Avidyne Homepage
Forum Home Forum Home > Avidyne General > IFD 5 Series & IFD 4 Series Touch Screen GPS/NAV/COM
  New Posts New Posts RSS Feed - Century IV Autopilot
  FAQ FAQ  Forum Search   Register Register  Login Login

Century IV Autopilot

 Post Reply Post Reply
Author
Message
dkallen View Drop Down
Newbie
Newbie
Avatar

Joined: 06 Jan 2017
Location: Texas
Status: Offline
Points: 5
Post Options Post Options   Thanks (0) Thanks(0)   Quote dkallen Quote  Post ReplyReply Direct Link To This Post Topic: Century IV Autopilot
    Posted: 12 May 2020 at 9:55pm
I have a Century IV Autopilot in my Cessna 310Q that we are finally interfacing with my IFD540.  What 
functionality can I expect with them wired together?  Is there any way to get GPSS functionality?

Thanks in Advance.
DK Allen
C-310Q
Back to Top
gzinga View Drop Down
Newbie
Newbie
Avatar

Joined: 23 Mar 2020
Location: KWVI
Status: Offline
Points: 36
Post Options Post Options   Thanks (0) Thanks(0)   Quote gzinga Quote  Post ReplyReply Direct Link To This Post Posted: 13 May 2020 at 9:24am
I am able to get GPSS with the 440, stec30 and the G5. Not the same setup but the GPSS comes from the G5 sending heading inputs to the STEC30 when is in heading mode. 

The course comes from the 440 sending information to the G5(HSI)


Back to Top
mfb View Drop Down
Senior Member
Senior Member


Joined: 20 Dec 2014
Location: KATW
Status: Offline
Points: 241
Post Options Post Options   Thanks (0) Thanks(0)   Quote mfb Quote  Post ReplyReply Direct Link To This Post Posted: 13 May 2020 at 1:19pm
The IFD installation manual appendix includes diagrams showing how to hook up a Century IV autopilot. So you should have no problem.

I have a Century 2000 autopilot connected to my IFD540. It works fine.

If you want GPSS steering (which you should), you'll need a GPSS switch box. Century advertises one but it was out of stock when when we needed it and Century had no idea when it would be available. So we wound up installing an Aspen, which has a GPSS switch included. It works very well.

The functionality I get is: 1) The autopilot will follow the track selected in the IFD, both in GPS and VLOC modes, 2) the autopilot will follow a localizer selected in IFD in VLOC mode, 3) the autopilot will follow the glide slope selected in IFD in VLOC mode, and 4) the autopilot will follow whatever the IFD wants to do in GPSS mode (except localizers and glide slopes).

GPSS steering is important. The IFD will do smart things like procedure turns and holding patterns, but the autopilot won't follow it unless you have GPSS. It also won't smoothly follow turns at waypoints in your flight plan.

Hope this helps.

Mike


Edited by mfb - 13 May 2020 at 1:24pm
Back to Top
dkallen View Drop Down
Newbie
Newbie
Avatar

Joined: 06 Jan 2017
Location: Texas
Status: Offline
Points: 5
Post Options Post Options   Thanks (0) Thanks(0)   Quote dkallen Quote  Post ReplyReply Direct Link To This Post Posted: 14 May 2020 at 12:02pm
Thanks for the info Mike and gzinga

DK Allen
C-310Q
Back to Top
chflyer View Drop Down
Senior Member
Senior Member
Avatar

Joined: 24 Jan 2013
Location: LSZK
Status: Offline
Points: 787
Post Options Post Options   Thanks (0) Thanks(0)   Quote chflyer Quote  Post ReplyReply Direct Link To This Post Posted: 14 May 2020 at 4:15pm
Originally posted by mfb mfb wrote:

So we wound up installing an Aspen, which has a GPSS switch included. It works very well.

I hope so. That's a very expensive GPSS switch! ;-)
Vince
Back to Top
Bob H View Drop Down
Senior Member
Senior Member
Avatar

Joined: 26 Jan 2018
Location: NH - KMHT
Status: Offline
Points: 231
Post Options Post Options   Thanks (0) Thanks(0)   Quote Bob H Quote  Post ReplyReply Direct Link To This Post Posted: 14 May 2020 at 5:00pm
Originally posted by dkallen dkallen wrote:

I have a Century IV Autopilot in my Cessna 310Q that we are finally interfacing with my IFD540.  What 
functionality can I expect with them wired together?  Is there any way to get GPSS functionality?

Thanks in Advance.
When I installed an IFD540 in my aircraft with a Century III, I installed a GPSS digital to analog converter.  Works great.  Having this functionality installed during the upgrade was a no brainer.  While this isn't the one I installed, I happened to notice this one for sale on Beechtalk (or check out Ebay or avionics supply houses).  See product brochure and link below.

DAC GDC31 roll steering(2 yrs old) worked very well when removed $800.00

http://dacint.com/wp-content/uploads/2015/08/GDC31-Brochure.pdf

For sale on the Beechtalk website here:

https://www.beechtalk.com/forums/viewtopic.php?f=44&t=181968

I installed an Icarus SAM.  Very happy with it.  It's no longer in production, but available on the used market.

Bob
Back to Top
forkauto View Drop Down
Groupie
Groupie
Avatar

Joined: 30 Apr 2018
Location: Maryland
Status: Offline
Points: 49
Post Options Post Options   Thanks (0) Thanks(0)   Quote forkauto Quote  Post ReplyReply Direct Link To This Post Posted: 14 May 2020 at 5:06pm
Originally posted by Bob H Bob H wrote:

Originally posted by dkallen dkallen wrote:

I have a Century IV Autopilot in my Cessna 310Q that we are finally interfacing with my IFD540.  What 
functionality can I expect with them wired together?  Is there any way to get GPSS functionality?

Thanks in Advance.
When I installed an IFD540 in my aircraft with a Century III, I installed a GPSS digital to analog converter.  Works great.  Having this functionality installed during the upgrade was a no brainer.  While this isn't the one I installed, I happened to notice this one for sale on Beechtalk (or check out Ebay or avionics supply houses).  See product brochure and link below.

DAC GDC31 roll steering(2 yrs old) worked very well when removed $800.00

http://dacint.com/wp-content/uploads/2015/08/GDC31-Brochure.pdf

For sale on the Beechtalk website here:

https://www.beechtalk.com/forums/viewtopic.php?f=44&t=181968

I installed an Icarus SAM.  Very happy with it.  It's no longer in production, but available on the used market.


The issue with the DAC units are that they charge you $1000 to redo and certify the STC for another N number/plane. 
Back to Top
Bob H View Drop Down
Senior Member
Senior Member
Avatar

Joined: 26 Jan 2018
Location: NH - KMHT
Status: Offline
Points: 231
Post Options Post Options   Thanks (0) Thanks(0)   Quote Bob H Quote  Post ReplyReply Direct Link To This Post Posted: 14 May 2020 at 5:33pm
Originally posted by forkauto forkauto wrote:

The issue with the DAC units are that they charge you $1000 to redo and certify the STC for another N number/plane. 
I'm not sure what that means.  There's an STC and an AML.  The 310Q is listed on the AML.  What certification is required for specific N number/aircraft and why?
Bob
Back to Top
forkauto View Drop Down
Groupie
Groupie
Avatar

Joined: 30 Apr 2018
Location: Maryland
Status: Offline
Points: 49
Post Options Post Options   Thanks (0) Thanks(0)   Quote forkauto Quote  Post ReplyReply Direct Link To This Post Posted: 15 May 2020 at 11:47am
Originally posted by Bob H Bob H wrote:

Originally posted by forkauto forkauto wrote:

The issue with the DAC units are that they charge you $1000 to redo and certify the STC for another N number/plane. 
I'm not sure what that means.  There's an STC and an AML.  The 310Q is listed on the AML.  What certification is required for specific N number/aircraft and why?

When I bought my DAC unit, it had my N number on the STC paperwork. When I took it out for the G5 and 550 install, I called and asked and DAC said whoever I sold it to would have to send back and reissue the STC for there plane and the cost was either 900 or 1000. Many people on the Piper Forum are having the same issue selling theirs as I did. Here is a post from another person about the same issue

quote:  "It will cost a buyer at least $1000 to buy the STC permission letter from DAC to install in their plane, based on the last quote from DAC last year. They are pretty protective of the value of their used products, obviously to make them less attractive than buying a new one. On the other hand, the experimental crowd doesn't need an STC so you might try putting it on the Van's RV site"
Back to Top
Bob H View Drop Down
Senior Member
Senior Member
Avatar

Joined: 26 Jan 2018
Location: NH - KMHT
Status: Offline
Points: 231
Post Options Post Options   Thanks (0) Thanks(0)   Quote Bob H Quote  Post ReplyReply Direct Link To This Post Posted: 15 May 2020 at 12:00pm
Originally posted by forkauto forkauto wrote:

Originally posted by Bob H Bob H wrote:

Originally posted by forkauto forkauto wrote:

The issue with the DAC units are that they charge you $1000 to redo and certify the STC for another N number/plane. 
I'm not sure what that means.  There's an STC and an AML.  The 310Q is listed on the AML.  What certification is required for specific N number/aircraft and why?

When I bought my DAC unit, it had my N number on the STC paperwork. When I took it out for the G5 and 550 install, I called and asked and DAC said whoever I sold it to would have to send back and reissue the STC for there plane and the cost was either 900 or 1000. Many people on the Piper Forum are having the same issue selling theirs as I did. Here is a post from another person about the same issue

quote:  "It will cost a buyer at least $1000 to buy the STC permission letter from DAC to install in their plane, based on the last quote from DAC last year. They are pretty protective of the value of their used products, obviously to make them less attractive than buying a new one. On the other hand, the experimental crowd doesn't need an STC so you might try putting it on the Van's RV site"
Got it!  Too bad!
Bob
Back to Top
gzinga View Drop Down
Newbie
Newbie
Avatar

Joined: 23 Mar 2020
Location: KWVI
Status: Offline
Points: 36
Post Options Post Options   Thanks (0) Thanks(0)   Quote gzinga Quote  Post ReplyReply Direct Link To This Post Posted: 21 May 2020 at 12:42pm
Originally posted by mfb mfb wrote:

The IFD installation manual appendix includes diagrams showing how to hook up a Century IV autopilot. So you should have no problem.

I have a Century 2000 autopilot connected to my IFD540. It works fine.

If you want GPSS steering (which you should), you'll need a GPSS switch box. Century advertises one but it was out of stock when when we needed it and Century had no idea when it would be available. So we wound up installing an Aspen, which has a GPSS switch included. It works very well.

The functionality I get is: 1) The autopilot will follow the track selected in the IFD, both in GPS and VLOC modes, 2) the autopilot will follow a localizer selected in IFD in VLOC mode, 3) the autopilot will follow the glide slope selected in IFD in VLOC mode, and 4) the autopilot will follow whatever the IFD wants to do in GPSS mode (except localizers and glide slopes).

GPSS steering is important. The IFD will do smart things like procedure turns and holding patterns, but the autopilot won't follow it unless you have GPSS. It also won't smoothly follow turns at waypoints in your flight plan.

Hope this helps.

Mike

Hi Mike,

2 questions:

1) let's say that you are shooting an ILS but you are setting it as GPS, the 440 will switch from GPS to LOC once on the FAF. Will the GPSS follow the localizer or should I switch my STEC30 to high?

2) when you say GPSS will follow the GS, is that because the century is a 3 axis autopilot? I don't believe my STEC30 will, even though it has altitude hold.

thank you

Back to Top
mfb View Drop Down
Senior Member
Senior Member


Joined: 20 Dec 2014
Location: KATW
Status: Offline
Points: 241
Post Options Post Options   Thanks (0) Thanks(0)   Quote mfb Quote  Post ReplyReply Direct Link To This Post Posted: 21 May 2020 at 6:20pm
Originally posted by gzinga gzinga wrote:


1) let's say that you are shooting an ILS but you are setting it as GPS, the 440 will switch from GPS to LOC once on the FAF. Will the GPSS follow the localizer or should I switch my STEC30 to high?

2) when you say GPSS will follow the GS, is that because the century is a 3 axis autopilot? I don't believe my STEC30 will, even though it has altitude hold.

thank you


1.  If the IFD440 has switched to LOC mode but the autopilot is still in GPSS mode, I think that the autopilot will follow the localizer but I don't really know; I've never tried it.  That is not normal practice. GPSS mode is not used for approaches and it may not have the the same tolerances that the autopilot does when it's in approach mode. GPSS just spoofs the heading bug and follows whatever heading commands that the IFD is giving it.

2. The autopilot will NOT follow a glideslope when it's in GPSS mode. As I said in the paragraph above, GPSS spoofs the heading bug by substituting heading commands from the IFD for heading commands from the heading bug. It is only for lateral guidance, not vertical.

If you are shooting a full (not vector) approach, the normal procedure is to keep the autopilot in GPSS mode until you intercept the final approach course. When the IFD flips to it's final approach mode (VLOC, LPV, LNAV, etc.), press the Approach button on the autopilot. That will take it out of GPSS mode and it will follow the lateral and vertical (if any) guidance provided by the IFD. (My Century autopilot is a 2-axis autopilot and it will follow glide slopes. Yours may not.)

If you are being vectored for an approach the procedure is the same, except that you do not use GPSS. You steer the aircraft with the heading bug instead. You switch the autopilot to approach mode when you intercept the final approach course.

Remember that the "legacy" autopilots really don't know anything about GPSS mode. When you're using GPSS, the autopilot itself is in heading mode. GPSS is only an external switch that switches the heading commands between the heading bug (GPSS off) and the IFD (GPSS on). So the autopilot is just flying headings, the only difference is where the headings are coming from. 

You would never fly an approach in heading mode, so you should never fly one in GPSS mode.

I hope that all makes sense. GPSS is really an easy thing, once you figure it out. But it's not easy to explain.

Mike



Edited by mfb - 21 May 2020 at 6:25pm
Back to Top
gzinga View Drop Down
Newbie
Newbie
Avatar

Joined: 23 Mar 2020
Location: KWVI
Status: Offline
Points: 36
Post Options Post Options   Thanks (0) Thanks(0)   Quote gzinga Quote  Post ReplyReply Direct Link To This Post Posted: 21 May 2020 at 8:03pm
Hi Mike,

thank you I will give it a shot next time

gabe
Back to Top
chflyer View Drop Down
Senior Member
Senior Member
Avatar

Joined: 24 Jan 2013
Location: LSZK
Status: Offline
Points: 787
Post Options Post Options   Thanks (0) Thanks(0)   Quote chflyer Quote  Post ReplyReply Direct Link To This Post Posted: 23 May 2020 at 10:15am
Gabe, I have almost the same config as you, but with a IFD540, STEC-30, and Sandel 3500 rather than a G5 HSI. I agree with most of Mike's comments, but the IFD will continue to send GPS overlay roll steering data in addition to VHF data after it has switched from GPS to VLOC mode.

If you leave the GPSS switch in GPSS status and the STEC-30 in HDG mode, then the STEC-30 will continue to follow the IFD overlaid GPS horizontal guidance rather than the VHF guidance. If you want to continue using the STEC-30 for VHF lateral guidance once the IFD switches from GPS to VLOC mode, you need to change the GPSS switch to HDG mode and the STEC-30 from HD to TRK HI. You still need to fly the vertical slope manually.

The STEC-30 does not have an approach mode per-se. That is, it does not do (VHF) intercepts although it will track a VHF signal as described in the STEC-30 POH. As you indicate, it does not provide any vertical guidance. It only provides an altitude hold mode activated via on/off switch.

With just an STEC-30+GPSS, one of the big advantages of RNP approaches over VHF is that the IFD provides full FPL course guidance. It allows you to let the IFD use the STEC-30 to fly full T or DME-arc approaches, including procedure turns, holds, etc, right up to and including the missed approach without touching the STEC, leaving you to manually fly just the vertical profile.

Mike,
Do you have a reference for this statement?
"GPSS mode is not used for approaches and it may not have the the same tolerances that the autopilot does when it's in approach mode."

I agree with the last part of that statement, but not the first. GPSS just converts GPS/IFD roll steering data to DC heading error corrections for the A/P. In an RNP approach, the IFD GPS accuracy (and roll steering data guidance) is in accordance with the phase of flight and the approach being flown. I am not aware that associated GPSS conversion to DC heading error is not appropriate or sufficiently precise in this situation. The STEC GPSS POH even describes doing so, up to disconnecting the a/p at the MAP. This is limited to having the a/p in HDG mode (the STEC-30 does not have an approach mode). You are correct, the GPSS is not used (and is in fact automatically disconnected) if an a/p is in NAV, APR, REV, etc, mode.


Edited by chflyer - 23 May 2020 at 10:27am
Vince
Back to Top
Bob H View Drop Down
Senior Member
Senior Member
Avatar

Joined: 26 Jan 2018
Location: NH - KMHT
Status: Offline
Points: 231
Post Options Post Options   Thanks (0) Thanks(0)   Quote Bob H Quote  Post ReplyReply Direct Link To This Post Posted: 23 May 2020 at 12:05pm
Originally posted by chflyer chflyer wrote:

If you leave the GPSS switch in GPSS status and the STEC-30 in HDG mode, then the STEC-30 will continue to follow the IFD overlaid GPS horizontal guidance rather than the VHF guidance. If you want to continue using the STEC-30 for VHF lateral guidance once the IFD switches from GPS to VLOC mode, you need to change the GPSS switch to HDG mode and the STEC-30 from HD to TRK HI. You still need to fly the vertical slope manually.
I'm not familiar with the STEC-30, but am curious about having to change from GPSS to HDG mode when activating TRK HI mode.  My GPSS is only active when the autopilot is in HDG mode.  If I go to any other autopilot mode, the GPSS switch is out of the loop, so it's position is irrelevant.  In the STEC-30, when GPSS is active, does that prevent TRK HI mode from functioning normally using a VHF signal?
Bob
Back to Top
mfb View Drop Down
Senior Member
Senior Member


Joined: 20 Dec 2014
Location: KATW
Status: Offline
Points: 241
Post Options Post Options   Thanks (0) Thanks(0)   Quote mfb Quote  Post ReplyReply Direct Link To This Post Posted: 23 May 2020 at 3:05pm
Originally posted by chflyer chflyer wrote:

Mike,
Do you have a reference for this statement?
"GPSS mode is not used for approaches and it may not have the the same tolerances that the autopilot does when it's in approach mode."

I agree with the last part of that statement, but not the first. GPSS just converts GPS/IFD roll steering data to DC heading error corrections for the A/P. In an RNP approach, the IFD GPS accuracy (and roll steering data guidance) is in accordance with the phase of flight and the approach being flown. I am not aware that associated GPSS conversion to DC heading error is not appropriate or sufficiently precise in this situation. The STEC GPSS POH even describes doing so, up to disconnecting the a/p at the MAP. This is limited to having the a/p in HDG mode (the STEC-30 does not have an approach mode). You are correct, the GPSS is not used (and is in fact automatically disconnected) if an a/p is in NAV, APR, REV, etc, mode.

I don't have any reference that says that I can't use GPSS for approaches. But I don't have anything specific that says I can, either. 

My Century 2000 autopilot was designed and a long time ago, before anyone ever heard of GPSS. I  know that the autopilot is certified for VOR approaches in the NAV mode and ILS/LOC approaches in the APR mode. As far as the autopilot knows, an LNAV or LPV approach is the same as a VOR or ILS approach, so it uses the same procedures and the same tracking standards for GPS as it did for VHF navigation.

In GPSS mode the IFD is supplying the tracking commands and the autopilot is using whatever heading tolerances it normally uses. I don't know what any of those tolerances are and the autopilot was not certified with them in mind. So I don't do it.

If I had a modern Garmin or Avidyne autopilot things might be different. But I don't. 

Look in the pilot's handbook and/or flight manual supplement for your STEC. The approved flight procedures and the limitations should be there. Does it say anything about GPSS on approaches? If it does, fine. If not you would have a hard time arguing that a GPSS approach is an approved procedure.

Mike




Back to Top
chflyer View Drop Down
Senior Member
Senior Member
Avatar

Joined: 24 Jan 2013
Location: LSZK
Status: Offline
Points: 787
Post Options Post Options   Thanks (0) Thanks(0)   Quote chflyer Quote  Post ReplyReply Direct Link To This Post Posted: 23 May 2020 at 5:26pm
As mentioned, the STEC GPSS POH specifically describes using GPSS mode (and HDG mode on the a/p) to do GPS approaches and GPS overlay of VHF approaches. Pages 3-6 to 3-9 describe doing this for GPS overlay of a VOR/DME app, GPS "T" approach, GPS app with holding pattern, and GPS overlay of a VOR approach with PT. But the a/p MUST be in HDG mode. As soon as another a/p mode is selected, the GPSS decouples from the a/p.

The STEC GPSS is designed for and compatible with STEC autopilots. I'm not aware if it is certified for use with Century a/p. But I don't see how the a/p will be able to distinguish DC heading error corrections received from a heading system (HSI/CDI) for a VHF approach from those received from a GPSS for an RNP LNAV or LPV approach. The tracking accuracy is in the DC input to the a/p. If the a/p can track a LOC using CDI input, then the same DC input from a GPSS for an LPV will result in the same tracking accuracy.
Vince
Back to Top
chflyer View Drop Down
Senior Member
Senior Member
Avatar

Joined: 24 Jan 2013
Location: LSZK
Status: Offline
Points: 787
Post Options Post Options   Thanks (0) Thanks(0)   Quote chflyer Quote  Post ReplyReply Direct Link To This Post Posted: 23 May 2020 at 5:33pm
You are correct Bob. If you change the STEC-30 from HDG mode to TRK HI mode, then the GPSS is decoupled and the a/p will track the HSI/CDI input. I just change the GPSS to HDG as a mental trigger to ensure that I remember to change the STEC-30 setting and be sure that GPSS is decoupled. But that step isn't necessary. As mentioned, GPSS mode is only active when the a/p is in HDG mode.
Vince
Back to Top
 Post Reply Post Reply
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.01
Copyright ©2001-2018 Web Wiz Ltd.

This page was generated in 0.094 seconds.