The International Cessna^® 170 Association

I thought I knew the answer here, but now I find myself questioning it... If you are installing new radios (as I am - strictly a VFR installation), Under what conditions are you required to install TSO'd (as opposed to a non-TSO'd version) radios? The radio shops try and steer you in that direction (because they make more on the sale), but when is it truly necessary to do so? I'm thinking I don't need TSO'd radios for a Part 91 VFR scenario.

Thoughts and/or experience?

You are correct. TSO'd radios are not required for Part 91 installations. TSO's are important when interfacing with other integrated avionics and autopilots, etc., but are unimportant (in my opinion) when simply installing stand-along coms and navs, etc..
Don't take my word for it. Go straight to the source (like I did when I got the answer for this question). Call your FSDO and ask for the avionics inspector.

Thanks George.

Just talked to the FSDO and got the exact opposite story . They said that if it wasn't listed on the TC, then they needed to be TSO'd since there'd be no way to ensure that a non-TSO'd radio wouldn't interfere with whatever radios or other avionics were onboard. They also said that the operational requirements of Class B/C (and presumably D) airspace required TSO'd radios via Part 91.

I asked about the Mitchel MX-300s that were on board when I bought the aircraft. He said that technically, I should not have been flying with them and that my AI should have caught that during the annual.

Looks like I'll be buying TSO'd radios.

Thinking about it after the fact, his comment about TSO’d radios being required to operate in Class B/C airspace doesn’t make sense. He said that Experimentals, since they do not have a certification process, are not required to use TSO’d radios. Well, if certificated aircraft are required to use TSO’d radios and Experimentals aren’t, how can both operate in Class B/C airspace? Wish I’d thought to ask that question.

Doug your FSDO guy is WRONG. A King 170B radio is not TSOd. Anybody removing them? The Garmin 150 panel mounted GPS is not TSOd and doesn't have to be removed. Older Terra and Narco radios and indicators are the same, I could go on.

There is no requirement to have a TSOd radio to enter class B, C or D. Just establish 2 way communications. You can and I have meet this requirement with a hand held radio. Ever see one of those TSOd, NOT.

BTW experimental aircraft DO have a certification process under FAR 21.191 and do not require more or less equipment than an aircraft certified under the normal category to operate in any class of airspace.

I really hate FAA guys who give out bad information.

Doug, call that guy back and tell him you need that opinion in writing. I suspect you'll either not get it, or he'll change his position. (The FAA has lots of guys in inspector's positions these days that don't know Shinola from bleep (mushrooms.) They've hired a lot of guys straight out of military inspector-type specialties that have no correlated civilian counterpart. Result: Foolish responses like the one you got.
Tell him to put it in writing. Please send me a copy.
(And Bruce,...you've got too much time on your hands, huh?)

Wow! This is almost as good as MMO and Mogas for getting people riled up

Anyway, I called the FSDO again today and spoke to two "Principal Airworthiness Inspectors", the second of which is their avionics guy. I got the same response.

The gist is this:
If it was part of the original TC (like a KX170B on an early C172) then it's fine since the factory had the authority under the approved TC to install it. However, if it was not on the TC (like an Icom IC-A200) then it needs to be TSO'd for the reason's stated in my previous response. The Class B/C airspace thing seemed to not really be an issue.

I asked for this explanation in writing. The inspector said he was leaving on vacation, but would forward it to me upon his return. I'll be bugging him for this in writing if I don't hear anything in two weeks.

Great Doug.

Our aircraft are certified under CAR3 which I can't find. I just reviewed 14 CFR part 23, Airworthiness Standards: Normal, Utility, Acrobatic, And Commuter Category Airplanes and could find no reference to the requirement of radios meeting a TSO. i could have missed it.

Make sure your FSDO guy references the exact FAR. Tell him you'll need that reference so you can read it yourself and make sure your in full compliance.

Bruce, ...where is your ELT antenna in that photo?

George how would you remember after seeing my plane once 2 years ago that my 170, which I used as a model will building this pedal car, had an ELT antenna in that location?

The key here is of course that while the pedal car in the photo is a half scale replica, it is not an EXACT scale replica.

N9149A wrote:The key here is of course that while the pedal car in the photo is a half scale replica, it is not an EXACT scale replica.

I don't know about that. You sure have a big grin on your face.

Hey Bruce, you might want to reconsider "BOYS AND THEIR TOYS"! That might be contributing to people being suspicious of where the antenna has disappeared to. Of course, all of us who are unable to do the photo work that you have done will be jealous enough to poke good natured fun at you to make up for not having that talent.

I have a 1956 C172 with an ICOM radio in it. My radio is several years old and is NOT the TSO'd version. My shop had no problems in putting it in, in fact they told me that I would have to put a TSO'd radio in only if I wanted to get my bird certified for IFR. Then the primary radio must be TSO'd and the secondary does not have to be.

Dave

doug8082a wrote:Wow! This is almost as good as MMO and Mogas for getting people riled up

Anyway, I called the FSDO again today and spoke to two "Principal Airworthiness Inspectors", the second of which is their avionics guy. I got the same response.

The gist is this:
If it was part of the original TC (like a KX170B on an early C172) then it's fine since the factory had the authority under the approved TC to install it. However, if it was not on the TC (like an Icom IC-A200) then it needs to be TSO'd for the reason's stated in my previous response. The Class B/C airspace thing seemed to not really be an issue.

I asked for this explanation in writing. The inspector said he was leaving on vacation, but would forward it to me upon his return. I'll be bugging him for this in writing if I don't hear anything in two weeks.

Are there any 170 ragwings out there that are IFR certified? My avionics man said it would be easier to have paperwork from another plane to complete the IFR certification. Thanks for any info.
John