HSI Issue - common? KI-525A - Glideslope

[Seth]

So I shouldn't have started that discussion about Aspen vs HSI because though I had never had an issue before, I now have one.

 

When conducting a flight early Monday morning to ensure I kept my instrument currency, with a safety pilot on board, I was vectored for an ILS approach and my glide slop indicator never came alive on the approach.  I disconnected the autopilot, and then hand flew the approach on com 2, and did the same on my second approach.

 

On my third approach back to my home base at GAI, I decided to see if in GPS mode the glide slope would come alive.  It did not.  However, the KFC 200 did intercept and start flying the glide path, and did all the way down to "minimums" when I disconnected and landed.

 

Looking more closely a the glide slop indicator, it seems as if the indicator was working, just showing at the top of the instrument (as if I was way low).  As in just where I could see it at times toward the top of the indicator.  This is the yellow indicator on the sides that shows the glide slope.

 

So:

 

1.  The Garmin 430W is sending the proper information to the HSI to fly the plane

2.  The HSI/Autopilot is indeed receiving and flying the Glide Slope on a GPS approach perfectly

3.  The HSI is not indicating visually that proper glide slop

4.  I did not run a check to see if the ILS was flying properly with the Glide Slope - will have to check that another time

 

The glide slope indicator is either not working or working but indicating only at the top of the device

 

I did have the 430W removed and had the software updated.  I realize now that I had not flown an approach since then.  Does that mean potentially that a connector did not get plugged back in correctly and I'm just noticing this?  Is this a typical indicator of a KI-525A getting ready for overhaul?

 

In the future I will fly the heck out of the box when removed and reinstalled to ensure everything was put back properly.  I have already reached out to and left a message for the avionics shop used as they may know more about this issue than me.

 

Thank you in advance for the collective knowledge of MooneySpace

 

-Seth

[Marauder]

I feel for you Seth. I have been working with the Mooney group talking about a group buy on the BK 770. My #2 NAV/Com must have overheard and has been a little flaky lately.

The problem you are describing can happen both on mechanical or glass if the source is messed up. Do you have a separate mechanical switch to go from GPS to ILS? Or do you just need to use the VLOC function on the GPS?

One thing I do like about the Aspen 2000 is the ability to throw all the Nav signals over to the second unit's HSI a to eliminate things.

[Seth]

No mechanical switch.  It's the VLOC/GPS button.

 

However, it flew the GPS approach just fine.  It didn't visually show me on the HSI itself the glideslope even though the AP that was getting the signal from the HS had the GS indicator on instead of the ALT indicator on and was flying the GS.

 

Just visually on the HSI the "bar/needle" never came down.

 

-Seth

[Oldguy]

Seth,

 

There is an article at

 

http://miscsolutions.wordpress.com/2011/06/05/what-you-probably-didnt-know-about-the-bendix-king-ki-525a-hsi/

 

that sounds somewhat similar to your issue. If I tried to explain what it says, I am sure I would mess it up, but see if this helps.

 

John

[Marauder]

No mechanical switch. It's the VLOC/GPS button.

However, it flew the GPS approach just fine. It didn't visually show me on the HSI itself the glideslope even though the AP that was getting the signal from the HS had the GS indicator on instead of the ALT indicator on and was flying the GS.

Just visually on the HSI the "bar/needle" never came down.

-Seth

It's got to be a poor wire connection. I would think Nav signal from the GPS for vertical guidance is separated from the ILS glideslope.

[Danb]

Chris, what is a BK 770?

[Bolter]

I understand the electrical issue from the article.  I had similar behavior that I believe was purely mechanical.  It was definitely not a problem with source because like Seth, everything else was working.  My GS needle was stopped dropping soon after I got the plane.  I believe due to lack of use by the previous owner for an extended period of time, it was getting stuck.  Maybe some lube dried up, or whatever is in the mechanism.  I don't know if it was passing the self check on start up, as I was new to the 430, and did not know to look for it.  I got into the habit of tuning in a GS every now and then if I was not flying enough precision approaches to keep it exercised.  Strangely, the GS absolutely worked during the pre-buy flight, so there is some mystery element to the whole thing.  

 

The problem has not reoccurred in at least 2 years.  This does not meet the standard of a scientific proof, but it is a datapoint.  

 

-dan

[omega708]

Chris, what is a BK 770?

Bendix King KSN-770....

 

http://www.bendixking.com/Products/Displays/Multi-Function-Displays/KSN-770

[Ragsf15e]

I'd also check the HSI vs the 430W "test screen" (that's not what it's called, but close).  When you first turn on the 430W and it asks if you want to refuel/hit ok, you should be on the screen that says something like 1/4 deflection left, 1/2 deflection low or something like that.  Look at the HSI and see if it's actually indicating as it should.

 

I have a similar problem and my A&P and I used this as a starting point to figure out that the HSI wasn't responding to the 430... we slipped in another 430 he had laying around and it worked perfect... thus my 430 glide slope was the problem.  

 

You can also get to this calibration (maybe) page somewhere in the 430W aux menus.  Good luck!

[Piloto]

Try tapping on the HSI glass with your nail. It works on mine.

 

José

[ArtVandelay]

I had a similar problem, turn out to be a bad or loose connection, they clean electric contacts and reinstalled

[PTK]

Seth, you have what's called "sticky" glide slope pointers.

Contact the BK man, Bob Bramble, Aerolab Aviation Services, (913) 680-4169.

He is the specialist on the KI-525-A and KCS-55A components, and also for the KI-256.

He'll clean it and go over the unit thoroughly. And at a small fraction of what others charge, he'll save you money!

The King HSI is like a classic Swiss horological wonder. Hold great kudos and never goes out of style!

[Seth]

Thank you for all of the suggestions.  The article link is very much the issue OR just a sticky needle. 

 

I'll do the test on start up but if I recall I've never had the glideslope show during the start up test.  I'll also tap the unit to see if it's just hung up.

 

I'll call Bob Bramble as well as Lancaster Avionics (the shop that updated the 430W and took it out/hooked it back up).

 

Either Bob will fix the needles or LNS Avionics will hook it back up correctly as it may just be the hook up for the ILS did not get reattached correctly.

 

-Seth

[Alan Fox]

Seth if you need a loaner , I have one I need test flown ..-07 w/bootstrap so it will work in yours..

[Seth]

All fixed!

 

The guy at Lancaster Avionics figured it was one of two issues, and it turned out to be the first - they replaced a capacitor, cleaned it out, and we're working fine now.  All in a few hundred dollars.  That's now twice LNS has fixed equipment for a few hundred dollars.  That's two repairs combined for 2/3 AMU.  They conducted both repairs in the last year on two different items, each time, while I waited a few hours.  Really nice people who know avionics.  From what I am told, their installs are not inexpensive, but they clean out all the old wires and make sure that the aircraft is truly set up right.  Again, I have not had them install anything, but I'd get a quote from them if the time ever came for anything after two positive repair experiences.

 

Also, big thanks to Alan who offered to loan me an identical indicator should mine have need to been overhauled or took too much time.  Thank you Alan.

 

-Seth

[Greg_D]

I'm having the same issue.  No GS bars in the test position when on the ground.  When flying a coupled ILS approach, the autopilot will capture the GS even though the bars don't show up on the 525.  When flying a coupled LPV approach though, the autopilot does not descend and there is no GS annunciation on the autopilot computer. 

Has anyone had these repaired lately, and if so, where and at what cost?

[LANCECASPER]

http://georgetowninstruments.com

About $500 if I remember correctly about 6 months ago.

[Greg_D]

13 hours ago, LANCECASPER said:

http://georgetowninstruments.com

About $500 if I remember correctly about 6 months ago.

I'm wondering if that $500 might be better spent investing in a Garmin G5 now that they will drive a KFC150....

[LANCECASPER]

59 minutes ago, Greg_D said:

I'm wondering if that $500 might be better spent investing in a Garmin G5 now that they will drive a KFC150....

You still need to keep the weakest link tho - the KI256. Hopefully at some point down the road another G5 with a converter box will be able to provide attitude. But then you are getting close to the same price as an Aspen VFR. 

[Greg_D]

28 minutes ago, LANCECASPER said:

You still need to keep the weakest link tho - the KI256. Hopefully at some point down the road another G5 with a converter box will be able to provide attitude. But then you are getting close to the same price as an Aspen VFR. 

Yeah, but the KI256 was overhauled not too long ago.  Still hoping for BK's drop-in replacement, but that's a long shot.  I'm going to OSH tomorrow and see that they have another presentation on the new unit.  Probably the same one they've done the last 3 years.

[Bob - S50]

Here's my plan if my partners agree:

If the KI525 (HSI) quits first, get the G5, GAD29b, and GMU11 to replace it and still drive the KFC200.  $3000 in parts.

If the KI256 quits, pull the entire KFC200, pull the vacuum pump, buy two G5's and an AMU11 to replace the 256 and 525.  That's about $4500 in parts.  Install either a Trio or TruTrak autopilot (which don't need attitude input).  That's another $5000 to $7000 in parts.  Sell the operable parts of the KFC200 to those who still want to keep theirs.  I'm thinking selling price should be about half of the overhaul cost.  Hopefully, selling those parts will pay most of the install cost.

Since the rumored price for BK to repair a KI256 is in the $6500 - $7500 range, for $2000 to $6500 more (best and worst case) I get a solid state AP, get ride of the vacuum pump, and gain about 20 - 25 lbs in useful load.

If the turn coordinator quits, replace it with a Sandia Quattro.

[Greg_D]

2 hours ago, Bob - S50 said:

Here's my plan if my partners agree:

If the KI525 (HSI) quits first, get the G5, GAD29b, and GMU11 to replace it and still drive the KFC200.  $3000 in parts.

If the KI256 quits, pull the entire KFC200, pull the vacuum pump, buy two G5's and an AMU11 to replace the 256 and 525.  That's about $4500 in parts.  Install either a Trio or TruTrak autopilot (which don't need attitude input).  That's another $5000 to $7000 in parts.  Sell the operable parts of the KFC200 to those who still want to keep theirs.  I'm thinking selling price should be about half of the overhaul cost.  Hopefully, selling those parts will pay most of the install cost.

Since the rumored price for BK to repair a KI256 is in the $6500 - $7500 range, for $2000 to $6500 more (best and worst case) I get a solid state AP, get ride of the vacuum pump, and gain about 20 - 25 lbs in useful load.

If the turn coordinator quits, replace it with a Sandia Quattro.

I don't think it's anywhere near $6500 to repair a Ki256.  I paid about $2K a little over two years ago.  There's an outfit in AR that says they will do it for $1K.  Ideally, I'd like to just get rid of all the BK stuff.  I guess it depends on whether or not their KI256 replacement is a real product that will ship or not.

[Bob - S50]

16 hours ago, Greg_D said:

I don't think it's anywhere near $6500 to repair a Ki256.  I paid about $2K a little over two years ago.  There's an outfit in AR that says they will do it for $1K.  Ideally, I'd like to just get rid of all the BK stuff.  I guess it depends on whether or not their KI256 replacement is a real product that will ship or not.

What I was looking at was something I found over at Beechtalk.  The price sheet showed the high cost of overhaul if you have it done by BK.  Since BK has said that in the near future they will allow almost none of their equipment to be field overhauled, that's what I'm looking at for a future cost.  If this threat never happens and I can still get it overhauled for $2000 or maybe even $3000 we would probably do that.  On the other hand, to buy a used one from Sarasota, the list price is $6189.

[flyboy0681]

2 hours ago, Bob - S50 said:

What I was looking at was something I found over at Beechtalk.  The price sheet showed the high cost of overhaul if you have it done by BK.  Since BK has said that in the near future they will allow almost none of their equipment to be field overhauled, that's what I'm looking at for a future cost.  If this threat never happens and I can still get it overhauled for $2000 or maybe even $3000 we would probably do that.  On the other hand, to buy a used one from Sarasota, the list price is $6189.

What is the current status of BK's proposed policy? 

[Bob - S50]

4 hours ago, flyboy0681 said:

What is the current status of BK's proposed policy? 

Take everything with a grain of salt.  We all know how accurate information is that we find on the internet.  However, lacking more info, I'm assuming this is close to the truth.

I haven't seen anything lately.  Last I saw was originally planned for July 1st but later delayed until August 31st.

Also, BK was supposed to come out with a new price list by May 31st but nothing was posted about it.  The prices given over on Beechtalk were:

"I finally dug up the Spex exchange catalog. I figured we should all see some pricing

KI256 (-00): $7,525 ex (core $17,857)
KI256 (-01): $9,132 ex (core $39,934)
KX165A: $2,750 ex (core $4,121-$4,286 dep on dash num)
KI525A (-07): ex $4,205 (core $9,244)
KG102A (-01): ex $6,120 (core $7,233)
GNS-XLS (-0101): ex $52,852 (core $91,162)
SP-200 (-921 SPZ-200A in a KA F90): ex $24,319 (core $31,926)
SP-200 (-916 SPZ-200A in a KA 200): ex $6,016 (core $14,355)
KT-76C: ex $1,560 (core $2,225)"