requirements.
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A lot like mine, just I took credit for swapping from the OE BK unit to a GTX327 we had laying around.

A few hours later it was tested and ready to go.
 
bnt83 said:
Many A&P's simply do not have the tools to install the huge array of different style pins that accompany the connectors on modern aircraft radios.
Click to expand...
to instal the "king" and "Narco" pins the pliers can be bought at radio shack. and the pin connectors can be bought at AS&S.

most all the glass cockpit displays are wired by tape connectors that your computer uses.

IF --- you would like to do the wiring, and show me the radio stack works, you make the log book entry, I'll sign the log as "under the supervision of" but if the smoke gets out, don't cry to me.
 
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Ron Levy said:
Generally speaking, an A&P can install, remove, and reinstall any instrument or piece of avionics. Only an properly FAA-certified instrument/radio repair station or FCC-licensed technician (as applicable) can go inside the box/instrument itself.
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Can the A&P change the glass in a gyro? it's held in by a snap ring accessible from the front of the gyro, and can be done with out removal from the panel.
 
Tom-D said:
most all the glass cockpit displays are wired by tape connectors that your computer uses
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No they really aren't Tom. The pin outs and options that may or may not be installed in the aircraft don't lend themselves to work with those. They are mostly wired with subminiature D connectors and individual wires. Grounds are terminated into ground blocks that accept multiple machined pins.

Maybe you can give us an example other than the Gray code ribbon cable between a transponder and encoder :dunno:

Edit : Ribbons don't make sense because each wire bundle has wires exiting that bundle and joining other boxes. And most of these individual wires, twisted pairs triples etc are shielded. The shields are also terminated inside the D connector on a ground lug.
 
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Tom-D said:
Can the A&P change the glass in a gyro? it's held in by a snap ring accessible from the front of the gyro, and can be done with out removal from the panel.
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Based on my research and what I am learning here, I would say no. It is a repair on an instrument.
 
alfadog said:
Based on my research and what I am learning here, I would say no. It is a repair on an instrument.
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That is how I see it too, but the cousin of the compass ferry does it quite often.

Specially when a pilot thinks by breaking the glass on the interments will give them better static pressures.
 
bnt83 said:
No they really aren't Tom. The pin outs and options that may or may not be installed in the aircraft don't lend themselves to work with those. They are mostly wired with subminiature D connectors and individual wires. Grounds are terminated into ground blocks that accept multiple machined pins.

Maybe you can give us an example other than the Gray code ribbon cable between a transponder and encoder :dunno:

Edit : Ribbons don't make sense because each wire bundle has wires exiting that bundle and joining other boxes. And most of these individual wires, twisted pairs triples etc are shielded. The shields are also terminated inside the D connector on a ground lug.
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Yep, and when coupling up with some of the older card edge connectors, the ribbon cable just won't work.
And the new pins that come with the D-sub connectors, require that you purchase a very expensive tool to crimp them with. Or you can run down to radio shack and get a ribbon of the older molex style pins. But those require finesse to use, which is why they went to the new kind for aviation.
That said, most A&Ps out there don't have the simple hand tools needed to make up a radio harness, and due to the expense of making the purchase of those tools, and not really interested in doing avionics installations anyway, they defer that work to avionics shops.
Then couple that with the simple color coding of most aircraft wiring. (All White)
 
bluerooster said:
......That said, most A&Ps out there don't have the simple hand tools needed to make up a radio harness, and due to the expense of making the purchase of those tools, and not really interested in doing avionics installations anyway, they defer that work to avionics shops.
....)
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Kinda makes you wonder how all of us experimental guys have successfully installed our cutting edge electronic stuff without letting out all that "magic smoke".......;):)
 
N801BH said:
Kinda makes you wonder how all of us experimental guys have successfully installed our cutting edge electronic stuff without letting out all that "magic smoke".......;):)
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We know you guys are all above average! :yes:
 
N801BH said:
Kinda makes you wonder how all of us experimental guys have successfully installed our cutting edge electronic stuff without letting out all that "magic smoke".......;):)
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RS is your friend. :D
 
N801BH said:
Actually.... There is not ONE item in my experimental that came from Radio Shack... Most items came from the racing industry or over the road heavy truck industry..... YMMV...;)
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Oh, you bought th' 'spensive stuff. ;)
 
bluerooster said:
Oh, you bought th' 'spensive stuff. ;)
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Ha........

As the builder and holder of the repairmens certificate for my experimental, I can pick and choose what products that I will install in my plane.... You won't see Kelly Aerospace crap...:no:... You won't see overpriced Garmin electronics..:no:... You won't see 100 dollar apiece fine wire spark plugs...:no:... Etc Etc......

What you will find are time tested, affordable parts that give me the best and safest bang for the buck.... Other then the required transponder check, the only additional part I have had to purchase has been the data card update for the KMD150 MFD.. I LOVE my toy..:yes::)

The certified aircraft owners..... Are not so lucky..:nonod:..;)
 
N801BH said:
Ha........


.....What you will find are time tested, affordable parts that give me the best and safest bang for the buck.... Other then the required transponder check, the only additional part I have had to purchase has been the data card update for the KMD150 MFD.. I LOVE my toy..:yes::)
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The Only way to fly! :yeahthat:
 
My name is Francklin, 43 years, brazillian, 23 years of love and work with aviation. I am avionics ramp and bench techniciam. My specialties are weather radars, transponders,TCAS and Auto Pilots. I've a little, but complete workshop here in Brazil. I traveled twice by Europe ( London, Paris and Geneve ), Israel and 13 days of car per 5 states of US and visiting various maintenance companies, I observed that is getting rare to find good technical avionics of both the US and in Europe. The good are retiring and are not being trained young technicians. I consider myself a great professional, always tried to study the whole architecture of the aircraft to succeed in researches of crashes , for it sought licenses in cell and engines too. I would like to contribute my knowledge and experience, but I do not want to work illegally in any country. I am studing English and handouts to make FAA license. I am praying to God, that if He is willing, I get a legal way to work and live in the US or Europe. I know I can contribute a lot with my services and expertise . Thank you very much.
 
Francklin1912 said:
My name is Francklin, 43 years, brazillian, 23 years of love and work with aviation. I am avionics ramp and bench techniciam. My specialties are weather radars, transponders,TCAS and Auto Pilots. I've a little, but complete workshop here in Brazil. I traveled twice by Europe ( London, Paris and Geneve ), Israel and 13 days of car per 5 states of US and visiting various maintenance companies, I observed that is getting rare to find good technical avionics of both the US and in Europe. The good are retiring and are not being trained young technicians. I consider myself a great professional, always tried to study the whole architecture of the aircraft to succeed in researches of crashes , for it sought licenses in cell and engines too. I would like to contribute my knowledge and experience, but I do not want to work illegally in any country. I am studing English and handouts to make FAA license. I am praying to God, that if He is willing, I get a legal way to work and live in the US or Europe. I know I can contribute a lot with my services and expertise . Thank you very much.
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First post...

Welcome to POA....

:cheers::cheers:
 
Great place to study for the GROL is this site: www.fccradioexam.com/study.jsp
It's adaptive so it offers you the questions you get wrong more frequently in study as well as the practice test. The FCC still verbatim publishes the questions for the test pools. Alas, the FCC tests are even worse than the FAA tests. There's references to things that are obsolete (the rules of changed), questions where one of the answers is **** or the units are wrong. One question is really bogus in that it has the correct answer written as both 1800 hz and 1.8Khz. The latter is marked wrong even though it's the same quantity.

Element 1 is general radio law (totally irrelevant for what the GROL is authorized to do these days), Element 3 is the GROL theory section. That's all you need PERSONALLY.
Of course, if you want to work on airframes, etc... you'll need an FAA airframe mechanics license. You'll need to study and pass written and practical tests plus either go through an approved school or serve an apprenticeship period.

However, to do a lot of work requires you to be under the auspices of a repair station (that would be your employer). That's more involved.

The bigger issue is getting employment authorization from CIS (our immigration) than worrying about the FAA and FCC. Brazil isn't the easiest country to immigrate from right now. You need to consult a US immigration attorney.
 
I did full panel upgrades, including IFR GPS, on 2 Cherokee 140s and Ive done a couple of STCs to replace generators with alternators on some older Cessnas. Just takes an IA that's willing to work with you and a couple hundred dollars worth of tools off of Ebay.
 
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I've done two, and working on the third. One in Cherokee 180, one in Grumman Yankee, and working on Cherokee 140.
It's not that big of a deal. just follow the directions, and remember that Cardedge connectors with letters, are A B C D E F H J K L M N P R S T U V X Y Z.
Then the majik smoke will not escape from the box.
Some of the tools are easier, (and cheaper) to fabricate than to purchase. And the crimp tool for the Dsub pins can be had on ebay for about half price.
A good quality regulated power supply is handy, And for installation a good antenna analyzer is handy to have. (don't wanna blow th finals on our new Xmitter do we?)
 
bnt83 said:
Have an ATP rated owner who did the "slide-out slide-in replacement" with no documentation anywhere. My log entry will read something like this:

Found Narco AT165 P/N 12345 S/N 6789 installed, a direct replacement for the previously installed ARC 365. No wiring or structural changes required. Unit self-tests satisfactorily. Updated W&B and Equipment Lists. Placarded "INOP" due to 91.413 testing requirements.
Click to expand...


..and the significance of this is.....?

Bob Gardner
 
Repairing, testing, or adjusting transmitters requires an FCC General Radio Telephone Operator license. Information on getting one was in my previous response to YOU.
 
flyingron said:
Repairing, testing, or adjusting transmitters requires an FCC General Radio Telephone Operator license. Information on getting one was in my previous response to YOU.
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The guy who does my transponder /encoder work, says the caliberation / cert testing for his equipment is DAMN expensive...

So that has to added into the mix...:rolleyes:
 
N801BH said:
The guy who does my transponder /encoder work, says the caliberation / cert testing for his equipment is DAMN expensive...

So that has to added into the mix...:rolleyes:
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Yes, I sort of alluded to that is that not only do you have to have the FAA and FCC paper as the technician but you need to be a repair station. That entails a whole slew of other paperwork with the FAA as well as a lot of specialized equipment. It's actually NOT quite as bad as it used to be. I recall a service monitor back twenty years ago could easily run over $20K in those day's dollars. It's better now. While you have to have a more complicated transponder test set (Mode S etc...) it's cheaper.
 
weirdjim said:
They are both marked wrong. 1800 Hz. and 1.8 kHz. respectively.

Jim
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Holy Necropost, Batman. You responded to something I posted over two years ago.

Well, I dug through my question pools. I misremembered it apparently, it's 1600 Hz and 1.8 KHz, and yes the FCC is bogus on the question:

The total bandwidth of a transmitter using A-2 emission with a modulating frequency of 800 Hz and a carrier frequency of 500 kHz is: [6-6A386]
1600 Hz Correct!
1.6 kHz Incorrect. Sorry, while this answer is correct, it's not the one the FCC is looking for.
1000 kHz Incorrect.
800 kHz Incorrect.
 
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