Transponder test question

[lostpilot28]

OK, this question is for those that really know the answers! I don't mind commentary, but I am trying to get my transponder test done, and i'm running into some roadblocks.

My avionics setup is 2 EFIS systems that have altitude encoding capability. They feed that data into a Garmin GTX-327 transponder. The local (and only) mobile avionics repair guy said that he cannot certify my transponder being that my encoder is not TSO'd.

I asked him what section of the FAR he was looking at, thinking he'd say 91.413, but he said "all of them". Go figure.

My question is this - for a simple VFR transponder test and logbook signoff, do the transponder and altitude encoder have to be TSO'd? Do you have to have a pitot/static system check? Anything else you can volunteer?

Thanks!

[Radomir]

Sonny, this has been rehashed here before.. the answer is -- your avionics guy is wrong and "all of them" is not the correct answer... Pretty crappy cop-out when you don't know the answer, IMHO... Find someone else to do it for you..... plus, aren't you flying? You can fly somewhere else and have it done on-field.. you shouldn't need a mobile guy

[Mel]

I'm not aware of any FAR that states that the encoder has to be TSO'd. My Dynon has passed the test for several years, and my "transponder guy" does this for a living on everything from experimentals to GA jets.

[Mel]

Originally Posted by lostpilot28

I asked him what section of the FAR he was looking at, thinking he'd say 91.413, but he said "all of them". Go figure.

All of them? How about 91.15 for example, that deals with dropping objects from aircraft? Me thinks that's a pretty stupid statement.

[SteinAir]

As an FAA certified repair station, we do lots and lots of transponder tests on both experimentals and certified airplanes.

Your guy is just plane wrong - period. The burden is not on you to prove him wrong, it's on him to prove himself right; as is always the case with the FAA. It should be about a 15 minute job if everything is working and it should take longer to do the paperwork than the actual test. Either he is ignorant of the facts, or he has been given the wrong information by his FSDO (which often happens as well).

I'd just fly somewhere and have it done by someone that knows what they are doing. It's a short/quick test and not overly expensive...if you're around here ever you can schedule it over a fuel stop!

That's my 2 cents...

Cheers,
Stein

[rvmills]

Sonny,

For another data point, when we installed my 327 into my system (Dynon D100 for encoder), my avionics guy didn't bat an eye...just brought over a sticker and we slapped it in the logbook after the check.

If you have trouble finding a local (or closer) guy, 'cmon down from Boise to Reno and I'll hook you up with him. Wonder if your guy would accept a call from another avionics guy that could clear it up and give him a green light.

Cheers,
Bob

[az_gila]

...be more applicable - 91.215....

(a) All airspace: U.S.-registered civil aircraft. For operations not conducted under part 121 or 135 of this chapter, ATC transponder equipment installed must meet the performance and environmental requirements of any class of TSO-C74b (Mode A) or any class of TSO-C74c (Mode A with altitude reporting capability) as appropriate, or the appropriate class of TSO-C112 (Mode S).

..but luckily, the TSO approved Installation manual for the 327 only calls for a TSO on the antenna and transponder itself.

Your guy should go by 91.215 and the FAA approved Installation Manual.

The 91.413 tells you to perform the checks, and references Appendix F here on the "how to", but no mention of approvals...

http://www.ferrer-aviation.com/pdf/AppendixF.pdf

Print out the stuff and take it to him...

Originally Posted by lostpilot28

OK, this question is for those that really know the answers! I don't mind commentary, but I am trying to get my transponder test done, and i'm running into some roadblocks.

My avionics setup is 2 EFIS systems that have altitude encoding capability. They feed that data into a Garmin GTX-327 transponder. The local (and only) mobile avionics repair guy said that he cannot certify my transponder being that my encoder is not TSO'd.

I asked him what section of the FAR he was looking at, thinking he'd say 91.413, but he said "all of them". Go figure.

My question is this - for a simple VFR transponder test and logbook signoff, do the transponder and altitude encoder have to be TSO'd? Do you have to have a pitot/static system check? Anything else you can volunteer?

Thanks!

[lostpilot28]

Thanks for all the help, fellas. I'm going to call this guy on Monday and just "inform" him, although I know how it will go. He's kind of a know-it-all, so I doubt he'll change his mind.

[lostpilot28]

OK, Round 2. I spoke with the local FSDO office this morning and he pointed out FAR 91.217. Note paragraph c, below.

91.217 Data correspondence between automatically reported pressure altitude data and the pilot's altitude reference.

No person may operate any automatic pressure altitude reporting equipment associated with a radar beacon transponder—

(a) When deactivation of that equipment is directed by ATC;

(b) Unless, as installed, that equipment was tested and calibrated to transmit altitude data corresponding within 125 feet (on a 95 percent probability basis) of the indicated or calibrated datum of the altimeter normally used to maintain flight altitude, with that altimeter referenced to 29.92 inches of mercury for altitudes from sea level to the maximum operating altitude of the aircraft; or

(c) Unless the altimeters and digitizers in that equipment meet the standards of TSO-C10b and TSO-C88, respectively.

By what the FSDO guy told me, it would seem that anyone and everyone using altitude reporting equipment (transponder, altimeter, encoder) are in violation of this rule if their equipment isn't TSO'd. Wouldn't that to just about every experimental EFIS company out there (Dynon, MGL, Blue Mountain, etc)? I think there are also a lot of experimental aircraft out there with non-TSO'd altimeters.

[Tandem46]

Originally Posted by lostpilot28

(b) Unless, as installed, that equipment was tested and calibrated to transmit altitude data corresponding within 125 feet (on a 95 percent probability basis) of the indicated or calibrated datum of the altimeter normally used to maintain flight altitude, with that altimeter referenced to 29.92 inches of mercury for altitudes from sea level to the maximum operating altitude of the aircraft; or

(c) Unless the altimeters and digitizers in that equipment meet the standards of TSO-C10b and TSO-C88, respectively.[/i]

Sonny, look more closely, there is an "OR" after part (b) which is to say you need to meet (b) or (c) not both. At least that's how I'm reading it.