Avionics questions

Don't discount a used 530W when searching for a used Garmin. :D Lots of people replacing 430's, but a lot of those same people are replacing 530's at the same time. Keep on ARC nav/com installed and the other for a spare, you'll need it eventually.:D I did that way back in the day with my first 182, it had RT422's ?, they we oddball even by ARC standards. :mad2: I installed a 12D in the number one slot, kept the old radio and I would swap it out when the plastic gears broke in the number two radio, and send the other one out for repair. :rolleyes:
 
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Ron Levy said:
You gain a digital flip-flop radio that works much better than the old mechanically-tuned transistorized unit.
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When the ARC is working, it's working, and will do the job just as well as any other radio.

Nothing is changed except the way it looks.

when the ARC quits, change it out to the MX 300 is the cheapest way to fix it. But be certain its the radio, not the head, because the head is as bad as the radios. and not as easy to change, they are not on the PM list, it requires an authorized person to change them.
 
Tom-D said:
When the ARC is working, it's working, and will do the job just as well as any other radio.
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No, it won't. It's mechanically tuned, has no flip-flop, worse transmission and reception quality, and less accurate squelch. A modern, solid-state, digital radio is significantly superior.
 
We have a TKM MX 300 slide-in replacement in our airplane. I used to have KX-155's. The TKM radio works a little different, but similar. For my money, I wouldn't pay any difference to have the KX-155. I think the TKM radio is just as good.

Garmin has stopped making the 430's (I believe), if that matters to you. I have read that they plan to continue to support them for awhile though. The FAA is planning to decommission a lot of the VOR's fairly soon. For serious IFR, if I were in your shoes, I would go with an approach certified, WAAS GPS. Otherwise, you will be spending quite a bit of money for equipment which will soon be outdated. The GPS units require database updates, which are not free, but the future is going to be GPS so you may as well bite the bullet now.
 
Ron Levy said:
No, it won't. It's mechanically tuned, has no flip-flop, worse transmission and reception quality, and less accurate squelch. A modern, solid-state, digital radio is significantly superior.
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yep, it's a different radio, But the ARC will do the job for 1200 bucks less than the MX. if ya can't hear, it turn the volume up.
 
Define "fairly soon."
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I cannot remember the timeframe. You are probably right with 15 years. My point was that our old nav equipment is on the way out and if a person is spending the money to put in new radios, IMHO they might as well go with GPS. However, if the old equipment works okay, I would not replace it until I had to.
 
We still haven't decided what to do. New question: The 177 has a functional 200A Navomatic auto pilot. If we make any changes to the radio stack, will still be able to get the auto pilot to work? In other words, can we get a new garmin radio to talk to the old autopilot?
 
PPC1052 said:
New question: The 177 has a functional 200A Navomatic auto pilot. If we make any changes to the radio stack, will still be able to get the auto pilot to work? In other words, can we get a new garmin radio to talk to the old autopilot?
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Maybe, maybe not. Depends on which Garmin and what you want the integrated system to do. The next question would be whether there's a GPSS roll steering adapter which works with the Nav-o-matic 200A, and I don't know the answer to that one.
 
Ron Levy said:
Maybe, maybe not. Depends on which Garmin and what you want the integrated system to do. The next question would be whether there's a GPSS roll steering adapter which works with the Nav-o-matic 200A, and I don't know the answer to that one.
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I have hunted for that and not found one. The 200 uses voltages from the turn coordinator and is little more than a smart wing-leveler even though it'll do VOR/ILS "capture". I assume it is stealing voltages for the CDI head for that.

There were far more 300s than 200s produced and there's not much out there for the 300. The 300 had a heading bug which is usually the input of choice for GPSS designers.

Electrically, there doesn't seem to be much barrier to creating a GPSS box to feed fake TC voltages to the AP but the hard part is in integrating the TC voltages so it knows what to send to the (rather dumb) AP. And building in ways to calibrate it to the flakey 200/300. (See below article about the system being "matched".)

A good algorithm in a GPSS black box would go a long way toward making a 200 or 300 actually fly well, though. It'd make a fine (if not very old technology) "dumb muscle" interface to the flight controls if it had a modern computer brain.

Since the TC will wobble back and forth in cruise in bumps, the AP does an excellent job of flying S-turns along a course. :) Dampening that in a GPSS box would be easy.

Not sure there is a market for it though. When 200s/300s die, they're usually not worth fixing. A good old school avionics guy good with discrete components can whip them back into shape, but at a high labor hour/shop cost.

S-Tec was once the way to go to replace them, but they've gotten awfully proud of their boxes either due to product liability or lack of any real competition in the Certified market. Probably both. Technically they're still the way to go, because they're the only way to go. The cost barrier to entry is so high that it's unlikely anyone else will be building for Cessnas. (I'd love to be wrong about that.)

This article details a lot of the wonkiness of the 300. The 200 is the same but missing the heading input from an appropriately heading-bug equipped DG.

http://www.mtnflyers.com/assets/Cessna_ARC_Navomatic_300a_Blue_Highlight.pdf

Not high-tech, but never seen a working GPSS hooked to one either. Would be nice.
 
Is now a good time to upgrade with ADS-B looming on the horizon?
 
Ron Levy said:
The real question is whether the airports to which you would expect to want to fly have enough VOR/LOC/ILS approaches that don't require ADF (or GPS as a sub for ADF) for you to be comfortable without GPS (especially since the ADF is dead already). Talk that over with your partners; if they are already instrument rated, they should be able to give some insight.
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You are going to need either an ADF or DME to get any real use of the airplane if it does not have an IFR GPS. The airplane I fly has none of these things, and if I just had an adf or dme It would open up a ton of approaches to me.
 
PPC1052 said:
I talked to one of my partners about the Michel TKM MX 300 radios. We are going to try to get some information about them from a avionics specialist to see what his opinions of them are.

Have any of you all used them? What are your thoughts? Are they decent? Would we be happier with the Narco verison designed to fit the same tray?
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These radios are in three different aircraft that I fly regularly and I find they work very well. They're simple and flip flop, thats all you really need.
 
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I'm considering similar for my 1974 177B. I currently have a KX-155 and MX-300 navcoms, a Garmin 320 transponder, and the original ARC ADF and Navomatic 300 autopilot (both actually still work!) For an audio panel, I have Cessna's original installation, consisting of a set of toggle switches in the instrument panel.

The plan is to pull the MX-300 and ADF, demote the KX-155 to Nav #2, and put in either a GTN 650 or 750, with a PS8000 audio panel. The quote from the local avionics shop was in the $22k range (for the GTN 750 option)

My transponder currently lives in the right side of the panel, under the glove compartment. I would like to move it to the center stack, but I've measured and it won't fit if I go with the GTN 750.

PPC1052 said:
I recently purchased a 1/3 part of a 1976 Cessna 177B. It has the original avionics, although it is IFR rated. We are looking to upgrade, but have yet to decide what to do. Maintaining IFR rating is mandatory for us. It's in the partnership agreement.

We could go with all new, with the latest and greatest (newest garmin touch screen GPS) for about 30k installed. The downside is, obviously, the cost.
We could try to go used. Just looking for dual nav/coms, with indicators, glide slope, audio panel, mode S transponder (all bendix/king), with a blind encoder, looks like it would be right around 10k just for the equipment, and I have no idea what it would cost to install. I think I could upgrade one of the nav/coms to something like a used garmin 430 for an additional 4k (or 6k for waas, if available).

I would really like to give myself a good general education about all these issues so I can make an educated decision about which way to go. Is there some resource that I can use to help educate myself about avionics, which models/brands are good, compatibility issues, what all the requirements are to make the system functional, etc.?

Because the cost would be split three ways, it may be that it is worth it to us individually to buy a little more functionality, even if the total package cost would seem unreasonable relative to the airframe. For example, if an all used system installed is 15k, my share is 5k, but if the total cost is 30k, my share is 10k. Maybe it would be worth it to each of us to spend that extra 5k to get the upgraded functionality. On the other hand, it is still 5k.

What do you guys think about which way to you would go, and why?
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Okay, we still haven't pulled the trigger on anything yet. We may just need to replace the audio panel. We may try to just find a used original ARC audio that will still operate the 200A autopilot. Any ideas where I can find the part number? I checked the POH, and all I can find is the part number for the marker beacon, but I don't think that is what I need.
 
Mike5250 said:
Can the new touch screen do anything the 430 can't ? The 430 seems like a proven piece of equipment. Also, a lot more pilots you fly with will know the 430 and how to use it.
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HELL YES!!! Holy crap, where do you want to start? Intuitive menus to being able to 'rubber band' amendments to your clearance, it's a much better box.
 
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