KLN 94 display failure

arnoha

arnoha

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arnoha
Got an aircraft I'm interested in buying, but there's a display anomaly: there's a big, orange circle shining on the right side. It needs repair or replacement. It's getting leased back to a club/school, so the avionics need to stay stock. No Garmin upgrade for this SP. Looks like replacements run about $2500-3000.

Is the display a repairable part? Can it be repaired for less than the cost of a yellow-tag replacement?
 

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NOTE TO RENTERS: This is not a touch screen!
 
flyersfan31 said:
NOTE TO RENTERS: This is not a touch screen!
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Heh. The aircraft is actually currently personally owned and has never been rented that I can tell. I've seen this kind of failure before, on one of the SP's I rented in Maui.
 
You might also call Bendix King directly first . I have found their prices unbeatable on autopilots and transponders.


I would also recommend calling Lafayette Avionics for screen replacement . (The kind of specialize in it) they are great to deal with and are priced very well..
http://avionics-laf.com/


negative experience with Bennett they don't stand behind their work, they sent me a broken transponder (verified by avionics shop) and they wouldn't budge an inch.
The screen is replaceable but note Bennett
"We do not have the ability to repair or replace this display."
 
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Display is irrepairable ATM (by manufacturer's choice, btw) but it is replaceable. Find a dead KLN for parts and you could get lucky.
 
BigBadLou said:
Display is irrepairable ATM (by manufacturer's choice, btw) but it is replaceable. Find a dead KLN for parts and you could get lucky.
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Yep. Screen was made with parts that are now unobtanium. I think the components used were even pre-RoHS so no chance in hell they'll be redesigning it with newer parts.
 
Got lucky. Found one locally in perfect working order for $2000. Splitting the cost with the seller.

Now all I gotta do is find a ferry pilot to bring the plane back to me from Florida.
 
So, actually, thinking about this: Can I legally replace the KLN 94 myself? It slides right in and out and is one singular allen to secure.

OK, I know simplicity is irrelevant. I know that it's legal to slide the existing unit in and out for things like practicing in the fixed base. Owners do it all the time. But, for sliding in a new (thought identical) unit that's never been in the airplane: need a mechanic? Logbook entry? What's actually legal?
 
arnoha said:
So, actually, thinking about this: Can I legally replace the KLN 94 myself? It slides right in and out and is one singular allen to secure.

OK, I know simplicity is irrelevant. I know that it's legal to slide the existing unit in and out for things like practicing in the fixed base. Owners do it all the time. But, for sliding in a new (thought identical) unit that's never been in the airplane: need a mechanic? Logbook entry? What's actually legal?
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It would seem to me that where you're going to run into trouble is with your log books. I don't think you can update them to reflect the new unit.

So, you're going to need a signoff.
 
Actually had our local director of maintenance look this up. I'm legal! If there's a tray (there is) and it slides right in and out, it meets the regs for one of the 36 things a pilot may do.
 
What kind of plane? (re: ferry)

My Aztec had a KLN94 that I had the shop put in after buying it. I enjoyed flying with it.
 
retailguy said:
It would seem to me that where you're going to run into trouble is with your log books. I don't think you can update them to reflect the new unit.

So, you're going to need a signoff.
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Of course you can, in fact you're required to properly log and sign off any approved owner/pilot maintenance items with your name and pilots certificate number, and replacing tray mount radios is a listed approved owner/pilot maintenance item in Pt.43.
 
arnoha said:
Actually had our local director of maintenance look this up. I'm legal! If there's a tray (there is) and it slides right in and out, it meets the regs for one of the 36 things a pilot may do.
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Except transponders and DME. Everyone seems to forget that.
 
bnt83 said:
Except transponders and DME. Everyone seems to forget that.
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Transponders, DME, and autopilot.

I get autopilot...a screw-up there involves control of the aircraft.

I kinda get transponders, as they are involved in the pitot/static system. (Sort of. It's only electrical, so not really different, but whatever.) Or maybe it's because they transmit? (But Nav/Comm are OK...)

I don't get DME. GPS is OK (which can substitute for DME), but not an actual DME? Transmit thing again?

BTW...I did find a ferry pilot. The plane now resides at it's home at KRHV and a couple days away from being put on the line there. The KLN 94 ended up being unhappy with the configuration on the backplane. I was unable to correct the problem on the east coast before leaving, so it was a VFR-only GPS for that ride. Turned out not to matter, as we only had a single IFR departure and flew no approaches. Fixed now that there was an opportunity to set the configuration, which I, as a pilot, cannot legally do.
 
Hmm, I just had a -94 in one of our Caravans go out just like that, except it covered the left side of the screen. The dot would get larger with increases i altitude and temperature. I'm no techie, but it seems like a pretty weird failure mode...
 
HighFlyingA380 said:
Hmm, I just had a -94 in one of our Caravans go out just like that, except it covered the left side of the screen. The dot would get larger with increases i altitude and temperature. I'm no techie, but it seems like a pretty weird failure mode...
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I believe it's a leak in the display, which accounts for the changes with temp and altitude. And why it's very nicely circular and does not follow pixel boundaries. LCD stands for Liquid Crystal Display, as I'm sure you already know. Liquid really means liquid here! It's probably a delamination of the transparent layers resulting in the leak. But that's just a guess.

The other place I saw it was in Maui. Seems like sun/heat exposure is a risk factor for this failure. Use sun shades!
 
arnoha said:
I believe it's a leak in the display, which accounts for the changes with temp and altitude. And why it's very nicely circular and does not follow pixel boundaries. LCD stands for Liquid Crystal Display, as I'm sure you already know. Liquid really means liquid here! It's probably a delamination of the transparent layers resulting in the leak. But that's just a guess.

The other place I saw it was in Maui. Seems like sun/heat exposure is a risk factor for this failure. Use sun shades!
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Interesting, thanks. IIRC, the plane of ours it happened in came from Mexico, so it seems the heat did indeed do quite a number on it.
 
arnoha said:
Actually had our local director of maintenance look this up. I'm legal! If there's a tray (there is) and it slides right in and out, it meets the regs for one of the 36 things a pilot may do.
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Henning said:
Of course you can, in fact you're required to properly log and sign off any approved owner/pilot maintenance items with your name and pilots certificate number, and replacing tray mount radios is a listed approved owner/pilot maintenance item in Pt.43.
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Don't forget that technically it needs a W&B change that the pilot can't do, however.

We had two W&B written up for the 182 when we were having DME problems so we could pull it and replace it at will. Just use the correct W&B numbers and keep both on board.

Frankly it's only a lb or two and it's not going to make a hill of beans worth of difference in the flight characteristics, but technically if you're gonna fly it with a hole in the panel, get an A&P to write up a legal W&B change for it.
 
What's up with the DME not being able to be replaced? (I'm guessing that pulling it is fine... Certainly can't cause any harm...)

Guess we missed that but it's out of the airplane right now and well-dead anyway. Our mechanic also must have missed it, because the dual W&B was his idea.
 
denverpilot said:
Don't forget that technically it needs a W&B change that the pilot can't do, however.

We had two W&B written up for the 182 when we were having DME problems so we could pull it and replace it at will. Just use the correct W&B numbers and keep both on board.

Frankly it's only a lb or two and it's not going to make a hill of beans worth of difference in the flight characteristics, but technically if you're gonna fly it with a hole in the panel, get an A&P to write up a legal W&B change for it.
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I never flew it with a hole in the panel. I swapped one KLN 94 for another. I'm aware of the W&B issue, though that only applies if the change is a pound or more, I believe. Weighing the KLN...it's 3 lbs. So, that would technically have been a problem.
 
denverpilot said:
Don't forget that technically it needs a W&B change that the pilot can't do, however.

We had two W&B written up for the 182 when we were having DME problems so we could pull it and replace it at will. Just use the correct W&B numbers and keep both on board.

Frankly it's only a lb or two and it's not going to make a hill of beans worth of difference in the flight characteristics, but technically if you're gonna fly it with a hole in the panel, get an A&P to write up a legal W&B change for it.
Click to expand...

If you slide out one KLN-94 and swap in one with a different serial number, why would that require a new W&B?:dunno:
 
Henning said:
If you slide out one KLN-94 and swap in one with a different serial number, why would that require a new W&B?:dunno:
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It was in and out on different "professional avionics tech's" workbenches on and off for months. You know, the ones who claim they know discreet electronics and how to fix them?

My buddy who worked for King in Kansas back in the day is fit to be tied that we haven't given him a crack at it. But of course his repairs wouldn't be legal... Even though they were on the bench in KS thirty years ago.

We pretty much gave up on it some time ago and decided it'll be replaced with a GPS sooner or later anyway. Ironically the last time it worked was on my flight home from my IFR checkride. I guess it gave its last during all of that. Way nicer to fly a /A than a /U on the checkride too.
 
If you replace it what would it b I don't care much about the 650 touch $$$
 
If you replace it what would it be not a650 touch I hope to much $$$$$
 
Replace it with a WAAS capable GPS. You’ll need it for ADSB in a couple of years.
 
Billtiz thanks for your reply but what kind of gps do not care much for 650 garmin
 
I'd like to thank @Tennis for "serving up" this necro thread. I always enjoy necros that feature Henning.

And since you don't like the GTN 650 just get a GTN 750. Or an IFD540. They're nice.
 
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