DME makes me cranky

denverpilot

denverpilot

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DenverPilot
Okay, the long and annoying story of the DME.

It's a King KN-62A.

It failed on the way home from Nebraska right after the Instrument checkride. (At least it survived that.)

The Transponder failed at roughly the same time.

We take it to Freedom Avionics at BJC. Requires permission to fly it up there from DEN TRACON for Mode C veil to take a transponderless aircraft across town. Done.

They pull both, Transponder tests fine on the bench, DME won't power up.

Aircraft tested, coax to Transponder antenna has failed shorted. Freedom swaps DME coax over to Transponder to give it a working antenna. Sends us home with new W&B minus 2.4 lbs of DME, so we're legal and we fly some already scheduled flights (my trip to Gaston's).

They call and say DME fixed. It blew a fuse. Bench time charged. Half price on rediculously priced fuse ($27) from King. We retrieve DME and put it back in the tray, swap W&B and it works for one flight.

DME drops out again next flight, no power.

More scheduled trips intervene.

Having read some disenchanted owner stories about Freedo online, we discuss with new Avionics tech at APA. Taking the aircraft across town is a small annoyance.

They say it's likely the display failing since it blows the fuse at power up and a brief flash of the display is seen.

They recommend we change the fuse ourselves again just to make sure, since it's a pilot-accessible item which doesn't require a yellow tag, and they peek around inside the DME for any signs of blown/damaged components and do the old sniff test for burning. Nothing showing.

$27 full-price fuse from a third party parts vendor acquired. And installed.

Avionics master on, fuse sizzles and blows instantly. Damn.

Discussion now ongoing:

- Repair existing DME. Unknown price.

- Buy yellow tagged identical DME and swap in. Perhaps having tray and harness double checked prior to installation. Roughly $2K.

- Bite a big bullet and move the entire stack down, replace #1 OBS, and install Garmin. $6500 for a used 430W minimum, not including installation or #1 OBS.

- If Garmin, decide if dual-ILS capability desired. Move existing #1 OBS w/ glideslope down to #2 hole and keep current #1 Nav/Comm while dropping #2 Nav/Comm and #2 non-glideslope OBS. And remove DME and DME Nav 1/2 switch altogether.

- Or... fix/replace DME AND add Garmin. (unlikely)

The real bummer? Likely we'll have flyable IMC here tomorrow or Thursday.

Can go up /U but once up, can't get back into home base. No approaches into APA that don't require /A or ADF on board. Crud. :(

Could go up anyway and strand the airplane at BJC, FTG, FNL, or GXY and bring it home this weekend.

Seems kinda stupid though. :( :( :(

Thoughts from the peanut gallery?

- Would you risk stuffing a different DME in that tray? (I'm thinking no.)

- Anyone know a great King repair shop? We've got the alternate W&B so tossing this thing in a FedEx box for a solid going-over isn't a problem. Plus if we decided to resell it, it's going to be worthless broken and barely worth anything repaired, I suspect.

- Had a thought a one point that we like the King Comm radios better than we like the Garmin Comm stuff -- they're rare, but the non-Comm version of the 430W might be out there somewhere. Can't quite figure out if that GPS has the Nav ILS/VOR receiver in it or if that's also stripped out from docs I've been looking at. Still means problems for the intercom wiring though, since we'd then have three Nav heads to Ident.

- Resale values. I've looked up some numbers, but what's realistic for a King KN-62A, and/or a King KX-155 w/o glideslope and non-GPS capable OBS? Probably not a lot, but not zero I'm guessing. (I'll have to look up the OBS model number, but it's one model before the one that added the circuitry to interface with King GPS units.)

Just thinking out loud here. Feel free to join the fun. No reasonable thoughts discarded. ;)
 
GNS 430W is GPS/Nav/Comm
GNC 420W is GPS/Comm
GPS 400W is GPS only.

All are officially discontinued by Garmin.
 
murphey said:
GNS 430W is GPS/Nav/Comm
GNC 420W is GPS/Comm
GPS 400W is GPS only.

All are officially discontinued by Garmin.
Click to expand...

Understand they're all discontinued. We're not all that comfortable with touch-screen interfaces. (Two of us generally think they'll be less reliable over the long haul. Maybe even a flat out mistake by Garmin. We can certainly be wrong. Just a preference.)

Thanks for confirmation on the Nav. That's what I thought, but wasn't certain.
 
Last time you posted about your broken arc transponder you got a lot of good advice even though you'd already made up you mind to go the budget route and put in a used one. Why waste more bandwidth with the same questions regarding your similarly out of date DME?
 
AcroBoy said:
Last time you posted about your broken arc transponder you got a lot of good advice even though you'd already made up you mind to go the budget route and put in a used one. Why waste more bandwidth with the same questions regarding your similarly out of date DME?
Click to expand...

There was nothing wrong with the transponder. It was reinstalled. No used transponder was purchased.

The coax to the antenna was shorted.

Coax was re-run and replaced. I was clear about that, both in that thread and even above in THIS thread.

The point of the posts is to double-check that there aren't other options and discuss with other aviators in the community. It is a discussion board after all.

All advice or information is appreciated, and I'm not the only person involved in these decisions on this end, of course. There's three co-owners and their respective families of co-owners here who get priority over any particular advice found on any Internet message board. That shouldn't be any surprise to you or anyone else.

The information garnered from the other thread was useful in confirming that there was little value in upgrading that particular unit prior to finding ours was fine. Didn't matter in the end.

It also clearly brought out that the "well liked" avionics shop had a history of screwing up another PoA member's avionics work, which we didn't quite fully think wasn't a one-time deal at first, but our experience has held that up to also be true. That information in and of itself is valuable, from both threads.

I'm pretty sure I was polite and extended my thanks for the advice given in the other thread. We're you expecting something different?

If you're expecting me (or anyone else) to take Internet advice as gospel on any particular topic, you might end up disappointed. If you find talking about various aviation related avionics topics as "wasted bandwidth", a discussion board may not have been the correct place to be on the Internet?

Lots of folks here say I should build an RV, too. Doesn't mean I have to do it, and typically they aren't angry about it. ;)

Sure is easy to get folks panties in a bunch around here lately. Hope it's just a sign that you had a bad day. Wow. Just wow.
 
murphey said:
GNS 430W is GPS/Nav/Comm
GNC 420W is GPS/Comm
GPS 400W is GPS only.

All are officially discontinued by Garmin.
Click to expand...

Not yet, but it is expected they will be soon. The GNS500W series are discontinued as are the non W versions of the 430/530.
 
It is possible the antenna has a short to ground in it, particularly if it is one of the short wire antennas with the aluminum ball at the end. They break off easy when you are washing the underside of the airplane, usually leaving a mark on your head.
 
To me, it's pretty hard to discount the utility that comes with owning a WAAS GPS if you're planning on flying much (if any) IFR. I put 2.3 hours on under the hood the other day with what I thought was a flaky DG (turns out it was probably a flaky compass). After a while I stopped bothering to reset my DG and just flew most of the flight off of the 430.

What it adds in options (LPV approaches into almost any airport), redundancy and situational awareness is pretty hard to measure. If I were sitting in your shoes and unable to find a simple fix for my DME issue, I'd be pretty tempted to pony up for the 430W.
 
Personally, I'd keep a DME unit. That's with the knowledge I have of just how fragile GPS really is (WAAS included). How far will you be flying from the GPS-denied test zones in various parts of the US?

You can get a replacement for the KN-62 fairly cheap on Fleabay (under $1000 - I think I paid about $700 for one). Remember that it technically requires a sign-off (even for a like-for-like replacement) as the Preventative Maintenance rules exclude DME replacements.

Yes, a WAAS GPS makes a ton of sense given that it's the future and there are a lot of LPV approaches now. That said, when the bits are down, I'd still like a deep backup in the form of DME to go with the ILS......

But hey, that's just me, and I tend to be a bit more conservative than some about these things.
 
Paying good money to repair old "pulse" equipment has always been a fools errand. It was true back in the days when the pulse equipment went from tube to transistor. It is true today as it is being replaced by GPS.
 
I like the King products myself but they are pretty old. I have to wonder at what point it is no longer useful to hold on to the old stuff needing repairs.

Some other avionics manufacturer probably still makes a DME but I am not sure. If I were in your place, I would probably think it is time to upgrade to a newer model (used maybe) if not a brand new in the package unit.

Buying used is always risky but you could go through and avionics shop and have used pieces tested before installation.

Just my .02

David
 
I like DME.

That said, I'd hesitate to spend a raft of money on refitting the existing one. First and foremost, you need a legitimate shop which can well and truly bench-test your 62, see what is up and isolate the problem. Blowing a fuse could very well mean something really simple like a shorted cap or a bad voltage reg chip - but you know all that. Again, so much depends on finding a skilled shop with a true bench tech diagnostician (not just a parts-swapper).

But I'd sure recommend getting a WAAS GPS in any event.
 
Nate,

I have studied the approaches at APA and have a solution for you: install an ADF!!! ;) (This may also be a Bill S. approved belt-and-suspenders method).

If you didn't need DME to get back into your home airport, I'd say ditch it. Since it's always easier to spend other pilots' money, it's hard to argue against some kind of WAAS GPS. $2-$3k per partner - boom - done! And you gain excellent utility.

Do you need a KN-62A? Used/refurbs at the usual avionics shops (i.e. Bennett) peg it around $2500, but the regular KN-62 seems much cheaper as Bill said. I did notice a lower price for a refurbished exchange here:

http://www.sea-avionics.com/lc/cart.php?target=productDetails&model=KN-62A&substring=kn62a

If it is the display (which we can't be sure of), this expired ebay listing was asking $234 for one, which might give you an idea on how much it would be to repair.

http://www.ebay.com/itm/FACTORY-NEW-BENDIX-KING-KN62-KN62A-KN64-DME-DISPLAY-/230807168608
 
SCCutler said:
That said, I'd hesitate to spend a raft of money on refitting the existing one. First and foremost, you need a legitimate shop which can well and truly bench-test your 62, see what is up and isolate the problem. Blowing a fuse could very well mean something really simple like a shorted cap or a bad voltage reg chip - but you know all that. Again, so much depends on finding a skilled shop with a true bench tech diagnostician (not just a parts-swapper).
Click to expand...

This is so true Spike. The sad thing is, Nate (and many of us here) have the know-how to troubleshoot a failing power supply for some hunk o' crap from the 1980's and we're not allowed to.
 
rpadula said:
This is so true Spike. The sad thing is, Nate (and many of us here) have the know-how to troubleshoot a failing power supply for some hunk o' crap from the 1980's and we're not allowed to.
Click to expand...
:yeahthat:
 
Hmmm, sell share in 182 and make outright purchase of a grossly overpriced Frankenkota! 430W, Apen, DME, and autopilot already installed.

You know how I use DME around Denver but the more time I spend with the 430W the less I'm using DME. GPS gives a heck of a lot more capability so I suggest going the 430W route.
 
DME is ok, but all grain brewing is still the way to go :)
 
My 480 was discontinued long ago but Garmin still works on them. Had mine repaired 2 yrs ago. It's not as user friendly as a 430Wbut it still gets the job done. Done several LPV approaches dead on. Database is no longer current so it'll be a while before I fly IFR with it again. They're still a bit pricey on the market though. I'd go with a 430W.
 
The plane I flew across the state this past weekend has both DME and a 430W. As I was flying V routes (mostly) the DME was handy for finding changeover points. And the DME and GPS did NOT agree on the distance, and, yes, I was far enough away that slant range did not matter. Navigated by VOR, kept situational awareness with GPS. The combination is nice to have. Full backup in case one went TU.

I'd keep looking at options to get the DME fixed or replaced.
 
Ghery said:
The plane I flew across the state this past weekend has both DME and a 430W. As I was flying V routes (mostly) the DME was handy for finding changeover points. And the DME and GPS did NOT agree on the distance, and, yes, I was far enough away that slant range did not matter. Navigated by VOR, kept situational awareness with GPS. The combination is nice to have. Full backup in case one went TU.

I'd keep looking at options to get the DME fixed or replaced.
Click to expand...

While they were both probably "accurate enough", I'd bet my bippy that the GPS was the more accurate of the two.

I flew a VOR approach two weeks ago. Both heads checked before the flight. Both heads tuned/identified. Both OBS set to the same radial. Both put me a half mile right of final. Switched to the GPS and I was right down the chute.
 
rpadula said:
This is so true Spike. The sad thing is, Nate (and many of us here) have the know-how to troubleshoot a failing power supply for some hunk o' crap from the 1980's and we're not allowed to.
Click to expand...

Nothing wrong with taking a look then making a decision, right:idea:
 
rpadula said:
This is so true Spike. The sad thing is, Nate (and many of us here) have the know-how to troubleshoot a failing power supply for some hunk o' crap from the 1980's and we're not allowed to.
Click to expand...

In my experience, most problems like this resolve themselves with a thorough looking-over - open the case, look things over, some magic happens, *poof* ---- it works!

'I have no idea where that blown electrolytic cap came from..." :D
 
SCCutler said:
In my experience, most problems like this resolve themselves with a thorough looking-over - open the case, look things over, some magic happens, *poof* ---- it works!

'I have no idea where that blown electrolytic cap came from..." :D
Click to expand...

LOL. How did the smoke get back in there?
 
flyingron said:
True, but you got to prime with something and DME is better than corn sugar.
Click to expand...

Unless you switch to force carb and then you can skip the dme and dextrose, plus save an hour a session. That decision was a no brainer to me :)

To Nate's question, any way to tell if your VOR is going to be inop once ads-B is fully out? That might make the choice much simpler.
 
masloki said:
To Nate's question, any way to tell if your VOR is going to be inop once ads-B is fully out? That might make the choice much simpler.
Click to expand...

Heh. Define "fully-out" for ADS-B.

The FAA has published a timeline for phases of it, but we'll see if they hit them. Same thing for the phase-out of many VORs, but not all yet.

I've looked over the list of scheduled VOR closures in my area. It's definitely going to limit options in the not-too-awfully distant future.

ADS-B doesn't really have to factor in as much other than to know if the chosen GPS can feed the Mode-S that'll shortly be required.

In the end, everything in the panel eventually gets swapped out, Nav-wise. Comm radio wise, they slowly get replaced when Nav devices that have Comm capability push them out of the way.

Instrument wise, the six-pack works and is awfully cheap to keep operational for now, so glass, while nice, probably isn't cost effective yet. One gyro failure in IMC could ruin your whole day, though... so a nice little box of AHRS toys can make a significant difference in safety, if one believes those don't fail. ;)
 
Nate,

When I rebuilt the panel a couple years back I installed a 430W and kept the KN62 because I had enough space and I had found them to be bullet-proof after 27 combined years of flying with two of them that never failed. I'd be surprised if the unit is the problem. YMMV
 
wabower said:
Nate,

When I rebuilt the panel a couple years back I installed a 430W and kept the KN62 because I had enough space and I had found them to be bullet-proof after 27 combined years of flying with two of them that never failed. I'd be surprised if the unit is the problem. YMMV
Click to expand...

I think I'm convinced I want to keep it too. I would really miss those nice digits there counting down...

It's too bad the world has gone to LCD. Those displays on the Kings when working right are very readable in virtually all conditions, and look good too.
 
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