HSI just doesn't make sense. Help!

[PTK]

I don't see why bring up parallel track out of left field!

This is not the issue here for a few reasons:

Parallel track, iirc, is not available in non-WAAS GNS x30.

Parallel track has at a minimum a 1 nm offset. Not likely the case here.

Parallel track is not available on an AP past the IAF. 

Why confuse the issue with parallel track of all things!

 

[Marauder]

I don't see why bring up parallel track out of left field!

This is not the issue here for a few reasons:

Parallel track, iirc, is not available in non-WAAS GNS x30.

Parallel track has at a minimum a 1 nm offset. Not likely the case here.

Parallel track is not available on an AP past the IAF. 

Why confuse the issue with parallel track of all things!

 

Because Peter he is looking for causes for the plane to fly offset from the course. Also to educate people that some of the settings in these boxes cause undesired effects.

Was your sole purpose of posting to offer no suggestion? When you are dealing with a problem, all possible causes need to be explored.

Here is my "left of course problem". I did not know at the time the Aspen would command the AP to fly "wings level" and the autopilot would hold altitude when the reversion switch failed in the opposite direction. If it wasn't for some astute observations from someone who viewed this video, I would still be chasing this problem. It came down to just exercising a reversion switch.

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[PTK]

I'm all for exploring possibilities but I also want to be in the ball park and relevent. What I'm not for is chasing wild geese!

My purpose for posting was to offer reasons why parallel track is not the issue here! Read up on it, learn what it is and you'll see!

What was your purpose for bringing up parallel track when the op specifically states he has a 530 non-WAAS and on an ILS? 

If that's not going to send him on a wild goose chase I don't know what is!! 

[jclemens]

8 hours ago, Joe Larussa said:

So here is the deal. I have been trying to understand whats going on with my HSI for a while now. I have a KIng

Hsi with an Stec 60 autopilot and Garmin 530 non Wass. All this equipment is new to me. So when I intercept the ILS

inbound and set the Hsi to the inbound course with autopilot on it steers me right of course. If I set the course selector

roughly 5 degrees to the left it's almost dead on. Looks like the course selector will steer the plane. On my old plane 

with a normal indicator with localizer and glide slope no matter what you set the OBS at if you flew the needles it would

plant you on centerline. If I hand fly with Hsi same applies only with autopilot does it steer off course. Ideas?

Allow me to take a crack at this one.  So, you appear to have two separate issues going on here.  One is that when your CDI needle is centered, your autopilot is right of the intended course.  This is a simple adjustment to the S-tec that any competent S-tec dealer should be able to make.  The other issue is that when you're tuned to an ILS frequency the CDI needle centers to whatever heading you set the OBS to.  Your HSI does not have "ILS lockout" enabled, could be an issue with the HSI, the 530, or the wiring in between.  So, if your flying an ILS approach to runway 070, you need to set the OBS to 070 (or whatever the approach plate says) in order for your CDI needle to center on course.  If ILS lockout was present, it wouldn't matter what the OBS was set to, the needle would center on the ILS course when a LOC frequency was driving it.  Not all HSI's have this feature, but I am guessing your's should.  

[carusoam]

Begs the question...

Which King HSI it's it?

Summarizing what I have understood so far...

1) system is relatively new to the user.  (Leaving the door open for just about type of solution)

2) most parts of the system have proven to work down to the level of properly intercepting the ILS.

2.1) The STec uses the Nav, heading and approach functions as expected including with the GPSS.

2.2) The G530 (nonWAAS) does it's thing as expected supplying data from the GPS constellation until told to follow the localizer portion of the ILS.

3) the issue has been vetted out to be solely flying an offset during the final approach.  Which is following the localizer part of the ILS system.  Knowing if the HSI has ILS lockout capability would be helpful to know (JC).  Get the HSI model number and then check it's settings.  Not sure how to check the settings on that?

4) When hand flying the approach.  The needles center properly.

5) adjusting the heading bug 5° takes up the 5° /offset error. The plane then tracks the localizer by manually washing out the error.

6) The GPS is able to only generate larger offsets and be prior to being in approach mode.  Good to get that goose out of the way. (Marauder and Dr. Garmin) 

7) A couple of STec set-up issues have been brought forth.  PID control loop settings and other set-up things. (PaulM and JC)

Joe,

A) Can you supply the HSI model number.  As JC points out setting the heading bug on the HSI (maybe) shouldn't effect the ability to track the inbound course on a localizer like it does on a VOR.  Could be a setting for the HSI.

B ) Do you have the STec installation manual.  It looks like you may want to read up on some STec settings and check to see if you can obtain what is set in the box before going to the instrument shop for adjustments. They may be available online if you don't have them.

Thank you everyone for allowing me to play through/fly virtual right seat.  I have tried to gather all of the detail in one spot for the various people that may know the answer or have had the experience but did not collect all the details while skimming through over time.  Hope this helps find a solution.  Let me know if I have missed anything.

Best regards,

-a-

[jclemens]

After further review, and assuming the OP has a KCS55A HSI system that was commonly installed by the factory, it doesn't appear that the KI-525A HSI has ILS lockout.  The pilot's guides specify setting the OBS to the inbound course for ILS approaches.  It also calls out for setting the front course inbound course when performing a back course in order to get proper needle sensing.  So, the behavior of his HSI is normal, just not what he's used to seeing.  Like I said before, the offset can be adjusted so the autopilot tracks on course easily enough, assuming everything is functioning properly otherwise.

[PTK]

20 hours ago, Joe Larussa said:

So here is the deal. I have been trying to understand whats going on with my HSI for a while now. I have a KIng

Hsi with an Stec 60 autopilot and Garmin 530 non Wass. All this equipment is new to me. So when I intercept the ILS

inbound and set the Hsi to the inbound course with autopilot on it steers me right of course. If I set the course selector

roughly 5 degrees to the left it's almost dead on. Looks like the course selector will steer the plane. On my old plane 

with a normal indicator with localizer and glide slope no matter what you set the OBS at if you flew the needles it would

plant you on centerline. If I hand fly with Hsi same applies only with autopilot does it steer off course. Ideas?

Joe, have you tried to see what the TC wants to do without vloc signal? IOW have you tried to see how it behaves by centering the course on the HSI while leaving the vor signal that coupled to the ap off? This will remove and zero out any right-left commands from the vor but will show you what the turn coordinator is trying to do. What turn rate it's commanding when in nav mode.

I bet you if you try this you'll see it turning off course as you describe! If it doesn't then no adjustment is needed and your turn coordinator is working fine. But I bet you it will try to turn off course and needs to be adjusted. There is an adjustment that can be made to make it track vloc signals with a centered nav needle on the HSI. 

[Marauder]

39 minutes ago, PTK said:

21 hours ago, Joe Larussa said:

20 hours ago, Joe Larussa said: So here is the deal. I have been trying to understand whats going on with my HSI for a while now. I have a KIng

Hsi with an Stec 60 autopilot and Garmin 530 non Wass. All this equipment is new to me. So when I intercept the ILS

inbound and set the Hsi to the inbound course with autopilot on it steers me right of course. If I set the course selector

roughly 5 degrees to the left it's almost dead on. Looks like the course selector will steer the plane. On my old plane 

with a normal indicator with localizer and glide slope no matter what you set the OBS at if you flew the needles it would

plant you on centerline. If I hand fly with Hsi same applies only with autopilot does it steer off course. Ideas?

 

Joe, have you tried to see what the TC wants to do without vloc signal? IOW have you tried to see how it behaves by centering the course on the HSI while leaving the vor signal that coupled to the ap off? This will remove and zero out any right-left commands from the vor but will show you what the turn coordinator is trying to do. What turn rate it's commanding when in nav mode.

I bet you if you try this you'll see it turning off course as you describe! If it doesn't then no adjustment is needed and your turn coordinator is working fine. But I bet you it will try to turn off course and needs to be adjusted. There is an adjustment that can be made to make it track vloc signals with a centered nav needle on the HSI. 

 

I guess providing wrong information is better than providing ideas. Joe, if you put the STEC in HDG mode and align it with the final course as he suggests, the autopilot will fly the heading you provided it. Unless it is an absolutely windless day, you will fly off course. There are no final course adjustments in HDG mode. If he is suggesting hand flying the signal with the AP not coupled, that would help determine if the HSI is tracking it correctly.

I read JC's replies and I think he is on to the answer. The only way you can fly the airplane on an STEC autopilot with the heading bug in "NAV" mode is when you press HDG and NAV together and outside of the localizer signal. When you do this, it will fly the heading you select on the HSI and then begin capture the localizer when it sees the signal. But once it captures the localizer, heading input is no longer used.

JC's input makes sense but I will look in my STEC manual to see if they mention this.

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[PTK]

The gentleman from the great State of Delaware, please read more carefully. Nowhere did I suggest or even mention HDG mode. The op has clearly stated he has a King HSI. Not a plain heading indicator, a.k.a. DG. Therefore I suggested he center the course pointer on his HSI on the lubber line. Had he said he has a DG I would have suggested to center his heading.

The purpose of my suggestion is to see if the ap tracks vloc with a centered course needle and hopefully shed some light into what the TC wants to do. It really has nothing to do with HDG mode. 

As I said, based on what he has described, I bet an adjustment needs to be made.

[carusoam]

Marauder, while you have the manual out...

From 90s process control technology....

It would be nice to see an 'auto-tune' feature for the PID loops if they have it.  Or some way to put in known parameters for the aircraft, if available.  Having zeros in the values is clearly not the right way to go.

Best regards,

-a-

[N231BN]

Wow, this thread went into left field pretty quick.

It is most likely an internal issue in the KCS-55. Joe, when you fly in HDG mode does the autopilot keep the HDG bug right under the heading indicator or does it like to leave it 5 degrees to the left?(or right?) In NAV or APR mode the autopilot still needs a heading signal to know what direction to fly. With an HSI the course pointer provides this to the autopilot. The King HSI has a known issue of the card losing alignment so the signal it is transmitting doesn't agree with what is being displayed.

You can check this in the setup pages or on the initialization page when you first turn the GPS on. However, if you calibrate this in the GPS it will fly better when tracking a GPS course but not a VOR, ILS, or in HDG mode.

[carusoam]

231BN,

Are you not familiar with Left Field..? 

1) We are still discussing Joe's original request.  (Unusual by the length and time of this thread)

2) Left Field is often indicated largely by pictures that are not of this aviation world...

3) Joe's issue seems to be narrowed down to tracking the localizer of the ILS using the G530. Everything else has been as expected... Which is similar to tracking a VOR, but different.

Since you brought up an interesting point about some HSIs...

Isn't there a test sequence that some HSIs run on start-up going through all the flags and things?  Does it test the position of the card for proper response?

http://www.bendixking.com/Products/Autopilots-Indicators/Compass-Systems/KCS-55A

selecting the proper system documentation seems to start with the autopilot model.  This one is based on the BK KFC225...  The KCS part is about page 27.

I think we are still awaiting Joe's response to what exact HSI hardware he has installed.  Some of these systems are highly integrated with many boxes.

An important detail that JC brought up was the ability to have a setting for 'ILS lockout' that is equipment model dependent....

i have copied a KCS user manual link, prior to me reading it.  Upon reading it it has a lot of detail on the tests it does but the KCS seems to fail without giving a flag...

Best regards,

-a-

[jclemens]

After thinking about this more, than only possible solution I can think of is to pull everything out and replace it with shiny new Garmin boxes.  At the bare minimum your going to need a GTN750, a 650, and a G500.  Call me with a credit card and I'll get it all ordered for you....

[Marauder]

After thinking about this more, than only possible solution I can think of is to pull everything out and replace it with shiny new Garmin boxes.  At the bare minimum your going to need a GTN750, a 650, and a G500.  Call me with a credit card and I'll get it all ordered for you....

That was Peter Garmin's intent all along for this thread to head there.

Let me know if you can get your hands on a GDL-88 with a Capstone protocol so I can get it to display on my Aspen. I'll fly right over.

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[Joe Larussa]

Okay this is going to sound lame but I think the problem is fixed. We overhauled the Kcs55 and the remote gyro. Two thousand dollars later still the same. I think I mentioned earlier the Hsi was oscillating back and forth three degrees. That's what started this whole adventure. Well started noticing the slaving switch was intermittently not working. Shot some contact cleaner in there and all is back to normal. Really???? Shot the ILS today and it was dead nuts! WTF? One more thought or question. If your HSI is off because your flux detector needs some adjusting , when you set the inbound course won't it be off the amount of the deviation? 

[Marauder]

Okay this is going to sound lame but I think the problem is fixed. We overhauled the Kcs55 and the remote gyro. Two thousand dollars later still the same. I think I mentioned earlier the Hsi was oscillating back and forth three degrees. That's what started this whole adventure. Well started noticing the slaving switch was intermittently not working. Shot some contact cleaner in there and all is back to normal. Really???? Shot the ILS today and it was dead nuts! WTF? One more thought or question. If your HSI is off because your flux detector needs some adjusting , when you set the inbound course won't it be off the amount of the deviation? 

Joe -- this is why I was throwing out all those suggestions. When it comes to these avionics, some weird stuff can happen. Look at my YouTube site to see more examples.

The second video I shared was caused by a switch. I didn't understand at the time that when the Aspen loses communication with the AP, it goes wing level. There was nothing wrong with the STEC, there was nothing wrong with the Nav, it was a stupid switch that closed when it should have stayed opened. The key that I didn't pick up immediately was the loss of the flight director on the HSI. You see it show up in the video for a few seconds. When that went away, it was telling me the AP lost communication with the Aspen. I just didn't see it until I recorded it and played it back a few times.

Your flux switch was probably making intermittent contact and was sending the correct heading to the HSI periodically. This would explain the oscillations. I don't know enough about the BK HSI but I suspect it needs to know the correct heading to provide correction to the AP to stay on course for a localizer.

If it doesn't have the correct heading information, I don't know how it knows how to keep the CDI centered. Take a look at this picture. The course it should be flying is 158°, the actual heading is 163° to compensate for the wind coming out of 195° at 21 knots. The ground track is the turquoise symbol at the head of the CDI.

These avionics can do crazy stuff. Glad you figured it out. In my case I periodically exercise the switch.

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[carusoam]

There is something funky about that switch.  Is it a pull to operate like a landing gear switch?

Somebody may have neglected to use it properly in it's life, recently..?

Do you know if you have the ILS Lockout feature on your HSI?

You may want to review your thread...

MooneySpace is a wonderful problem solver,

-a-

[Pictreed]

11 hours ago, jclemens said:

After thinking about this more, than only possible solution I can think of is to pull everything out and replace it with shiny new Garmin boxes.  At the bare minimum your going to need a GTN750, a 650, and a G500.  Call me with a credit card and I'll get it all ordered for you....

I just got a quote for this and with the new transponder/ADS-B setup it would run $52k (minus the GTN 650...I would keep my 430).

Someone mentioned LPV mode.  I'm still a new IFR pilot so correct me if I'm wrong, but his unit won't do LPV since it's not WAAS, right?

[ArtVandelay]

Someone mentioned LPV mode.  I'm still a new IFR pilot so correct me if I'm wrong, but his unit won't do LPV since it's not WAAS, right?

Correct, I use LPV lower limits about half the time, well worth it IMHO.

[PTK]

On 2/7/2016 at 2:23 AM, Pictreed said:

I just got a quote for this and with the new transponder/ADS-B setup it would run $52k (minus the GTN 650...I would keep my 430).

Someone mentioned LPV mode.  I'm still a new IFR pilot so correct me if I'm wrong, but his unit won't do LPV since it's not WAAS, right?

You are correct. With non-WAAS GPS the only straight in minima you can fly are non-precision LNAV down to their published MDA. Another non-precision is the LP minima but this requires WAAS. LP will be offered if it provides lower minima than an LNAV. 

[N231BN]

19 hours ago, carusoam said:

231BN,

Are you not familiar with Left Field..? 

1) We are still discussing Joe's original request.  (Unusual by the length and time of this thread)

2) Left Field is often indicated largely by pictures that are not of this aviation world...

3) Joe's issue seems to be narrowed down to tracking the localizer of the ILS using the G530. Everything else has been as expected... Which is similar to tracking a VOR, but different.

I guess we are still on track, marauders girls haven't showed up yet.(I wasn't going to bring it up but the problem seem to be solved now.)

13 hours ago, Joe Larussa said:

One more thought or question. If your HSI is off because your flux detector needs some adjusting , when you set the inbound course won't it be off the amount of the deviation? 

You are correct. Some autopilots can handle this, it's the same as having a crosswind. Some autopilots seem to struggle, it may be some internal settings. In an A36 I flew for a customer I had to set the course pointer five degrees left every time to be on course, otherwise it would happily fly one dot to the right every time.