KFC 150 porpoising

[gabez]

Hello, 

I am sure this topic has been discussed several times, my KFC 150 has started porpoising. the AI has been recently overhauled so I would eliminate that. The porpoising is not getting better but it is still very random. Nothing comes out when I push the static line drainage. 

How does the KFC hold Alt or manages pitch, is it wired into the static line? 

Thank you 

Gabe

Edited June 20, 2023 by gabez

[Pinecone]

My KAP-150 does this.  I hit the CWS button and it stops, sometimes for no long.

The other suggestion is to clean and lube the yoke tube.  Although some yoke balls are supposed to be used unlubricated.

 

[gabez]

28 minutes ago, Pinecone said:

My KAP-150 does this.  I hit the CWS button and it stops, sometimes for no long.

The other suggestion is to clean and lube the yoke tube.  Although some yoke balls are supposed to be used unlubricated.

 

thanks I will try that. I tried to pull the alt static air...but it didn't make a difference. 

[LANCECASPER]

6 hours ago, gabez said:

Hello, 

I am sure this topic has been discussed several times, my KFC 150 has started porpoising. the AI has been recently overhauled so I would eliminate that. The porpoising is not getting better but it is still very random. Nothing comes out when I push the static line drainage. 

How does the KFC hold Alt or manages pitch, is it wired into the static line? 

Thank you 

Gabe

Where is it getting it's attitude information from?  A KI-256 Attitude indicator, Aspen (EA100), G500 (GAD) or GI275?

[gabez]

11 minutes ago, LANCECASPER said:

Where is it getting it's attitude information from?  A KI-256 Attitude indicator, Aspen (EA100), G500 (GAD) or GI275?

sorry I meant altitude. When you press the altitude hold, is it reading the static line? 

[LANCECASPER]

19 minutes ago, gabez said:

sorry I meant altitude. When you press the altitude hold, is it reading the static line? 

If the attitude indicator has ever been changed out since 1984 when the autopilot was installed, the attitude indicator and autopilot should be re-aligned. When mine was changed out years ago I had the same symptoms until it was re-aligned.

[gabez]

2 minutes ago, LANCECASPER said:

If the attitude indicator has ever been changed out since 1984 when the autopilot was installed, the attitude indicator and autopilot should be re-aligned. When mine was changed out years ago I had the same symptoms until it was re-aligned.

Interesting, the AI KI256 is the original with the plane but it was overhauled about 2 months ago and then is when the problem started so I can see that. Let me check with my avionics guy to see if it is something he can do. 

Gabe

[LANCECASPER]

2 hours ago, gabez said:

Interesting, the AI KI256 is the original with the plane but it was overhauled about 2 months ago and then is when the problem started so I can see that. Let me check with my avionics guy to see if it is something he can do. 

Gabe

Bingo! It think it needs to be aligned with the kc192 computer. Whether this takes a KTS-150 break out box, which very few shops have anymore, I'm not sure.

[PT20J]

I believe it can be aligned on the bench using a fixture that holds the gyro if they have the gyro and the computer. At least that is what Steve at Executive Autopilots told me a few years ago. @Jake@BevanAviation should know.

[gabez]

oof I feel I am f.ed and I see an Aspen in my future. 

[Jake@BevanAviation]

Any time the attitude gyro is repaired or replaced, the system needs to be aligned to the attitude source.  This requires the KTS150 test set, you can make an adapter to run the KI256 with the flight computer to be aligned on the bench.  The KTS150 comes with harness to align it in the aircraft with the attitude gyro on a tilt stand.  

[gabez]

Just now, Jake@BevanAviation said:

Any time the attitude gyro is repaired or replaced, the system needs to be aligned to the attitude source.  This requires the KTS150 test set, you can make an adapter to run the KI256 with the flight computer to be aligned on the bench.  The KTS150 comes with harness to align it in the aircraft with the attitude gyro on a tilt stand.  

thank you sir. does anybody here happen to know a shop in the Bay Area/california that can do it?

 

[kortopates]

Sacramento Executive - Executive Autopilots. they’re the experts on the west coast and not far from you.


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[Pinecone]

6 hours ago, gabez said:

oof I feel I am f.ed and I see an Aspen in my future. 

My airplane, which sometimes porpoises has an Aspen. 

So that may not be a fix.   

[LANCECASPER]

9 hours ago, gabez said:

oof I feel I am f.ed and I see an Aspen in my future. 

If you change to an Aspen that will still have to be aligned to the autopilot with the test box. On many Aspen installations this isn’t done and the result is porpoising.

On a previous airplane I had Aspens, once I had the alignment done the only time my airplane porpoised is when I flew over SeaWorld in San Antonio 

[gabez]

is there a way to avoid or limit the porpoising? or is it just totally random?

[LANCECASPER]

is there a way to avoid or limit the porpoising? or is it just totally random?

The autopilot is doing right now exactly what the attitude indicator is telling it to do. Getting it aligned is the way to avoid or limit porpoising.


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[gabez]

14 minutes ago, LANCECASPER said:

The autopilot is doing right now exactly what the attitude indicator is telling it to do. Getting it aligned is the way to avoid or limit porpoising.


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thank you sir. I emailed a shop in Sacramento to see if they can do it. 

[IvanP]

On 6/21/2023 at 12:01 PM, gabez said:

thank you sir. I emailed a shop in Sacramento to see if they can do it. 

Reviving an old discussion. Did you get the A/P fixed? I have KFC 150 with KI 256 vacuum AI in my plane and the gyro is likely in need of an overhaul and from what I gathered from this discussion, it would also need to be realigned with the AP computer after the overhaul is done. Unfortunately, I am not in a position to go full glass at this time, so overhaul of the Ki 256 is most likely what will happen. I would be interested in your experience with Executive Autopilots as they are pretty close to my location. Thanks in advance for anything you may be willing to share. 

[gabez]

5 hours ago, IvanP said:

Reviving an old discussion. Did you get the A/P fixed? I have KFC 150 with KI 256 vacuum AI in my plane and the gyro is likely in need of an overhaul and from what I gathered from this discussion, it would also need to be realigned with the AP computer after the overhaul is done. Unfortunately, I am not in a position to go full glass at this time, so overhaul of the Ki 256 is most likely what will happen. I would be interested in your experience with Executive Autopilots as they are pretty close to my location. Thanks in advance for anything you may be willing to share. 

hey I actually did not. I cleaned the yoke columns and the problem went away. In regard to Executive, unfortunately I had to cancel twice because of IFR weather, while IFR rated and proficient I wasn't going to get myself in it with a questionable autopilot behavior. On my 3rd reschedule they stopped responding. I don't fault them but that was my experience. I am sure they are fine. 

[Falcon Man]

Executive autopilots appears to be out of business. Andrey does not return equipment he was supposed to repair, texts, nor does the shop answer the phone. I had a KFC 150 porposing issue which they could never resolve.

[kortopates]

1 hour ago, Falcon Man said:

Executive autopilots appears to be out of business. Andrey does not return equipment he was supposed to repair, texts, nor does the shop answer the phone. I had a KFC 150 porposing issue which they could never resolve.

Is this very recent potential closing? They have a 5 star review as recent as 4 months ago.

That said, I would hate to spend much money on a KFC 150 issues since they get very expensive so I solved my porposing issue with a GFC-500 install and couldn't be happier. Its 10x better except for the limitation it won't fly an ILS without GPS! You have to use heading and VS without GPS.

[PT20J]

4 hours ago, kortopates said:

it won't fly an ILS without GPS!

This is true. However, if the external GPS navigator goes down in a G3X installation, the GFC 500 will use the G3X internal GPS for aiding. For a G5 ADI, it is possible to install both the glare shield antenna for the internal GPS receiver and a RS-232 connection to the primary GPS navigator so that the G5 and GFC 500 will still have GPS aiding if the primary navigator goes down. Of course, this won't help you if the GPS system is down due to failures or jamming.

[kortopates]

14 minutes ago, PT20J said:

This is true. However, if the external GPS navigator goes down in a G3X installation, the GFC 500 will use the G3X internal GPS for aiding. For a G5 ADI, it is possible to install both the glare shield antenna for the internal GPS receiver and a RS-232 connection to the primary GPS navigator so that the G5 and GFC 500 will still have GPS aiding if the primary navigator goes down. Of course, this won't help you if the GPS system is down due to failures or jamming.

In the US I've only lost GPS for brief few moments on multiple occasions in different trainers - never my aircraft. Took a long time to figure out but it stemmed from a interference from the radio on the SEE tower frequency where apparently a harmonic from a separate radio on the 120.7 ctaf freq was killing the GPS signal and the unit would have to re-acquire them - all taking time and this happening crossing the FAF added additional challenges. (using the GPS radio was never a problem and the solution for those installations with this issue).

But flying out of the US I have been jammed several times since those jammers are very cheap and easy to get a hold of. Those losses last for many minutes depending on altitude till you get far enough away. Not a big deal when VMC but a real pain in IMC.

In all of these occasions it wouldn't matter how many GPS's you had, but in the latter jamming scenario I tried a portable as well without success.

[IvanP]

10 hours ago, Falcon Man said:

Executive autopilots appears to be out of business. Andrey does not return equipment he was supposed to repair, texts, nor does the shop answer the phone. I had a KFC 150 porposing issue which they could never resolve.

Bummer