KFC 225 GPSS WAAS Issue

[mtaccino]

I was visiting my avionics shop the other day and discussing a WAAS upgrade, the subject came up on GPSS and roll steering,  as background I have a 2000 Ovation 2 with a KFC 225 and 2 430’s.  In discussing the WAAS upgrade I told him that being new to autopilots I was interested in GPSS, he told me with WAAS and the 225 it would fly holding patters and procedure turns and no need for GPSS, then I asked him would it also fly flight plans, meaning fly all changes of heading based on flight plan in 430 without having to turn the navigation bug by hand at turning point.  He then said yes, and I should not have to do that with a 430 and 225 without WASS and roll steering was part of the 225 and 430 combo for heading changes, with WAAS upgrade it would fly holding patterns, procedure turns, etcetera.  He said the wiring must be incorrect.  Can anyone shed light on this?  My goal is to upgrade to WAAS and have the 225 fly all aspects of IFR including heading changes, holding patterns, and approaches.  Has anyone done this, is his 225 comment correct (meaning I don’t need GPSS but wiring adjusted) and what was done to make it work?  Right now with the 430 and 225 I have to make all turns in flight plan on 430 using the navigation bug while in NAV mode. Trying to understand it before I sink money into it and not get surprised?  Is he giving me incorrect information on 225 and GPSS?

[jlunseth]

I have the 200, not the 225, but I think they work pretty much the same except yours probably has altitude preselect.  I am not following part of your post, or maybe there is some difference between the systems that I am not aware of.  You talk about needing to turn the "navigation bug" to cause the course of the plane to change while you are in Nav mode.  Are you talking about turning the heading bug or the course needle?  In my aircraft (with the KFC 200), I can either choose "HDG" mode or "NAV" mode.  In HDG mode, the plane responds to the heading bug.  In NAV mode, the heading bug is used to the heading to intercept the course set with the course needle.  The system then ARMs and flies that heading until the selected course is intercepted, at which point it shows CPLD, and from then flies the course selected by the course needle, ignoring the heading bug.  So do you mean you are using the heading bug to change course while in NAV mode, or the course needle.  If you are using the heading bug, that would mean that the AP is not coupling to the selected course.  Either you are not letting it get there, or there is a flaw that does not allow it to couple.  I do believe, though, that once coupled, if you want the course to change you must move the course needle manually.

[jrjaks]

My plane is in the shop now, having the GX-60 replaced with a GNS-430.  THe autopilot is a KAP-150.  Even with the older GX-60, the autopilot would fly my entire flight plan, (ALT hold only), including GPS approach at destination, when in the NAV mode.  The course selector, (OBS, not Heading Bug), in the HSI was used for setting intercept angle.  The heading bug was only for course intercepts while using the ILS on autopilot in Approach mode, or for just flying a selected heading.  It seems to me that the GX-60 coupled to the autopilot would fly the entire course, including turns enroute, without touching the Course selectors, and definitely without touching the Heading Bug.  I am quite certain it will be the same with the 430.

[N513ZM]

yes. A 225 w/ 430/530W will do what you want - ie; fly complete procedure including hold. I have 2000 Ovation2 29-0202 and mine works just fine. There *is* a wiring change that is needed however - seems the factory left out the wire enabling this when they first started putting in 225's as they were not totally familiar with the unit. Once the wire is added it works fine. Contact Scott Cole at Cincinnati Avionics (Sporty's I69) for details.

[N513ZM]

yes. A 225 w/ 430/530W will do what you want - ie; fly complete procedure including hold. I have 2000 Ovation2 29-0202 and mine works just fine. There *is* a wiring change that is needed however - seems the factory left out the wire enabling this when they first started putting in 225's as they were not totally familiar with the unit. Once the wire is added it works fine. Contact Scott Cole at Cincinnati Avionics (Sporty's I69) for details.

[Skywarrior]

Hello, all -

First soloed thirty years ago in a T-28, now purchasing my first aircraft. I grew up in the world of LORAN, NDBs and VORs. I am not as versed in the world of GPS avionics.

I have a bird in the shop for pre-buy right now, and if all goes well, I want to upgrade the existing GNS530 to the WAAS-capable version of same.

This bird has a KFC150 A/P. I understand I need to buy a GPSS converter to get the A/P to fly commands from the GNS530W. Am I understanding this correctly? Can anyone recommend a good GPSS converter for this combo?

 

Thanx,

Chuck

[N513ZM]

I believe most folks use the DAC-GDC31 http://www.sarasotaavionics.com/product.aspx?id=902

[donshapansky]

I have the KFC 150 and wnet through several panel upgrades after a few days of ownership, it had a 530W and I wanted the autopilot to track the approach phase including holds. The answer was by DAC, the model is a GDC 31 Roll Steering Converter, it involves a button that you can select between HDG where the autopilot will follow the heading bug or GPS where the autopilot follows the 530W steering commands and vertical commands when the autopilot 'approach' function is engaged. If you look at my picture files you will see the button on the left side panel picture, it is in HDG mode on the picture.

The autopilot is in 'hdg' mode all the time, unless you are transitioning to the 'approach' phase of the flight, you always have the autopilot in this mode to allow the roll steering to do it's thing. You will notice the needles are always perfectly in line regardless of the HSI nav needle setting. You may get a message to set the nav needle to a certain heading but it has no bearing on the course the aircraft actually flies. That is calulated by the GPS course you have selected for that leg of the flight.

I'm very happy with the DAC converter.

 

Regards:

Don 

[N513ZM]

and just for grins - the DAC in DAC probably means Digital to Analog Converter - cause that's what it is. Your 150 is an analog AP. A regular comm radio or the GNS430 in VLOC is outputting an analog signal. When you switch it to GPS mode it is outputting a digital signal that your AP does not know how to interpet. The GPSS box converts the digital fly left/right/up/down signals into analog fly left/right/up/down that the AP can understand.

The King KFC225 is an all digital AP with built in GPS roll steering. It is capable of operating in analog mode which is how it works in the the early Ovations with the wrong wiring and non WAAS GPS. The missing wire (once installed) is what allows the AP to switch into full digital mode and "listen" to fly up/down/right/left coming out of the GNS430W directly in digital mode. When you are in VLOC the input to the AP is coming from the KI-256 and whatever HSI/EFIS you have and that is analog. So it seems like everything works until you get your Garmin upgraded to WAAS and then you discover it wont fly a hold like advertised - BTDT and hence the info about the missing wire. This is a simplification of how it really works but it's a simplification that works for my brain and the folks at King have corroborated it's accuracy.

[jlunseth]

I just recently had a 430AW and an Icarus SAM rolling steering unit installed.  I already had a KFC 200 in the plane.  Have only been experimenting with it for a couple of weeks.  As I understand it, you load and activate a GPS approach, and put the AP in Hdg. mode.  Then enable the roll steering.  If flies the entire approach, including anticipating any turns.  Very smooth.  Generally, once on the final approach segment I have the needle dialed to the app. course and switch the AP over to Approach mode, which is more precise, then fly the rest of the approach in that configuration.  It also flies Missed Apps. and missed approach holding pattern entries, including a parallel entry.  I do not have alt. preselect, so need to manage the altitude myself, not very difficult.

I was told the primary advantage of roll steering, over just the GPS and AP, is the ability to anticipate turns.  I do not know whether a 430 can do that by itself, although the 430 does show a curved course anticipating turns, so maybe it can.  I do know that flying a GPS approach with the roll steering set up is very smooth, and very little work for the pilot. 

My 200 also will fly an ILS pretty much on its own once it has intercepted the glidepath and is set to Approach mode.  It has a glideslope mode, locks on and flies accurately down the glide slope so the pilot's main job is just to manage airspeed.