King KFC225 Autopilot Roll Steering Issue

[bbillb]

Hello;

I'm currently working on my instrument rating in my 2000 Mooney Bravo with non-waas Garmin 530

and the KFC225 autopilot.   During RNAV(gps) approaches the autopilot does not track the course that is

loaded into the 530.    When you come to a 90degree turn in the course that is typical in a gps approach the

autopilot does not turn the aircraft so I have to switch over from Nav mode into Hdg mode to manually steer

the aircraft back onto course.   I thought that roll steering was supposed to "round off the corners" during an

approach and completely follow the gps course that is loaded without having to manually adjust anything.

During the initial phase of the approach I have the 530  in Terminal mode and the KFC225 in Nav mode

Was hoping someone else had run into this issue and could advise what they had done to resolve??

 

Thanks

Bob

 

[takair]

Do you have an HSI?  What type?  If analog (KI-525), you need to turn the course needle to the new course.  True roll steering is only available if you have a GPSS type system.  In those systems the AP is engaged in heading mode and then switched between the bug and the GPS with a seperate switch.  I think what you are calling roll steering is the turn anticiapation function.  When it tells you to turn, you will need to get it to within about 10 degrees of the new course before the nav needle can start to pick up the fine course corrections.  So, when the GPS says "turn to XYZ", under normal conditions you shoudl turn the course needle of the HSI to XYZ.  Try this....if you are tracking the GPS in nav mode, turn the course knob about 30 degrees right.  The airplane should start a turn to the right.  Do the same to the left.  If the airplane continues to track the CDI needle and not follow the course needle at all, then you have a problem in the interconnect.   

[carusoam]

 

First question, which roll steering device has been added to the plane?

Most often you find that there is no roll steering between the GPS and auto pilot of this vintage.

There is an option in the GPS called turn anticipation, this helps initiate the turn in a timely fashion.

The pilot still has to turn the knob on the HSI to the new course.

best regards,

-a-

[bbillb]

Thanks for your reply, but here is what the Honeywell Brochure say verbatim

 

GPS Roll Steering

GPS roll steering has been an integral part of Bendix/King’s upper class

of flight control systems. The KFC 225 now brings this functionality into the

General Aviation market. The GPS roll steering algorithms are so advanced

that they anticipate a course change while tracking a multi-leg flight plan

f rom a GPS, and start turns

 

b e fo re c rossing the waypoint keeping the

bank angles shallow, just like a pilot. The system interfaces directly with

GAMA 429 roll steering information provided by equipment like the

KLN 90B or DC roll steering information from equipment like the KLN94

 

Takair;  I do have the KI-525 hsi, and I will try your suggestion on Monday

when I go up again.  It seems though that if roll steering is working you shouldn't

have to change the course pointer.  My system does not have a switch for gpss

like you are referring to, I believe that is necessary for the kfc-150 and kfc-200.

Also, my instructors Piper has an S-tec 55 which has the switch you mention.

 

Carusoam;  in the KFC225 the roll steering is built in according to their brochure

I think what you are referring to is a Digital to Analogue converter(activated by a switch)

for systems like the kfc-150 or kfc-200.  My aircraft does not have this.

You mentioned turn anticipation as an option; how would I know if my 530 has this or not??

 

Thanks for you help

Bob

 

 

[carusoam]

Bob,

Turn anticipation is probably in the settings page.  I have the ancient KLN 90B that you have referenced above.  

Systems that typically use roll steering have a method of changing the course needle automatically.  These make the glass panels look brilliant.

With the KI 525 the pilot is in charge turning the knob.  This would still be better than going to heading mode first.  Using heading mode for making turns is typical of VOR navigation.  Use heading mode while in the cone of confusion.  This does not apply to GPS navigation.

With the KLN 90B a light flashes to indicate the way point is approaching.  A message pops up to tell you what the new course is.  It is better piloting skill to know these before the lights and messages.

The 525 would need a small motor to move the needle over.  90's technology just did not have the complete system.

I'll see if I can find the KFC 225 manual on line.  It sounds like you have all the parts, but the 525 without a motorized needle it seems to be missing something important.  The course line is an I/O device to communicate with the system.

Best regards,

-a-

[carusoam]

https://www.bendixking.com/servlet/com.honeywell.aes.utility.PDFDownLoadServlet?FileName=/TechPubs/repository/006-18035-0000_1.pdf

Enjoy the read.  It gives step by step examples of how to intercept, adjust the course line and approach etc.

You have a very powerful AP.  Unfortunately, the HSI appears to be the weak spot.  

The AP is integrated into the HSI and compass system.  If you only read the brochure,  the AP is capable of landing on the moon.  Unfortunately the installed equipment did not include the lunar landing unit.

In the manual, you can find an electronic version of the HSI that would probably add the capability you were looking for.

Look into an aspen replacement as a way to add the complete roll steering solution.

While you are at it.  Read and understand the GA function.  It is the flight director Go Around button.

Best regards,

-a-

[takair]

Bob

I suspect that the KFC 225 can also be coupled with EFIS equipped aircraft.  EFIS aircraft slew the course needle for you.  I suspect that King is referring to this feature, which is the common method of "roll steering" on jets and other EFIS equipped planes.  Don't have much experience with the 225, but I'm pretty sure it is the vintage where it relied on auto slew of the needle.  I think some Mooneys had optional EFIS as did Bonanzas and larger.

Your 530 has turn anticipation standard.  If you turn the course needle on your 525 when the 530 says "turn now", you will get a perfect intercept.  Some of the digital HSIs will do this for you.  I think Sandel does it and I would bet the modern Garmins and Aspens will.  That said, your current set up whould do it fairly well with just a little pilot input.  You can argue it keeps the pilot more in the loop than automated roll steering and it gets your course needle to the proper place on the HSI for tracking and situational awareness.  In other words, roll steering or not, you should have the HSI course needle set to correct course anyway.

[takair]

I followed up with some reading and the literature would certainly lead you to believe it has true roll steering even without EFIS.  Found a thread that hints at issues with 430/530.  Go to the link, about half way down.  I would suggest calling either Bendix King or Garmin tech support.  Perhaps your local shop. Or maybe one of the Bravo guys will chime in.  It seems I have been away from the GA avionics for too long and don't want to mislead you.  I do think that my suggestion will work in the short term....but you may not be getting the most bang for the buck.

http://www.pilotsofamerica.com/forum/archive/index.php/t-30429.html

[johnggreen]

Bob,

My 2000 Bravo has the 225 with 430's and King HSI.

After flying the system for 7 years, I still haven't figured it out.  I have gone up for hours at a time, letting the AP shoot approaches (and refuse to shoot approaches) and I don't have a clue.  The post by tacair gives me some ideas, but I'm pretty sure that I have done all that too.

Solution, well so far, I just fly the heading bug until I get established on the FAC (or hand fly), then it seems to be able to find it's way home.

Unless it's really low IFR and I feel like I need to spend my time monitoring the approach, I just hand fly.  It makes me feel so macho to have the needles nailed when I finally break out.

One note of info.  When flying in rain, you will find that the laminar wing of the Mooney has to pitch up to produce the needed lift.  Meaning, the pitch attitude when you break out will be a lot higher than you expect.  I was shooting a low ILS approach into Manassas, VA one time in rain.  I was letting George do the job, which he was, and when my wife called out visual at about 300', I couldn't see over the darn nose!!!  Seriously, you will need to raise your seat in rain.

Tomorrow, I think I'll shoot a few approaches and see if tacair is letting us in on something or just messing with us.

Jgreen

[carusoam]

Answer found...

Takair's post reminded me of a conversation posted a while ago...

http://www.mooneyspace.com/index.cfm?mainaction=posts&forumid=3&threadid=568

Garmins and KFC 225 are capable.  Wiring update is required to work properly.

See this thread for contacts and explanation.

Good luck,

-a-

[bbillb]

Takair; I will try your suggestion of turning the course indicator when the 530 says to turn.  From memory though it seems that when in Nav mode with the 225 that I can set the course pointer to anything you want and it just follows the gps signal from the 530.  I will definitely give it a try though....

Carusoam; I have read the KFC 225 Pilots Guide from Honeywell backwards and forwards several times but nowhere does it even mention anything about roll steering.  Oh well, I guess next step is to call Honeywell and see what they have to say.  I did see that thread that you mentioned but I was pretty sure the previous owner had mentioned to me that the "roll steering" was a great feature on this aircraft...., so I assumed that the wiring must be correct and maybe I was just doing something wrong.  I will look into the wiring issue also to make sure.

Thanks guys for all the info

 

Bob

 

 

 

[carusoam]

Bob,

Keep on it.  I think you have something special that works beyond what the manuals indicate.  It was an unusual time in history.  Things advanced in the industry faster than Mooney could keep up.

The back door that allows for the system to follow the GPS without the requirement to adjust the course needle is somewhat similar to following an ILS/LOC.  The course line does not need to be set for an ILS.  It is somehow implied.  Honeywell recommends setting the course line for a human memory aid in this case.

It seems that if the AP thinks it is following an ILS and the GPS plays along giving ILS like signals, the AP should blissfully follow along.

Is the previous owner still available to ask?

Was the POH updated with supplements?  (probably officially missing what you seek)

Best regards,

-a-

 

[bbillb]

The KFC225 Honeywell Pilot Guide that you mentioned is much more informative than the POH

Basically the POH is just a subset of the Pilot Guide and also does not mention anything about roll steering.

I will try and call the previous owner to see what he remembers.  I also pm'ed mtaccino (who started the thread

that you mention) to see if He ever got his issue resolved.  Looks like in his Ovation he had to turn his course pointer

when the Garmin told him to turn, so maybe that is how it is supposed to work.  Hopefully He will see this and chime in.

 

Thanks

Bob

[takair]

I don't have much experience with the 225, but in most older analog type autopilots you should set the course needle during an ILS approach in order to get full steering.  In most autopilots the course needle provides coarse steering (coarse vs course) and the CDI (the nav needle) offers fine steering.  So, when in approach, the course needle still does offer steering to the autopilot.  Unfortunately, when modifying an airplane, many shops do not wire the nav source, HSI, and autopilot correctly.  That is why so many people end up using the heading bug until the course is intercepted.  The nav needle will allow tracking once within 10 degrees or so.  It is unfortunate how many autopilots are underutilized due to poor installations.  Basically the install manuals are not great and many installers are not pilots.  Even an old Brittain or Century is very capable if installed correctly.  Bob is right, the Bendix manual is terrible.  I read through it and one thing jumps out.  The HSI section is essentially cut and paste from a the HSI manual with no thought to the fact that it is inserted in the autopilot manual.  No mention of roll steering except in the sales brochures. 

I mentioned checking the function of the course needle.  If you guys try it, see what it does in nav mode and approach mode.  See what it does when couple to the GPS, the VOR and the ILS.  The most basic Garmin install is such that the steering is the same in GPS, ILS, and VOR. This is indicated by lack of any other switch to tell the HSI/autopilot who is in control.  I will point out that in many older autopilots you will find that the GPS is tracked better in LOC or approach mode.  I suspect this will not work in the 225 unless you are on an LPV approach. 

Quote: carusoam

Bob,

Keep on it.  I think you have something special that works beyond what the manuals indicate.  It was an unusual time in history.  Things advanced in the industry faster than Mooney could keep up.

The back door that allows for the system to follow the GPS without the requirement to adjust the course needle is somewhat similar to following an ILS/LOC.  The course line does not need to be set for an ILS.  It is somehow implied.  Honeywell recommends setting the course line for a human memory aid in this case.

It seems that if the AP thinks it is following an ILS and the GPS plays along giving ILS like signals, the AP should blissfully follow along.

Is the previous owner still available to ask?

Was the POH updated with supplements?  (probably officially missing what you seek)

Best regards,

-a-

 

[takair]

Really good discussion on Beechtalk with recommended steps to make it work.  Seems Bendix did a really poor job of communicating this stuff.  Anyway, it is really easy to sign up to that forum and read over it.  I don't think it would be appropriate for me to cut and paste their material....+ it is quite long.  Hope it helps.

http://www.beechtalk.com/forums/viewtopic.php?f=21&t=42845

[jlunseth]

Ok, I think that last post gave me an idea.  When all this is happening, what mode do you have the AP in.  I have the 200 with a separate roll steering unit.  To cause the AP to fly a procedure, I put it in Hdg mode, and the roll steering unit then uses the Hdg input to provide all turns and turn anticipation.  However, once on the FAC it is necessary to go to Apch mode to couple to the GS.  Once in Apch mode the needle rather than roll steering  flies the plane, and it flies on a radial to a GPS waypoint.  So I am thinking that Nav mode in your aircraft probably does the same as my Hdg mode with my roll steering, that is, it uses Roll steering info to fly a course. 

There has to be a way to switch between using GPS steering and using the heading bug to set a course.  If there weren't, you would not be able to take over from the GPS to fly a vector given by ATC.  I bet on your AP the way to do that is to switch between Nav and Hdg. 

So try using Nav to fly the Apch until on the FAC, then dial the FAC in on the needle and switch to Apch.

You do have your GPS in GPS mode and not VLOC mode?

[bbillb]

Takair;

Thanks for the suggestion to sign up for Beechtalk, as they had many threads on the KFC225.

Here is a quote from John Collins who is quite knowledgeable regarding the kfc225

The KFC225 has built in roll steering (often called GPSS on other systems), but it is a well kept secret as there is no mention of its operation in the KFC225 Pilot Guide. Roll steering is automatic and there is no annunciation of its operation. Roll steering is in effect anytime the GNS530W has GPS as the CDI source, the GNS530W is providing the roll steering information, and Nav mode on the KFC225 is engaged. This enables the autopilot to fly the holds, procedure turns, T style 90 degree turns, flightplan course changes, etc.

I talked to him this morning regarding my problem and he pretty much felt that it was a wiring issue.  If the ouput from the Arinc 429 is not wired properly or the 430 not configured properly then the roll steering does not work.  He did say that if you manually changed the course selector when the 530 said to turn this would work as you had suggested; but that is not roll steering.....it should follow the course change automatically.   Here is the required wiring for it to work;

530 Connector P50001 pin2   to  KFC225 Connector P2pin34

530 Connector P50001 pin14 to  KFC225  Connector P1pin7

530 Connector P50001 pin46  to  KFC225 Connector P1pin46

530 Connector P50001 pin47  to  KFC225 Connector P2pin47

If Connector P50006pin29(ILS energize) is connected to KFC225 Connector P1pin7 then remove

 

Anyway, it looks like I have a little work to do, and I will let you know what I find

 

Thanks for all your help,

 

 

Bob

 

[carusoam]

Bob,

Nicely documented.  It seems from reading the previous threads, that mooney did not complete the wiring to enable the full functionality in their early installations.  Now to identify the missing wire and have it installed.

You are right.  Adjusting the course needle manually is not roll steering.

Best regards,

-a-

[bbillb]

jlunseth;

Thanks for your help.  I noticed the problem on a typical RNAV(gps) approach where there is

two 90deg turns  before you get set up on final approach.  The 530 was in GPS mode and the kfc225

was in nav mode tracking to the IAF just fine.  When it got to the first 90deg turn it just blew right through it.

According to John Collins(see above) it should fly any course changes automatically with no input from the pilot

anytime the 530 is in gps mode and the kfc225 is in nav mode.  Once you get on final, then yes you need to switch

autopilot over to approach mode

 

On the kfc225 heading mode will allow me to manually set the couse with the "heading bug"

This works fine for vectors to final, but a little more work when you're flying the full approach.

Nav mode should allow the autopilot to fly the full approach and then all you have to do is switch

over to approach mode when on final.

 

 

Thanks

Bob

[jlunseth]

There are a couple of other glitches that some of us have run into with the 200's, that you should know about when you get your 225 wired correctly.  It may not affect you because you are digital and we are analog.

When flying a GPS RNAV approach it is necessary to go from whatever your roll steering mode is (mine is HDG), to Apch, in order to get the GS to couple, which has been mentioned.  Most RNAV approaches are designed so that you fly the "T" and then fly inbound on the FAC for some time before reaching the FAF, and I have always left the roll steering in charge of the intial inbound leg, and switched to Apch either at or immediately before the FAF.  But I had trouble with the AP declining to couple.  Apparently, the 200 (and I guess the 150 also), need a "closure rate" to the FAC in order to couple.  So if you are already close to being on the FAC, it will not see a closure rate that triggers coupling.  At least, that is the way it has been explained to me.

I have found that the cure that appears to work every time, is to not wait until you are at the Final Approach Fix to switch to Apch mode, but rather to switch when you are inbound on the FAC a couple of miles before the FAF.  It seems to couple every time, at least I have not had it fail.  It may be too that the course deviation width is "zoomed" at this point, and gets too narrow for the AP to reliably couple.  The GPS course width does change twice, going from "enroute" to "final approach."  When and where it switches is info. you will find in the 430/530 manual.  At any rate, that is the issue and that is the fix, dial the FAC in with the HSI needle and switch to Apch. at least a mile or two before the FAF.  Then watch the annunciator to be sure it goes from ARM to CPLD, don't take it for granted.

It might also work to use roll steering on the perpendicular to the FAC, and arm Apch before you get to the FAC, I don't know. I have not tried that because I prefer to leave the GPS in charge that far out from the runway, the aircraft flies more smoothly, not hunting so much. 

[thinwing]

Jlunseth...that is interesting...On my kfc 225 the command buttons for all the modes "work in que"...meaning on a typical appr as commanded by my 530w...the entire appr is loaded incuding missed appr procedure.Than you have the choice to accept vectors and navigate in hdg mode BUT have also pressed the apr button which causes the apr light to annunciate right below the hdging mode.Controller gives you that final intercept vector ,and you roll in the new heading for the intercept...Now if you are hand flying ok...but if in ap mode ,my 530w will annunciate "ap guidance availble.do you wish to engage"This is coming from the 530w which is commanding the whole show.So you go into "procedures"and activate a/p guidance all the while you are still in either hdging mode for the atc intercept or nav mode for own nav to I A fix.Doesnt matter if you are hand flying and just using the flight director bars or coupled to the ap.Once you have enabled a/p output from the 530 the 225 "gets "the message and either the hdg mode goes out or the nav mode goes out with the apr mode light sitting in que comes on an a nice apr w/glide scope couple occurs.This by the way is my standard method in really low IFR...say 300/3/4...and because of the roll steering...the intercept turns,missed approach entries are seamless...a nice smooth turn ...I love the 225 coupled to th 530 wass...sinc kpc

[N513ZM]

As others have touched upon, this is a wiring issue and also may be an issue related to the KI-525.

I own a 2000 Ovation 2 with the KFC225. As previously mentioned the KFC225 is a full DIGITAL AP with BUILT-IN GPSS. However the first few (not sure of how many but some number) planes fitted with this AP and the GNS430 by the factory were mis-wired. How do I know? The factory told my avionics tech this years ago when I had my 430s upgraded to WAAS and the plane was still unable to fly a holding pattern on the approach.

My plane was equipped with a Sandel EFIS with auto-slew so I would get some measure of turn anticipation that masked the problem at first. However in trying to sort out the holding issue we discovered that an additional wire was required (left out in the install) that would allow the AP to talk digitally to the HSI/EFIS instead of analog. 

Once the wire was added it works perfectly. Couple years later I replaced the Sandel with an Aspen and that introduced an interesting luxury problem - there are now 2 devices with GPSS and 2 modes in which to use it! You can leave GPSS turned off on the Aspen and fly using the GPSS in the AP - I find this more intuitive so this is the mode I use. Or, you cen enable GPSS on the Aspen and in that case you fly with the AP in HDG mode all the time - this works fine but I prefer the other method.

[bbillb]

For Documentation Purposes;

The four wires that were needed to couple(arinc 429) the Garmin 530 to the KFC225 were not installed

FROM THE FACTORY!!!  as others have mentioned.   My aircraft is a 2000 Bravo; Serial # 0307

built in the December 2000 timeframe.  If anybody has a Bravo built before that , then your roll

steering probably does not function correctly either.

 

With the 530 in GPS mode and KFC225 in Nav mode:  as Takair mentioned, the autopilot will

follow a 90deg turn in the course if I turned the course selector when the Garmin said to change course.

Thank you all for your help.  I will get the wiring fixed soon.

 

Bob

[jlunseth]

I am posting to find out if the wiring got fixed, if that solved the problem, and generally to find out how well the 225 works in your Bravo now that you have some experience with it.  I am interested in a Bravo with a 225 because it is digital, not analog, and does have built in GPSS, but there is some material out there on the Internet critical of the servos and in fact the whole unit, so I am up in the air.  Any thoughts?

[bbillb]

Jlunseth..., I actually have not fixed the wiring yet; I am one of the early purchasers of the new Avidyne IFD-540 which will also require some wiring changes when installed. I had planned to make all the wiring changes at the same time when I get my 540. Looks like that could still be a few months away. As far as the 225 goes it is an excellent autopilot in my Mooney. Other people have had problems(ie Peter from UK with multiple failures), but I have not seen any issues at all. My aircraft has 900 hours with no autopilot problems noted in the logs. I have about 300 hours in it with no issues. In Peter's case it seems to be a noise issue in the Socato that must not be present in the Mooney. My aircraft has rg-400 cable(low noise) throughout so maybe that is helping me.

As far as flying goes the autopilot has been solid. In the last year I have made several approaches to minimums (1/2mi 200ft) using the autopilot and it has done a great job. The roll steering issue to me is minor but not caused by the autopilot. Looks to me that Mooney dropped the ball on that one and never wired it properly. My serial # is 0307, and at 0331 Mooney started installing the G1000 so only about 24 aircraft "might have been wired correctly".

Here is another article that I found helpful for flying the 225 by Peter Cassidy; http://www.cassidys.ca/server/flying/Papers/Autopilot_Transition.pdf. This describes how to set up the 225 on takeoff and this is how I fly my 225 with good results. One of the most important items I have figured out over the last year is to make sure the aircraft is trimmed properly before turning the autopilot on. If aircraft isn't trimmed properly initially the autopilot seems to have a hard time holding the attitude or altitude that you are expecting it to.

Another thing that would have helped me is to find a instructor that is familiar with the 225. I have had three instructors over the last few years but nobody has had 225 experience so that makes it difficult to learn because your instructor is learning right along with you.

As you know when you're in the soup things get a little exciting when they don't work as you expect. I guess that is why you should never become too reliant on your autopilot that you forget how to hand fly....

Anyway good luck with your decision and hope this helps.