Failing KCS-55A gyro

[ZamF16]

I recently had my HDG warning flag appear in my HSI (KCS-55A) and the compass card start to drift back and forth about plus/minus 5 degrees. Bendix King tells me it is time to have my gyro (KG-102A) overhauled. Does anyone have an avionics shop they recommend?

[danb35]

Bob Bramble, www.aerolabaviation.com.

[jetdriven]

For the 3k it may cost to overhaul, it might be better to buy a used one off ebay.

[AndyFromCB]

I second that notion, I picked up a complete back up set, head unit, remote gyro, compass sensor and control panel free/slave switch with 8130 for a grand on ebay.

[mooney2201]

i just had a complete garmin upgrade,,my gyro has only 30 hrs on it completely overhauled,to new highest mod,this unit was traded in,shop is now closed,call helocopter transport services,at martin state airport in maryland,they will gladly sell it just to recoup,some investment,its in mint cond.....ask for derrick to give you a price,hope this helps,beware there are units on ebay,i paid 2400.00 from duncan aviation to completely overhaul this unit,i know this works great,dont waste at least one thousand dollars on a unit that may fail,your life rests on that unit,,,,

[Randy_B]

I went thru the very same issue on a KAP-150 system about 6 months ago. The KG-102A was overhauled. However, the KI525A was too old for the upgrades/repairs that were needed. A replacement was sourced for about 3K. The work included an internal battery for a GNS480 and a trim system checkout for around 7K total. American Avionics in Seattle (Boeing Field) performed the work. I was happy with their work and service. They were able to do the work in-house and I was only down for two weeks, mostly waiting for the new HSI. They may not be the least expensive but the service and communication was good.

Randy

84' M20J

[AndyFromCB]

At 7 grand, wouldn't Aspen make a lot more sense for only 5 grand more?

[BorealOne]

I've learned that a compass deviation/hdg flag can also indicate a lower than req'd voltage - often caused by one of the batteries starting to go flat. I've solved this problem a couple of times without an avionics overhaul - test both batteries and if one is going down, replace it and see if that solves the problem

[ZamF16]

I contacted Aerolab Aviation this morning. They have an overhauled gyro sitting on the shelf ready to swap into my KG-102A for $1500. WIll look on ebay for other options, but likely will go with the Aerolab option.

Any idea how long these gyros typically last between overhauls?

[ZamF16]

I've learned that a compass deviation/hdg flag can also indicate a lower than req'd voltage - often caused by one of the batteries starting to go flat. I've solved this problem a couple of times without an avionics overhaul - test both batteries and if one is going down, replace it and see if that solves the problem

BorealOne,

I thought the same thing. However, I also have the compass card drifting back and forth, and it is slow to slave. Then when it does, it overshoots and gradually narrows back in on the correct heading. The avionics shop tells me it is either the gyro or the optics in the gyro. He won't know until he gets it on a bench. He said he will run diagnostics for free. If nothing is wrong, he will send it back for the cost of shipping.

-Zam

[Indianarob]

Take it to Muncie Aviation (MIE) they will bench test it and repair right there. I just had a servo motor and IC put and mine, Yellow tagged for 1200 bucks.

[fantom]

I contacted Aerolab Aviation this morning. They have an overhauled gyro sitting on the shelf ready to swap into my KG-102A for $1500. WIll look on ebay for other options, but likely will go with the Aerolab option.

Any idea how long these gyros typically last between overhauls?

I paid about a grand to O/H my 102A, at a local shop. They should be good for at least ten years; my went for about 15 years. The more you use them, the happier the gyros are.

[johnggreen]

The KI-256 and the KCS-55 are probably the two weakest links in my avionics panel (and anyone else's too). By far the best solution is the ASPEN Pro PFD though I don't think you can get it for any $7,000 as one poster alluded to' probably more like $15,000 installed. Especially true if you have an autopilot that is driven by your AI, the 256, as my 225 is.

I'm planning on doing just that this winter when I feel good about grounding the airplane for a month.

Good 55's and the 256's are a dime a dozen on the used market (because of Aspen and Garmin PFD upgrades) so that is a good argument against spending 15M. I know a couple of guys who have bought the used 256 units and set them on the shelf in anticipation of the next failure which is never too far off.

Jgreen

[LANCECASPER]

The KG-102A remote gyro was precessing badly, so I had Porter Strait up in Tulsa repair it.

They quoted $1500+ for an overhaul, but I elected to do an Inspect and Repair as Necessary. They said it was in great shape and that all it needed was a capacitor and a routine service. The charges were $330 plus shipping both ways. Works perfectly now. Great service - great company!

[1524J]

Just had my KG-102A overhauled. When the avionics tech finished installing, I reached in and pushed down on the unit, front and back. I noticed the Barry controls were not dampening as well at the front of the tray. Might be something to check. I found a new tray w/ mounts on E-Bay for $100.

[1524J]

I paid $1450 to overhaul the KG-102A. The head unit was going to cost $1100 but my issue was with the gyro.

[Marauder]

This is a subject that I am following with interest.  Our HSI keeps getting "poorly".  What it does is flies slightly to the left of the heading bug and unless very close (20 miles or so) to a VOR station reads 5 degrees differently to our VOR 2 which we know is accurate.  So my thought process is:- rip out the AI and HsI (both King things running a kfc 150) and install an Aspen (sorry Garmin you are WAY WAY WAY too expensive,).  OR since the AI works a treat, just put in a refurb HSI (unless King still make the unit in which case it might be worth me buying a new one. )

A refurb costs approx 3-4K  for the HSI, 

Aspen costs 10k plus install. So I can get three HSIs with warranties for the price of one Aspen.

So apart from the fact that Aspen is glass and all modern etc etc, why should I not just get a refurbished HSI and when that starts playing up, get another?  Surely this is the same for everybody or am I missing something?

However when it comes to GPS navigators then yes I will  spend  the required amount for a GTN650 as it is a great piece of kit.  

 

I agree, if you have no plans on long term retention of the plane, it makes no sense to put much investment in other than those needed to sell at some point.

As a long term owner, I eventually came to the point that I needed to make the jump to GPS and at the same time to the Aspen. The Aspen was installed primarily because I had nothing that would display the new GTN data. The side benefit was that with just the PFD I picked up an HSI that I didn't have and that could display all my Nav signals at once, an AI, an airspeed indicator, an altimeter, a VSI, a backup GPS, a moving map and GPSS -- all backed up with a battery backup system.

Whether it is a G500, an Aspen, an Avidyne or Dynon, these glass panels really add so much to managing a flight.

[Godfather]

I personally really like the 55a HSI.  It provides all the information I need and it is very easy to read and use in flight.  Besides the cost to upkeep I can't really fault the unit.  However, if my plane did not have a HSI I would never spend the money to install the older system.  Definitely the new combo units are the way to go in that situation. 

[PTK]

On April 9, 2016 at 4:26 PM, Hyett6420 said:

This is a subject that I am following with interest.  Our HSI keeps getting "poorly".  What it does is flies slightly to the left of the heading bug and unless very close (20 miles or so) to a VOR station reads 5 degrees differently to our VOR 2 which we know is accurate.  So my thought process is:- rip out the AI and HsI (both King things running a kfc 150) and install an Aspen (sorry Garmin you are WAY WAY WAY too expensive,).  OR since the AI works a treat, just put in a refurb HSI (unless King still make the unit in which case it might be worth me buying a new one. )

A refurb costs approx 3-4K  for the HSI, 

Aspen costs 10k plus install. So I can get three HSIs with warranties for the price of one Aspen.

So apart from the fact that Aspen is glass and all modern etc etc, why should I not just get a refurbished HSI and when that starts playing up, get another?  Surely this is the same for everybody or am I missing something?

However when it comes to GPS navigators then yes I will  spend  the required amount for a GTN650 as it is a great piece of kit.  

 

Andrew, have you had a discussion with Bob Bramble yet?

1(913)680-4169

http://www.aerolabaviation.com

He is the one you need to help you diagnose your issue. 

I agree with you. Personally, I would not be in any real hurry to rip out anything. You have solid and very reliable equipment in the KCS-55A compass system worth keeping.

I have the same equipment and have utilized Mr. Bramble's expertise for both, gyro and HSI. So far I've paid 450$ to have the gyro looked at for something it eas doing and 400$ for the HSI. A grand total of 850$. Not bad for almost 10 years! Theoretically should be good for another ten at least.

Here's one data point. About 5 years ago my buddy and hangar neighbor put an Aspen in his Bonanza. About a year and a half ago he had just landed before me as I pulled up. He was disturbed because he had just returned from the avionics shop where he paid 2 grand to have his aspen swapped.  It had failed on him and it was out of warranty. So in less than 5 years he had gone through two units and had paid dearly for the privilege!

In all fairness anything can fail of course. Would this stop me from installing an aspen? If the overall dollars made sense probably not. For what it's worth this is just one incidental data point for cost comparison.

[PTK]

Andrew, you're not going mad. My thinking is that if you sit back and consider everything you can make a logical decision. Look at the dollars in the decision to install glass and don't ignore the equipment it replaces. That's half the equation! And to take out a KCS-55A would leave big shoes to fill in terms of reliability. If you had no HSI then maybe the decision is more palatable. 

IMO, right now the dollars don't always make sense and glass is indeed overpriced. Additionally there's a lot still up in the air and exciting things are happening. The beauty of your setup is that you already have an ultrareliable electric HSI independent from your vaccuum AI. I would focus my attention in removing the vaccuum all together when the time comes, i.e. KI300. Then you'll have an all electric setup and drive your autopilot! Compare what it'll cost you to accomplish that with an aspen or g500 for that matter!  Folks like to talk about the additional "features" glass gives you like gpss and air data. But puting all your eggs in one basket is not good if the basket goes! You have nothing when the G or aspen red x appears out of the blue!

[1524J]

For guys overhauling the KG-102 (gyro) check your tray shocks. Mine were weak at the front of the tray. 

[flyboy0681]

I wrote about it here recently, but Bramble overhauled our HSI and gyro for $2,100. Prior to that the heading bug was off 8 degrees to the left of the actual course (always fun when ATC give you a heading to fly) and the HSI would get flaky at times. It's like brand new now.

[Jerry 5TJ]

On April 10, 2016 at 6:22 PM, PTK said:

.....You have solid and very reliable equipment in the KCS-55A compass system worth keeping....

Do you have any reliability data to back up that assertion?

I'd guess just the opposite--those mechanical gyros have led a number of good pilots astray.  Many to their deaths.

 

[PTK]

13 minutes ago, Jerry 5TJ said:

Do you have any reliability data to back up that assertion?

I'd guess just the opposite--those mechanical gyros have led a number of good pilots astray.  Many to their deaths.

 

Yes I do, mine. Do you have anything besides your "guess?"

[Godfather]

22 minutes ago, Jerry 5TJ said:

Do you have any reliability data to back up that assertion?

I'd guess just the opposite--those mechanical gyros have led a number of good pilots astray.  Many to their deaths.

 

Do you have any data to back up that assertion?  That the 55 HSI was the main reason good pilots crashed?  Before you answer thing about the thousands of hours these things have navigated over the years...hell fedex has probably put 50k hours on them in the 208's (obviously a WAG on my part)