Narco AT165 on the fritz

MedFlightDoc

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Curious if any ideas can be had out there...

I've got a Cessna 172C with a Narco AT 165 in it. The transponder is fairly new, from a few years back, and was a straight plug into the old Cessna model transponder that lived in the panel when I bought the plane (the kind with the white face). That was the main reason I went with that model, because it was a plug and go change without any other hastle.

Now, the transponder squaks ok, but the pressure altitude for the most part seems stuck on "-1000 ft" in the display, and then will wildly vary between "-1000" to 35,000 to 10,000, to anywhere in between before occasionally settling down and showing the correct pressure altitude. Of course this get on ATC's nerves and they call me out on it and ask me to turn the alt off and just squak my code.

Any thoughts on what might be the problem, and how to fix it?

Thanks!
 
IME, the best thing you can do when you have Narco equipment on the fritz is to pull it out, throw it in the trash, and replace it with something that doesn't suck.

We had a Narco radio go bad in one of the Archers. Pulled it, sent it to Narco for repair (they don't let anyone else fix their stuff), and it took 13 months, IIRC, before we had it back. Never again. :mad:

Sorry I can't be of more help.
 
Sounds like the blind encoder is going out. Take it to an avionics shop and have a bench check performed on the system, both encoder and transponder.

Blind encoders aren't that expensive to replace.
 
Sounds like the encoder or wiring. I'd check there first. Find an honest avionics shop and have 'em check it.
 
Never forget "Shook's Law"- if it's Narco, throw it out! :D

---

Now that we have THAT out of the way, you can look at the other advice, which references the encoder and its connection (which are almost certainly not Narco at all). Do you recall whether the encoder was replaced when you replaced the old ARC transponder? Fact is, you probably have a 20+ year-old encoder, along with the connectors of similar age, and one intermittent connection can cause a problem such as that you have described.

If you are feeling bold, you might even try removing the transponder and cleaning the contacts while also inspecting for obvious damage and/or foreign objects (bugs, boogers, chunks of old insulation, whatever).

Edit:

PS- My Narco Mark 12D Nav/Com continues to work just fine...
 
Never forget "Shook's Law"- if it's Narco, throw it out! :D

Darn skippy!

PS- My Narco Mark 12D Nav/Com continues to work just fine...

Spike, I think we need Jesse to write a macro - As soon as anyone posts something with "Narco" in the body, it would auto-generate a post from me bitching about Narco, and a post from you continuing to say yours works fine. :rofl:

Our Narco worked just fine... Until it didn't. And then it was a big pain in the butt. I hope yours continues to work just fine... :yes:
 
Kent, I'd dearly love an excuse to buy a shiny, new SL-30...

...what I'd REALLY like, would be for Narco to change hands or turn over a new leaf, start to develop new products and a new attitude for customer service, and provide some freakin' competition in the marketplace!
 
...what I'd REALLY like, would be for Narco to change hands or turn over a new leaf, start to develop new products and a new attitude for customer service, and provide some freakin' competition in the marketplace!

But then I couldn't bust a gut laughing at them when they show up to trade shows to "show off" their amber-display MK 12D's! BWahahahahahahahaa!!!! :rofl: :rofl: :rofl:
 
I used to have Narco stuff.radios are good but the transponders could be better.consider a KT-76A..pretty bullet proof in terms of reliability
 
As a few others have said.. this is more likely an encoder or connection problem, not the transponder itself.
 
Necro post

I'm having issues with the AT165 in our plane. I operate out of a trsa have had spotty issues with them losing us on radar here and there. It checked out fine when doing the IFR check in Feb. Went to take my instrument check ride today at a class c airport 45 miles away from home, worked ok going in, upon climb out with dpe no luck picking us up. Tried resetting etc no luck either. Had to call off the ride. Get in to check it out Monday I guess. Tower said they caught a glimpse of us on radar when we touched down but nothing else. Flew it home they couldn't see me at all. Frustrating
 
I just had my AT-155 repaired for $289.00 and 4 days downtime @
Flight Control Services in Milton, FL.
Dave
 
For what it's worth, Narco going out of business is a good thing - Now, any good avionics shop with component-level repair expertise can fix Narco stuff whereas before you had to send it to Narco and wait an eternity for them to fix it.

Of course, with a transponder, the other thing to consider is ADS-B equipage. You may want to consider just doing whatever you're planning to do for the ADS-B mandate now, as long as your plan didn't involve keeping your now-unreliable transponder! Personally, I'm looking hard at the L-3 Lynx NGT-9000 which is itself a transponder.
 
Might as well get ADS-B now for $500 more (or less) instead of fixing. Of course if this is the encoder, you will need a new one. But for now her is how I got ADDS B Out installed for $2,435

I have ADS-B in via a Gamin GDL 39 and Area 796. All I needed was ADS-B out to be legal. Appareo makes an all in one box (the Stratus ESG ADS-B Out and WAAS GPS) for only $2,995. Size-wise this is a replacement for most King and Narco transponders. I had a Narco AT-165 that was about 10 years old.

I emailed all the shops with 250 miles of my home base (KLVK) and found one that had a reasonable price for the install. Based on my research this only involved adding a tray, GPS antenna and re-pinning the connector. Far less work than a UAT 978 install. Shops up and down the state were coming in around $1,100 to $1,500 for the install.

Airtoroncs in Jackson CA called me about an hour after they got my email. After asking a few questions this shop made a firm quote over the phone for 6 hrs labor at $90 hr for the install, $540 total. It's really not that difficult to install a Stratus ESG. Pull the tray, re-pin the connector, mount the antenna, configure using the menus and ground test. It was a 30 minute flight to Jackson California for the install. Arrived early in the morning, done the same day.

Here is something I did not expect. Airtronics paid me $600 for my Narco AT165. That was more than fair. Apparently there is a very healthy secondary market right now for our used transponders in countries that do not require ADS-B. Airtronics has a relationship with an exporter. This is a unique situation that is not going to last when tons of transponders start to get replaced as we near 2020. Even more reason to upgrade now. I believe if you wait supply and demand, will make your existing transponder worth less a trade-in.

Another reason to do this now. We are talking about 1090 ES. My read on was 1090 ES is that it was kind of "reserved" for the big metal. GA was supposed to install the "lower cost" UAT 978 units. Well the increased cost of installing a 978 solution does not makes sense when compared to the lower cost of installing the Stratus and even the Garmin 1090 units in most GA aircraft. Also, you can't fly to Mexico or Canada (Belize or anywhere else for that matter) without 1090 ES. So in my opinion it won’t be long that the 1090 band gets congested and the FAA comes down with a directive around to save the band for the the jets and and carriers flying over 10,000 ft. routinely. I believe getting 1090 ES now might make sense.

Here is another cost savings hint. There was no need for a replacement transponder antenna. My spike antenna was fine. Many of the shops I contacted up and down the state insisted on installing a dual band "shark-fin" dual antenna for an additional $250. This is not necessary. If you are receiving ADS-B In via another device (i.e. Garmin GDL 39) there is no need for the dual band antenna. The Stratus ADS-B OUT is 1090 only. The unit is not going to receive ADS-B IN and there is no need to waste the money on a new antenna. My advice is to move on to another shop if they insist on installing the dual band antenna for ADS-B OUT only.

Here is another cost savings. Appero includes the external WAAS GPS antenna in the $2,995 price. I had mine mounted foot behind the rear window on my Cessna 182. Garmin's all-in one transponder looks competitive until you find out they don't include the GPS antenna. That is an additional $895. And Garmin is insisting on a dual band antenna transponder antenna even if you don't need ADS-B in. Another $250.

To get the $500 rebate you will need to fly for an hour. Yes, you must do the four 360 degree turns and the 90 degree crossing. The climbs and descents will occur naturally. A quick flight for 30 minutes did not cut it the first time I tried to certify. I recommend you fly slowly for an hour above 7,500 ft and do all the maneuvers required.

I did not certify within the airspace that you are required to have ADS-B. I was in class E airspace at 8,500 feet flying from Livermore CA to Willows CA. I had an excellent controller at Travis Air Force Base work with me to handle the maneuvers. I let her know what I was doing and she was extremely helpful. Trying to accomplish this within the Mode-C veil seemed a bit cumbersome given all the Class B airspace I would have to avoid. We need to clear this myth up. You do not have to certify within the airspace ADS-B is required. At least that was my experience.

After a hour and 10 minutes I landed in Willows CA. I waited 20 minutes and submitted my ADS-B Performance Report request via my iPhone. Then I sat back and enjoyed an excellent lunch at Nancy's Airport Cafe. About 25 minutes later I checked my email and I had my sold four GREEN bars on the ADS-B performance report along with the incentive code required to claim my FAA rebate.

SUMMARY:

Stratus ESG $2,995

Install $540

Trade-in $-600

Rebate $-500

Out of pocket cost (minus taxes) - $2,435

Cost of a new Mode-C transponder is $1,900 without installation. So if you are in need of a transponder now, shell out another $500 bucks, find an honest installer, and become compliant. I was tempted to go with Garmin but I would have spent more. $634 for the WAAS GPS antenna and $250 for the dual band out antenna. $884 savings with Stratus ESG. I say go for it while the FAA Rebate and the value of your trade-in is still high.


Larry Putnam
 
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