Need to Replace Transponder: What to do??

[somorris]

Hey Jose.

If I were in your position, I would just replace the Mode C altitude sender unit. In our airplane, it was separate from the transponder, and cost between $200 and $300 to replace. Took less than an hour for the replacement and the transponder check. That would give you a little breathing room .

 

[JoseCuervo]

I don't think that Mode S is required in 2002 unless you want to fly in Class A.

A worn out mode a/c transponder can be replaced with a new mode a/c transponder, and the ads-b out requirement met with a UAT box like the Garmin GDL-88 connected to a WAAS GPS.

Does it then make sense to use a Mode A/C transponder like Jay's for the next 5 years, then worry about the upgrade to the 430 and a box (of some sort) for UAT at a later date, when there might be more products and options?

 

[JoseCuervo]

Hey Jose.

If I were in your position, I would just replace the Mode C altitude sender unit. In our airplane, it was separate from the transponder, and cost between $200 and $300 to replace. Took less than an hour for the replacement and the transponder check. That would give you a little breathing room .

I think the current/old transponder (Cessna 300 series) needs to go. The switches/knobs don't really have good accuracy, you sometimes have to "twittle" with the 3rd knob to get the right number to transmit. The power/sby/On/Alt knob spins all around... The faceplate is held by one screw.... etc...

The mechanic, when buying the plane, advised the first thing to spend money on was getting rid of the "piece of ****", and 3rd flight had the fuse blow. The Avionics tech I took it to for the fuse didnt' charge me to pull the unit, replace fuse, test and install, but he kind of told me that he really didn't want to see it again, that I needed to begin the upgrade process.

Now, ATC tells me they aren't getting altitude.

The current one is a piece of crap, needs to go.

 

[Neal Howard]

I fully intend to continue running a mode-C transponder and add on some sort of UAT box when it becomes necessary. I have no need or desire to install a mode-S/1090ES transponder since the highest I'll ever be going in my little airplane is probably 14500 when crossing the Rockies.


I'd recommend just finding the best deal you can on a used transponder. The Garmin GTX-320A, if you can find one, still has the knobs to turn, and is solid-state so no cavity tube to wear out. The King KT-76A still has a tube, I have one in my plane and it works fine and I'll run it until the day it dies. If Jay will give you a good deal on his old one that may be a good course of action. Of course you'll have to pay a shop to wire in a different tray.

The cheapest thing to do would be just find a good used Cessna/ARC/Sperry RT-3xx as a slide-in replacement.

 

[poadeleted20]

I wouldn't be advising to use a mode S transponder in the first instance as the means of complying with the 2020 mandate.

Even if you were, a Mode 3A/C transponder wouldn't be the single-box answer anyway.

 

[poadeleted20]

I don't think that Mode S is required in 2002 unless you want to fly in Class A.

...or internationally where ADS-B is required (976 UAT being a US-only option), but I'm not sure where that is. And I'm sure you meant 2020, not 2002.

A worn out mode a/c transponder can be replaced with a new mode a/c transponder, and the ads-b out requirement met with a UAT box like the Garmin GDL-88 connected to a WAAS GPS.

I do believe there is an internal SBAS/WAAS GPS option for the GDL-88 (like $1000 extra?), negating the need for an independent WAAS GPS unit.

 

[poadeleted20]

At this point, I will always be VFR, perhaps marginal VFR, or even "VFR not recommended", but no plans to be IFR.

I have a Class C about 30 miles away, sometimes need to cut thru it, sometimes will likely need to go there for service or pick up somebody at the bigger airport.

I have been flying into SF Bay area airports, avoiding the Class B, but definitely crossing thru other airspaces.

What do you suggest my 2014-2019 solution?

and a 2020 solution?

I suggest you look at this as a modular or upgrade path. Assuming you don't want to have to phone ahead for transit approval through that C-space every time, you're going to need an ADS-B out capability as well as a new Mode 3A/C transponder. The only question is what best fits your needs and budget. My thought is that going with a simple Mode 3A/C transponder now and a 976 UAT box later is probably your simplest and least expensive option.

Which transponder? Since what you have is an old Cessna ARC 300-series unit, there's no getting away from a full install with tray and wiring as you could with some of the newer drop-in replacements from Bendix/King for their earlier models. The GTX327 is a pretty good choice, as Garmin equipment is high quality and reliable. The cheaper Trig units are getting a lot of talk, but IMO the Garmins are a more proven product.

Which 976 UAT box? I'd wait and see what develops in the next couple of years, but remember that they aren't going to be able to manufacture and install 100,000 ADS-B units in 6 months, so I wouldn't wait until summer 2019 (or even summer 2018) to make a choice. In any event, if you do not have (and don't plan to get) a WAAS GPS like a Garmin 430W or 650, you can get one of the UAT units with an internal GPS chip, but if you do, that's one less feature you'd need from your UAT box.

 

[poadeleted20]

Does it then make sense to use a Mode A/C transponder like Jay's for the next 5 years, then worry about the upgrade to the 430 and a box (of some sort) for UAT at a later date, when there might be more products and options?

You're still going to need a Mode 3A/C transponder to provide data to the ADS-B-out unit, so there's no getting away from fixing that problem, and you might as well get a good one now that will work for you through the 20's and beyond.

 

[John Collins]

I'm just going to part my plane out when the mandate comes. It's going to demolish the value if I don't upgrade to ADS-B, yet at the same time I am not dumping more than what the plane is currently worth into it to keep it IFR legal.

The mandate is not for IFR.

It is for access to airspace, VFR or IFR. IFR is still available without an ADS-B unit as long as you do not go into the airspace.

It is an airspace equipage rule.

 

[John Collins]

Does it then make sense to use a Mode A/C transponder like Jay's for the next 5 years, then worry about the upgrade to the 430 and a box (of some sort) for UAT at a later date, when there might be more products and options?

Yes. Buy a good mode A/C transponder. Garmin is not the only game in town and is generally more expensive than its competitors. Look at the Sandia STX 165.

 

[John Collins]

Even if you were, a Mode 3A/C transponder wouldn't be the single-box answer anyway.

It would to the Op's question and title of this thread.

 

[John Collins]

...or internationally where ADS-B is required (976 UAT being a US-only option), but I'm not sure where that is.

Ron you keep bringing up the international canard, and I keep shooting it down. Read one of my numerous posts on what the international community is actually requiring.

 

[Pedals2Paddles]

You could just save your AMUs for now. Buy a used or refurbed Mode C unit. Spend way less than a $1000 on a used unit including install. You do not need anything new. Mode C today is the same as it was 20 years ago, and the same as it will be in 2020, 2025, etc etc.

Development of the portable and modular UAT boxes is really taking off. The next 2-3 years will likely see lots of really great things as well as a lower price. You can get a better, more complete, and probably less expensive UAT box in 2-3 years in preparation for 2020.

 

[txflyer]

So what about the position source?

Ugh, I didn't think about that.

It would work for ADS-B out, but not without a 430W or similar GPS. Then I guess you would still need a UAT box to make it all work.... I'm confused at the moment ... I'm going to hold off until later in the game and just use portable ADS-B and my old PCAS system for now.

The new Lynx box mentioned before may be the solution to those of us with a 430W and a mode-C transponder in our panel now. You need a bluetooth connection to a iPad or portable device to display weather and traffic or SVT. The older 430's and 530's can't display and use all the info like an iPad or 796 can.

 

[Neal Howard]

The new Lynx box mentioned before may be the solution to those of us with a 430W and a mode-C transponder in our panel now. You need a bluetooth connection to a iPad or portable device to display weather and traffic or SVT.

You could also use your existing 430W as a certified GPS position source for the cheaper of the two NavWorx UAT boxes available today, the ADS600-B, the one that contains a built-in, but non-certified GPS, but can also accept data from an external certified GPS instead, which is currently selling at the "Oshkosh special" price of $2399 (don't know how long that will last). That UAT is TSO'ed for its ADS-B OUT function and also now STC'ed with an AML for installation in certificated aircraft.

BTW, I was mistaken about the upcoming L-3 Lynx having Bluetooth for wireless transmitting of traffic and weather data to a tablet, it also uses WiFi instead of Bluetooth for wirelessly getting that data to external devices, according to the brochure available here: https://www.l-3avionics.com/media/37006/lynx-flyer.pdf

 

[John Collins]

You could also use your existing 430W as a certified GPS position source for the cheaper of the two NavWorx UAT boxes available today, the ADS600-B, the one that contains a built-in, but non-certified GPS, but can also accept data from an external certified GPS instead, which is currently selling at the "Oshkosh special" price of $2399 (don't know how long that will last). That UAT is TSO'ed for its ADS-B OUT function and also now STC'ed with an AML for installation in certificated aircraft.

The NavWorx UAT is not approved to use the GNS430W as a position source. I suspect that they will eventually remedy this as they were told by their ACO it was not permitted to use reverse engineering the Garmin and use it as a position source, but now that Trig has accomplished exactly that, the ACO has some splaining to do.

 

[Pedals2Paddles]

Things like this are why I suggest waiting 1-2 years. There will be so many options, tried and tested, by then. Just get a cheap refurbed or even cheaper tested used Mode C transponder for now. Worry about a UAT for ADS-B once things settle down.

 

[txflyer]

In the meantime, there is no full coverage with only ADS-B in. You still have to run PCAS if you want to paint all the transponder codes around you. And the weather kind of sucks compared to XM. You can't get weather sometimes on the ground with ADS-B. And it's slower painted weather.

The only thing real promising about ADS-B is the traffic, but you need a $5000.00 box for it to MAYBE work and show you all the targets. I'm holding off until the last second or until somebody get's their **** together.

Thank you government. You make things so simple, inexpensive, and easy.

 

[Neal Howard]

The NavWorx UAT is not approved to use the GNS430W as a position source. I suspect that they will eventually remedy this as they were told by their ACO it was not permitted to use reverse engineering the Garmin and use it as a position source, but now that Trig has accomplished exactly that, the ACO has some splaining to do.

Interesting... I was under the impression that Garmin now had a firmware update to fix the issues that late last year stopped the 430W from being a rule-compliant position source for ADS-B OUT.

Did they implement the fix in some manner that resulted in only other Garmin products (which could speak a secret proprietary protocol amongst themselves) would be able to work together?... and Trig reverse engineered that?

 

[John Collins]

Interesting... I was under the impression that Garmin now had a firmware update to fix the issues that late last year stopped the 430W from being a rule-compliant position source for ADS-B OUT.

Did they implement the fix in some manner that resulted in only other Garmin products (which could speak a secret proprietary protocol amongst themselves) would be able to work together?... and Trig reverse engineered that?

Garmin has never publicly disclosed its ADS-B position source interfaces or for that matter its ADS-B In interface to display weather and traffic. The only exception to this I believe that Garmin licensed FreeFlight to use the protocol with their 1201 position source so it could drive the Garmin GTX330ES in some installations.

The GNS430W has had a serial interface to its GDL90 and GTX330ES version 1 for quite some time. Trig reverse engineered it and was expected to announce an STC back in 2013 at Oshkosh. Several months before that point, Garmin came out with a notice and service bulletin that said the ADS-B position source interface was not in compliance with the 2020 mandate. Garmin then added a new choice ADSB + that did comply and their GTX330ES with version 2 and the GDL88 support this interface. It requires later versions of software for the GTX330ES and the GNS. Trig reverse engineered it as well and has completing testing and announced they have their STC. According to them, it will be available in a new Trig software release and STC package in the next week or so, so those with a Trig and the GNS will be able to work together.

 

[John Collins]

In the meantime, there is no full coverage with only ADS-B in. You still have to run PCAS if you want to paint all the transponder codes around you. And the weather kind of sucks compared to XM. You can't get weather sometimes on the ground with ADS-B. And it's slower painted weather.

The only thing real promising about ADS-B is the traffic, but you need a $5000.00 box for it to MAYBE work and show you all the targets. I'm holding off until the last second or until somebody get's their **** together.

Thank you government. You make things so simple, inexpensive, and easy.

I agree with your observations except for "And it's slower painted weather." The update rate for the regional NEXRAD is every 2 and 1/2 minutes as compared with the XM update rate of once every 5 minutes. This only affects the initial screen because the latency to receiving data is shorter, but the update for the data is the same at the source.

 

[txflyer]

I agree with your observations except for "And it's slower painted weather." The update rate for the regional NEXRAD is every 2 and 1/2 minutes as compared with the XM update rate of once every 5 minutes. This only affects the initial screen because the latency to receiving data is shorter, but the update for the data is the same at the source.

Well if you're on the ground, ADS-B may not be painting at all, so that's slower.

The rub is, there's a big rub with ADS-B. You can't have it all. And for what they're charging for all this new stuff, you still can't have it all. Even with the latest greatest stuff, you still can't paint weather on the ground like XM.

My 496 used to go everywhere with me. It navigated streets and had weather and metar's all the time through the XM. I could be looking at the NEXRAD along my route of flight while on my way to the airport in the car. ~$2000.00 later, after a GDL39 and a 696 and all the BS that goes with it, I'd be happier if I had just stuck with my old 496 with XM and my PCAS and saved my money. $2K would have paid for over four years of XM fees.

 

[jesse]

Well if you're on the ground, ADS-B may not be painting at all, so that's slower.

The rub is, there's a big rub with ADS-B. You can't have it all. And for what they're charging for all this new stuff, you still can't have it all. Even with the latest greatest stuff, you still can't paint weather on the ground like XM.

My 496 used to go everywhere with me. It navigated streets and had weather and metar's all the time through the XM. I could be looking at the NEXRAD along my route of flight while on my way to the airport in the car. ~$2000.00 later, after a GDL39 and a 696 and all the BS that goes with it, I'd be happier if I had just stuck with my old 496 with XM and my PCAS and saved my money. $2K would have paid for over four years of XM fees.

It's incredibly rare that I can't get a strong enough Verizon signal to paint weather on my iPad on the ground.

 

[txflyer]

It's incredibly rare that I can't get a strong enough Verizon signal to paint weather on my iPad on the ground.

XM was rock solid is all I was sayin. On the ground and in the air.

I expected great things out of the GDL39, but so far, it's been a let down. The traffic function you might as well say is useless without ADS-B out, and it's propietary architecture makes it really finicky with bluetoothing or open sourcing to anything. The whole thing stinks of milking every solitary dime out of pilots for a product that works half-ass and I don't like that. I gave up on trusting any bluetooth connection and bought a hardwire to my 696.

I would leave Garmin so fast it would make their head spin if a competitor could come in and bust their balls on some things. Especially the Jepp updates. I'm not brand loyal as you can probably tell.

 

[Jay Honeck]

Well if you're on the ground, ADS-B may not be painting at all, so that's slower.

The rub is, there's a big rub with ADS-B. You can't have it all. And for what they're charging for all this new stuff, you still can't have it all. Even with the latest greatest stuff, you still can't paint weather on the ground like XM.

Just one data point: I receive ADS-B radar on the ground inside my hangar. It all comes down to your proximity to a ground station.

Here's the solution I went with in our panel upgrade last February:

1. Display: GRT Horizon HXr, 10.5" EFIS

2. ADS-B Out: Trig TT-22 Mode S transponder/ADS-B

3. ADS-B In: SkyRadar DX

After six months, I can report that radar has been near-100%. We received it from the Gulf to OSH and back.

Traffic has been sporadic but improving.

We also run the GDL-39/Nexus 7 tablet ADS-B combo, and that device, with that receiver, is equal to (and sometimes superior) to my in-panel solution. It doesn't offer ADS-B OUT, of course.

Here's a couple of views of what traffic looks like:

And here is what weather looks like, on another screen set up. (The HXr allows you to change the screen set up in many ways.)

It's a brave, new world, kids.

 

[dans2992]

Jay,

With ADS-B out, shouldn't you be seeing _all_ the traffic? The ADSB ground stations re-broadcast anything on ATC radar (even Mode C) don't they?

 

[John Collins]

Jay,

With ADS-B out, shouldn't you be seeing _all_ the traffic? The ADSB ground stations re-broadcast anything on ATC radar (even Mode C) don't they?

You should be able to see most of the nearby traffic as long as several conditions are met.

1) The target has to be in radar coverage for Mode A/C targets.
2) You must be within the service limits of the GBT (Ground Based Transceiver)
3) If the target is within the service limits of the GBT TISB service and you are line of sight to the GBT and the target is within your hockey puck of airspace (+/- 3500 feet and 15 NM radius of your position), then the GBT will generate the TISB target on your behalf.
4) The TISB service has to be working in the GBT and radar service has to be working as well. If either is OOS, then you will get nothing, even though your equipment is working just fine.

If the target aircraft is also equipped with ADS-B out on a frequency you can receive, then you don't need any of the ground based systems to be operating. If you have a single frequency receiver and have your ADS-B Out set up to indicate your receiver capability, then you are dependent on the GBT to rebroadcast the target's position data on the frequency you can receive.

So for example if radar coverage is down to 2000 feet AGL in your area, and line of sight to the GBT is at 4000 AGL, you won't be able to see traffic below 4000 AGL. For most enroute flying traffic aught to be pretty good.

In spite of all this, the service seems to be reliable especially during the enroute phase of flight, but it is still far from being an equivalent of an active TAS or TCAS system, particularly in the pattern and mountainous areas.

 

[Jay Honeck]

Jay,

With ADS-B out, shouldn't you be seeing _all_ the traffic? The ADSB ground stations re-broadcast anything on ATC radar (even Mode C) don't they?

In theory, yes.

In practice, we have lots of problems.

1. Insufficient ground stations. This is improving.

2. Insufficient problem reporting. There is no easy way to find out if a ground station (or stations) are functioning, or if they are down.

3. ATC doesn't know or care about any of it. If you ask them if there's a problem in a given ADS-B sector, they have no clue.

Apparently Flight Service (remember them?) has been given responsibility for maintaining PIREPs about ADS-B coverage. Which means, of course, no one says or knows nuthin'.

Bottom line: It's just another ginormously wasteful and stupid government program, not unlike Obamacare, with little accountability and no way to discern fault or blame when the system doesn't work.

Our only hope is that this improves over time. Right now, the weather reporting is great, and "free", and traffic reporting along the Texas coast near Corpus Christi is getting more reliable every day.

Everything else is a wild card, for now.

 

[txflyer]

Bottom line is, even with $10K or more of stuff, you still will not paint all the targets, and you may not get weather.

My little $1200 Zaon PCAS shows everything within 5 miles. XM is rock solid.

Get flight following, and you've got it covered.

 

[Jay Honeck]

Bottom line is, even with $10K or more of stuff, you still will not paint all the targets, and you may not get weather.

My little $1200 Zaon PCAS shows everything within 5 miles. XM is rock solid.

Get flight following, and you've got it covered.

For now, if you're on a budget, that's the way to go.

On the other hand, ADS-B improves every day. Heck, traffic display has improved markedly down here on the coast just since we left for Oshkosh last month!

Eventually, they will get it nailed down.

 

[txflyer]

For now, if you're on a budget, that's the way to go.

On the other hand, ADS-B improves every day. Heck, traffic display has improved markedly down here on the coast just since we left for Oshkosh last month!

Eventually, they will get it nailed down.

If GP comes out with SVT for android, I'll get a 3D GDL39. But until then, I'm sticking with old tech and saving my $$$$. SVT is wonderful.

Still, nothing beats LOOKING outside.

PCAS and ADS-B will not catch that Mooney that's closing on you if he forgot to turn on his ALT on his transponder. I've had that happen on flight following and ATC never uttered a word as the guy zipped below us on an opposite heading. Thank God he was at least observing altitudes albeit loosely. He was 500' below us, so he should have been IFR and being tracked. But I think he was just flying.

 

[Jay Honeck]

If GP comes out with SVT for android, I'll get a 3D GDL39. But until then, I'm sticking with old tech and saving my $$$$. SVT is wonderful.

Still, nothing beats LOOKING outside.

PCAS and ADS-B will not catch that Mooney that's closing on you if he forgot to turn on his ALT on his transponder. I've had that happen on flight following and ATC never uttered a word as the guy zipped below us on an opposite heading. Thank God he was at least observing altitudes albeit loosely. He was 500' below us, so he should have been IFR and being tracked. But I think he was just flying.

I will say this: I don't miss giving XM $60/month.

 

[txflyer]

I will say this: I don't miss giving XM $60/month.

I don't pay them anymore either, but I do miss the XM. I don't trust ADS-B yet.

Trust is the lifeblood of a pilot.

What makes ADS-B tolerable is all the other apps I have for weather on my phone that I use to verify what ADS won't tell me before I take off.

 

[coloradobluesky]

Does ADSB out show up on TCAS?

 

[Jay Honeck]

I don't pay them anymore either, but I do miss the XM. I don't trust ADS-B yet.

Trust is the lifeblood of a pilot.

What makes ADS-B tolerable is all the other apps I have for weather on my phone that I use to verify what ADS won't tell me before I take off.

I'll tell you what: When it's working, ADS-B is amazing.

Example: We came back to the island yesterday, and had the skydive jump plane, a Navy trainer, and a silent target going down the beach, all depicted on our EFIS.

I was high overhead, and watched as the jump plane departed toward the silent target. I was about to say something, when the pilot spotted the silent traffic -- a helicopter buzzing down the beach, right off the departure end of Rwy 12 -- and took a pretty hard, low level evasive turn.

From my vantage point, it looked pretty close. And I saw the guy LONG before the jump plane pilot.

This has happened again and again, to the point where I feel half naked when the traffic depiction isn't working. I will feel a LOT better when (a) the system is fully operational, and (b) when problem reporting is codified and routine, so that we know when a sector is down.

More to your point, the weather seems to be working just fine.

 

[weirdjim]

Bottom line: It's just another ginormously wasteful and stupid government program, not unlike Obamacare,

Buddy, I love you dearly, but could you PLEASE keep your political ravings to a political forum and keep this one to aviation.

THanks,

Jim

 

[John Collins]

Does ADSB out show up on TCAS?

Not with current TCAS, it still depends on the transponder reply. There is an enhancement to TCAS that integrates ADS-B, but I don't know its operational status.

 

[Pedals2Paddles]

TCAS should show anything with a transponder, doesn't it? My understanding is that it is listening to the secondary replies on 1090 to determine radio distance and bearing, and the mode c altitude.