fppilot

KAP140 Autopilot Tutorial

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With so many of our simulator aircraft we find very similar autopilots. Not all the same, but the operation is usually quite straight forward, and thus fairly simple.  Now comes along a new kid on the block...  I'll be the first to say that about once each flight, and in cases more than once, the KAP140 implementation in this new Redux has left me scratching my head.  I have found myself going off course and on occasion climbing or descending through target altitudes.  After watching the linked video below, it seems this Redux KAP140 may be the best yet in terms of modeling the real thing.  Not saying it is perfect yet.  Somehow today I blew a RNAV approach, not on vertical guidance, but on lateral guidance. Was it really me, with my experience?  (Clue: upon engaging APR mode the AP annunciated both NAV and HDG and perhaps something else I was not watchful for.)  Or is this one more true and I failed to read the manual?  The approach issue has me perplexed, but this video answers some other question I had....  It's a bit slow and dry, but educational.

https://www.youtube.com/watch?v=laz1jcwdLvQ

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Posted (edited)

Frank,

Not sure if you were asking for help with the KAP140 or just expounding on it's realism virtues.  In either case, I found that the videos I found didn't really help me,  It always seemed to be "I don't know how to do it and you do, so I don't understand what you are doing" scenario for me.  I'm kinda dense that way... :blink:

When I purchased the A2A Cessna 172 I discovered quickly that I had no idea how to use/set/engage the KAP140 Autopilot it came with.  The manual didn't really cover it in very much detail.  I finally went to Honeywell and downloaded the real deal pdf manual and instruction documents here...

https://www.bendixking.com/HWL/media/PDF/PilotsGuides/PG-KAP140.pdf

Not sure which model is used in the Redux, but all three styles of the KAP140 are discussed in the linked document.

Since then I have had zero trouble.  I especially like that if the NAV 1 receiver "loses" a VOR signal, which it does a lot in the mountainous regions I have been flying in,  the KAP140  automatically reverts to "HDG".  Now all I have to do is remember to set my heading bug to my OBS bug... :biggrin:

The manual starts discussing Approach Mode on page 20 and covers about 6 or 7 pages of different types of approach captures.

Randy

 

Edited by Ramjett
Added Approach Info
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15 hours ago, fppilot said:

With so many of our simulator aircraft we find very similar autopilots. Not all the same, but the operation is usually quite straight forward, and thus fairly simple.  Now comes along a new kid on the block...  I'll be the first to say that about once each flight, and in cases more than once, the KAP140 implementation in this new Redux has left me scratching my head.  I have found myself going off course and on occasion climbing or descending through target altitudes.  After watching the linked video below, it seems this Redux KAP140 may be the best yet in terms of modeling the real thing.  Not saying it is perfect yet.  Somehow today I blew a RNAV approach, not on vertical guidance, but on lateral guidance. Was it really me, with my experience?  (Clue: upon engaging APR mode the AP annunciated both NAV and HDG and perhaps something else I was not watchful for.)  Or is this one more true and I failed to read the manual?  The approach issue has me perplexed, but this video answers some other question I had....  It's a bit slow and dry, but educational.

https://www.youtube.com/watch?v=laz1jcwdLvQ

Not sure why, but the presenter didn't cover the ARM button next to the BARO button, which I routinely use to change altitude after dialing in the new altitude.  His technique of changing altitudes works, of course, just another method of achieving the same thing.

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38 minutes ago, StewartH said:

Not sure why, but the presenter didn't cover the ARM button next to the BARO button, which I routinely use to change altitude after dialing in the new altitude.  His technique of changing altitudes works, of course, just another method of achieving the same thing.

Watch it again then. He not only mentions the ARM button but demonstrates its use many times... :biggrin:

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17 minutes ago, n4gix said:

Watch it again then. He not only mentions the ARM button but demonstrates its use many times... :biggrin:

Bill, I watched it again.  He mentions "ALT ARM" several times, to be sure, in explaining how to set the altitude, but mentions the use of the ARM button only once, as far as I can tell, and this was only to use the button to verify that the AP was indeed in ALT ARM mode.  He never demonstrated the button's use more than that one time.  Not to pick any nits, but he could have explained the use of that button a little more for those folks who don't know what it's used for.  Overall, I found the video mildly informative, but too repetitive, as if the viewer had never used an AP before in his simulator.

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Well, I did have to cough politely at his presentation after having read on the intro screen "Presented Professionally" (or something like that)... :rolleyes:

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Posted (edited)

Guys,

Please do not trust on that "Becoming familiar with the KAP 140 Autopilot" video as it does not reflect the real unit accurately.

The version that comes with the 310 Redux is the most exact that you can find for FS, so I recommend to follow the original manual for training.

Tom

 

 

 

 

Edited by taguilo

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1 hour ago, taguilo said:

The version that comes with the 310 Redux is the most exact that you can find for FS

I have to take your word for it, Tom, having never used one in RL.  It is certainly the most complete version of this AP that I've seen, compared to that presented in any other sim aircraft.  Hats off to Bill and the rest of the Milviz crew!

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8 hours ago, taguilo said:

The version that comes with the 310 Redux is the most exact that you can find for FS, so I recommend to follow the original manual for training.

I agree. In flight it has left me perplexed at least once during each flight.  And to add to that, I spent hours attempting to profile it for my Saitek Multi-Panel in Spad.Next and it appears what I was seeing as conflict (both HDG and NAV annunciated at the same time) may in fact have been true to life.  It is very situational, and sitting on the tarmac idling when attempting the profiling just may have not been the ideal "situation".... 

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Posted (edited)
On 4/13/2018 at 1:46 PM, taguilo said:

The version that comes with the 310 Redux is the most exact that you can find for FS, so I recommend to follow the original manual for training.

OK. Tom. I could use some help.  I have the 140 mastered on all aspects but vertical guidance during approaches. I spent over two hours today shooting approaches into KBMG / RNAV 17.  No matter what I tried I could not get vertical guidance on an RNAV (LPV) approach, and when I shot ILS approaches instead (KBMG ILS 35) I the GS Arm annunciated, but at the FAF when it extinguished, the plane started down, but not at an AP controlled descent rate.  i.e. it was not following.  I had to take over and compensate for a way too deep rate of descent.

I have exhausted my ability to absorb the manual you linked, having scoured it several times, concentrating on the section Two Axis with Altitude Preselect Operation (starts on Page 83).  RNAV vertical guidance is not called out.  On page 110 there is this:  "2. At the FAF, ALT is depressed to activate vertical speed mode. The desired descent rate is obtained using the DN button." So does this mean that this KAP140 does not follow vertical guidance?  That it must be controlled by setting AP VS descent rate at the FAF?

Just to confirm my sanity I shot approaches to the same runways with the original MV C310 and it's AP and all was as expected.

Help? 

Edited by fppilot

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Posted (edited)

Hi Frank,

19 hours ago, fppilot said:

I have the 140 mastered on all aspects but vertical guidance during approaches. I spent over two hours today shooting approaches into KBMG / RNAV 17.  No matter what I tried I could not get vertical guidance on an RNAV (LPV) approach

KBMGLPV17.jpg

Here you have the 310 on finals, KBMG LPV 17. It works perfect with GTN750, I haven't tested with other navigators.

Quote

when I shot ILS approaches instead (KBMG ILS 35) I the GS Arm annunciated, but at the FAF when it extinguished, the plane started down, but not at an AP controlled descent rate.  i.e. it was not following.  I had to take over and compensate for a way too deep rate of descent.

Did you check that GS is displayed on the AP screen? Also remember that, when flying either on NAV or APP/BC, changing the frequency of the active nav source, or switching from GPS to VOR and vice versa automatically reverts the AP mode to HDG hold, (NAV/APP, etc flashing) so you need to be careful in those cases.

I suggest you first of all check this video:

And then reproduce the flight exactly as it is flown, but with the C310 of course!

I did that, and also worked as expected:

LPVApproach.jpg

Hope this helps

Tom

EDIT: Be sure to have the latest version as some VC autopilot issues from the original release have been fixed.

 

Edited by taguilo

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Posted (edited)

Using the latest update for the Redux.  I am using RXP GNS v2.  With LPV annunciated on the GNS and in GNS GPS mode, and with APR selected on the AP I do not get GS enunciated on the AP. 

When shooting an ILS approach instead of the RNAV (and the GNS set accordingly)  I do get the GS annunciation but when the AP starts the plane down there is no vertical speed control.

I am at the specified altitude and I fly this approach very often in other aircraft so I am highly familiar with it.  I will setup a GTN version of the Redux and see what happens there.

I flew several approaches yesterday , a couple each in the original C310, the Turbine Duke V2, and the Milviz B55 Baron and all of the other approaches were spot on.  My RXP GNS settings are the same as I have for the original C310.   

Edited by fppilot

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OK. Finally success!  Still had same issue with the GTN 750 so did a fresh download and reinstalled, making sure Defender and Malware Bytes were disabled.  Same version of the Redux (180412). Odd.  Two different runways RNAV approaches to KBMG (35 and 24) will annunciate and respond to APR GS going from NAV to APR, while two other approaches (17 and 06) would not annunciate and respond GS unless I first went from NAV to HDG and then to APR.

Looks like I am  now good!  But what a frustrating experience!

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4 hours ago, fppilot said:

while two other approaches (17 and 06) would not annunciate and respond GS unless I first went from NAV to HDG and then to APR.

Confirmed this to be the case again this afternoon flying into KEKY, Bessemer, Alabama.  Now in the tutorial video above, the presenter clearly goes directly from NAV to APR and immediately also gets the GS annunciation.  This is not happening for me in the Redux.  Again, at KEKY this time, on approach to RNAV 24, selecting APR directly from NAV mode did not illuminate the GS annunciation.  Selecting HDG, and then again selecting APR did illuminate the GS annunciation and I was able to fly the approach with full vertical guidance.

Does the KAP 140 require that you select APR from HDG mode in order to arm the GS function?

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Frank,

If you repeat the video flight with the 310 you will also get GS ARM message after APR selected from NAV. It should be the case when you are still not in the LPV approach segment, flying in NAV mode, and you select APR. But if you are already on the APR segment in NAV and switch to APR I guess it is possible that GS will not arm as APR detects it is already on a LOC course (captured) and remains in LOC mode.

I am not saying that it must be the case, always or sometimes, but it is probable. The real KAP140 uses to be a PITA for the pilots.

I've included a link to some fair and not so fair comments about KAP behavior on LPV/RNAV approaches.:

https://www.diamondaviators.net/forum/viewtopic.php?t=5024

Sometimes, switching to AP off seems to be the best option.:huh:

Tom

 

 

 

 

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