Shop says field approval for a common radio in a common plane.

jimmyjack

jimmyjack

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Looking to bring my 172 into the 21st century (well, 20th century).

As I progress through my IR training, I need to get a second nav/com/cdi.

One shop I'm dealing with (of several), the only one so far to be even remotely responsive to my request for a quote, is stating that an older, but extremely common radio is not STC approved in my '57 172. Radio is the venerable MK-12D, but they stated all these old radios would require a field approval, grounding the plane for months.

Shop hasn't looked at my plane, only a photo of my panel. They know the N number, obviously.

This doesn't sound right to me. How can the most common plane ever made not be applicable to some of the most common nav com's ever made?

My A&P is incredulous and says they just don't want to do the job, or only want me to buy new new new. I want the Internet's thoughts, too.

Thanks!
N
 
You don't need a radio shop. Your a&p can install them him/herself with a log entry. If s/he wants to file a 337 just fill it out and sent it in to get scanned into the aircraft records, there is no "approval". Have them get to it.
 
jimmyjack said:
...is stating that an older, but extremely common radio is not STC approved in my '57 172. Radio is the venerable MK-12D...
Click to expand...

Not surprising since Narco does not and did not ever hold any STC's for anything period :dunno:

Bottom line: gonna be tough to find a shop that will install a radio they didn't sell you. An A&P could do it but you'll need an IA to file the 337.
 
And why do they think a field approval? Are you going to have to make a major modification to get the rack in place?

Venerable isn't the word I'd use for the Mk12D's. I probably would get banned for the words I generally associated with them. These things were unsupported, unreliable pieces of junk when Narco was still around to deal with them.
 
There must be a lot of misunderstanding between you and your shop. Or this is the shop's way of telling you "go somewhere else for that".

A field approval, assuming the FSDO will even give you one (vs saying you don't need one) should only take a few days...

This isn't a field approval for some sort of integrated autopilot, its a COM/VOR/GS...
 
bnt83 said:
There must be a lot of misunderstanding between you and your shop. Or this is the shop's way of telling you "go somewhere else for that".

A field approval, assuming the FSDO will even give you one (vs saying you don't need one) should only take a few days...

This isn't a field approval for some sort of integrated autopilot, its a COM/VOR/GS...
Click to expand...
There's no misunderstanding - I could copy/paste the emails. Maybe later today.

I already have one mk12 installed. They said it was done under an FA (how would they know w/o looking at paperwork (it wasn't btw, simple log book entry)). They say are saying an FA is needed for a second radio, unless of course, I buy a newer model with GPS that already has an STC for my plane.

Now, I'm new to this game, but even I know that none of that makes sense.
 
It is not a major modification and only requires a logbook entry. Add it to the W&B and equipment list. When I owned an avionics shop, all 337's used to be filed thru the FSDO. If we submitted one for filing or for a field approval, it would get rejected by the inspector because it was not a major modification. He would ask, why are you doing this. What is your FAA approved data? Now, 337's are sent directly to Oklahoma City for filing without any review, and regardless if it is a valid 337, it will get filed. Try another shop.
 
jimmyjack said:
There's no misunderstanding - I could copy/paste the emails. Maybe later today.

I already have one mk12 installed. They said it was done under an FA (how would they know w/o looking at paperwork (it wasn't btw, simple log book entry)). They say are saying an FA is needed for a second radio, unless of course, I buy a newer model with GPS that already has an STC for my plane.

Now, I'm new to this game, but even I know that none of that makes sense.
Click to expand...

My advice is to solicit quotes from other shops. Take a picture of your panel and then start emailing other shops with "Narco MK12D Install RFQ" in the subject line.

Keep in mind many shops have a separate sales department that may or may not really understand data requirements for the jobs they are quoting.
 
During quote process, they emailed this:

"Based on the STC/AML for the NAV/COM, your aircraft would be grounded for several months to complete the field approval process. This time is not guaranteed by us, it is dependent on the local FAA office approval process. Would you like me to continue the quote generation process?"

I reply: "Confused. STC for the nav com? Which one?"

They reply: "We are quoting the Garmin GNC-255A (I never asked for this but whatever), but none of the NAV/COM units that I have looked into have STC coverage for your aircraft. In turn, any Nav/Com installation will have to be field approved causing the delay on return to service."

Me: "If that's the case, you can cancel the quote."

Me, an hour later: "I already have one MK-12D - if I were to buy a second one, there should be no issue installing it, correct?"

Them: "Yes, the issue with that would be the lack of STC Installation Certification. I know it sounds odd due to the fact that you already have one installed, but the existing unit in your aircraft was installed on a field approval. As I stated earlier, the field approval for return to service, is what causes the lengthy down time. We are limited to installing only the newer NAV/COM/GPS units such as the Garmin GTN-750 or GTN-650, these units are more costly, but have STC/AML installation approvals that do not require the time consuming FAA field approvlals."
 
jimmyjack said:
During quote process, they emailed this:

"Based on the STC/AML for the NAV/COM, your aircraft would be grounded for several months to complete the field approval process. This time is not guaranteed by us, it is dependent on the local FAA office approval process. Would you like me to continue the quote generation process?"

I reply: "Confused. STC for the nav com? Which one?"

They reply: "We are quoting the Garmin GNC-255A (I never asked for this but whatever), but none of the NAV/COM units that I have looked into have STC coverage for your aircraft. In turn, any Nav/Com installation will have to be field approved causing the delay on return to service."

Me: "If that's the case, you can cancel the quote."

Me, an hour later: "I already have one MK-12D - if I were to buy a second one, there should be no issue installing it, correct?"

Them: "Yes, the issue with that would be the lack of STC Installation Certification. I know it sounds odd due to the fact that you already have one installed, but the existing unit in your aircraft was installed on a field approval. As I stated earlier, the field approval for return to service, is what causes the lengthy down time. We are limited to installing only the newer NAV/COM/GPS units such as the Garmin GTN-750 or GTN-650, these units are more costly, but have STC/AML installation approvals that do not require the time consuming FAA field approvlals."
Click to expand...

They are trying to sell you newer more expensive radios. If they can't read your request and quote what you asked for initially, why bother with them?


I had the same thing pop up when I started receiving quotes for installing used 430W, each one was within $1k of a new GTN650 (installed).

A field approval is nothing more than listing data they are planning to use in block 8 (on the back of the 337). This data can come from Advisory Circulars that exist, the equipment installation manuals etc, and some generic statement about instructions for continued airworthiness, an electrical load analysis etc. It goes to the local FSDO that requests a few changes. The revised one is resubmitted then then the FSDO stamps block 3 and the FA process is finished.


Or just use AC43.13-2B as approved data.
(Which I'd be willing to bet it is what they found on the 337 for the radio you have currently installed)

 
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jimmyjack said:
Owners can't install radios. Can they?
Click to expand...


I did. It might be a little grey, but I slid a KY-97A out of my panel and slid in an ICOM IC-210A...................signed the logs.

As far as I know completely legal as I did no wiring or tray install. Negligible weight difference.:nono::yes:
 
kgruber said:
I did. It might be a little grey, but I slid a KY-97A out of my panel and slid in an ICOM IC-210A...................signed the logs.

As far as I know completely legal as I did no wiring or tray install. Negligible weight difference.:nono::yes:
Click to expand...

Start thinking critical systems.

Slid in-out boxes can invalidate EMI/RFI compliance, compass correction card and even wiring may not be correct. Lot of radios fit trays and connectors but the lighting or other circuits are different. Even low serial # vs high serial #s of the same make/model radio.
 
jimmyjack said:
Owners can't install radios. Can they?
Click to expand...

An inmate in the local looney bin can install radios. The trick is to find an Airframe mechanic willing to sign off the installation in the logbook as a minor installation.

The FAA went so far as to issue an advisory circular to mechanics on how to differentiate a minor from a major alteration. Minor alterations are signed off in the airframe logbook. Major alterations require a 337 form and field approval.

The EXAMPLE in the AC of a minor alteration is a simple radio installation not involving modification of critical airframe structure.

Jim
 
Even the blanket STCs rarely cover modifying critical structures.

But

A 1957 Cessna 172 should be a no-brainer
 
I have a copy of the Narco Avionics MK-12D installation manual and it does state in section 1-4 that an FAA Form 337 must be filed although there is no explanation as to why.

From the correspondence you quoted it appears pretty obvious that the shop is not interested in doing this job but would be very happy to accommodate you should you decide to purchase a new Garmin from them. In fact it would be interesting to see their response if you told them to go ahead and start the field approval process. You'd probably not get any more responses from them.
 
Two questions:

1. Why are you still effing with a shop that clearly doesn't want your money?

2. Why are you installing an antique radio?

Find another avionics shop and have them install something designed in this century. You'll be happier all the way around.

Or, do like I did, and jump into the experimental aircraft world. Then you can install any nav/com you'd like to install.
 
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