KFC-150 Autopilot

[Fast n' Furious]

In the process of buying a very nice little airplane with a KFC-150 autopilot, electric KSC-55 slaved HSI and a vacuum driven attitude indicator with flight director. The turn coordinator is electric as you might expect and I'd like to remove it and replace it with an electric standby attitude indicator. I've seen the AC that allows me to do this given some conditions but does anyone know if the T/C gives the KFC 150 any input and can anyone pass along a personal experience of making that change with the equipment I described? Thanks.

 

[bbchien]

In the process of buying a very nice little airplane with a KFC-150 autopilot, electric KSC-55 slaved HSI and a vacuum driven attitude indicator with flight director. The turn coordinator is electric as you might expect and I'd like to remove it and replace it with an electric standby attitude indicator. I've seen the AC that allows me to do this given some conditions but does anyone know if the T/C gives the KFC 150 any input and can anyone pass along a personal experience of making that change with the equipment I described? Thanks.

I have to ask my Malibu driving former student, but IIRC when I pulled the breaker for the TC, the yaw damper went nuts and we took it off line.

 

[Maverick]

In the process of buying a very nice little airplane with a KFC-150 autopilot, electric KSC-55 slaved HSI and a vacuum driven attitude indicator with flight director. The turn coordinator is electric as you might expect and I'd like to remove it and replace it with an electric standby attitude indicator. I've seen the AC that allows me to do this given some conditions but does anyone know if the T/C gives the KFC 150 any input and can anyone pass along a personal experience of making that change with the equipment I described? Thanks.

Well, I'm really not familiar with the KFC-150 but I believe my STEC 60-2 relies on signals from the turn coordinator. I was under the impression that was pretty standard for auto pilots but I could be wrong. I have a radio in for repair so I'll be talking to the avionics guy at my airport on monday and I could ask him for you.

What kind of nice little airplane are you looking at?

Jeannie

 

[Iceman]

Well, I'm really not familiar with the KFC-150 but I believe my STEC 60-2 relies on signals from the turn coordinator. I was under the impression that was pretty standard for auto pilots but I could be wrong.

Jeannie

I'm fairly sure that the 150 is a attitude based autopilot instead of a rate based one. This means that most likely you can remove the T/C without a problem. Not many general aviation singles have a yaw damper so I don't think it will be an issue...for those that do you could probably buy a remote mount T/C or place your current one in the right side of the panel.

 

[Iceman]

can anyone pass along a personal experience of making that change with the equipment I described? Thanks.

As far as the backup AI is concerned we put one in about two months ago and love it. We added it to our system instead of replacing the T/C so I'm not sure how I would like that. However, being able to quickly look at the backup AI and make sure everything is doing well is priceless. It's especially important with attitude base auto pilots because if the main AI goes down your autopilot will also stop working. I think it is a great lifesaving device in my opinion.

As far as the other equipment goes I'm not sure about the 150 autopilot but we fly with the 225 and it is awesome. It makes our plane fly like a 747 on approach and captures altitudes exactly every time. The HSI is also a nice one and there are tons of them out there (IMO I like a standard HSI's to some of the new EHSI because they are giving too much extra info).

 

[Dave Siciliano]

John:

I have a KFC-200 in the A-36; it is attitude based. When the AI began to go out, the KFC, when coupled to the ILS, began to wander badly. So, the TC shouldn't be an issue. However, the KFC is also coupled to your HSI. When I lost the HSI once, the KFC wouldn't even engage. I also have a yaw dampener; so, that would affect my plane.

You certainly should talk to an avionics shop. The KFC auto pilots are great when they work, but get information from several places.

I think the back up AI is a great idea and am looking into it in our P-Baron (which also has a KFC-200).

Dave

 

[Henning]

In the process of buying a very nice little airplane with a KFC-150 autopilot, electric KSC-55 slaved HSI and a vacuum driven attitude indicator with flight director. The turn coordinator is electric as you might expect and I'd like to remove it and replace it with an electric standby attitude indicator. I've seen the AC that allows me to do this given some conditions but does anyone know if the T/C gives the KFC 150 any input and can anyone pass along a personal experience of making that change with the equipment I described? Thanks.

Sounds like a nicely equipped aircraft. IIRC the T/C isn't a coupled instrument on that model and I like a backup AI, however I am lax on the idea of removing or even moving the T/C out of my base scan. Surely a plane with this equipment has a bit of extra panel space to mount a small electric AI.

 

[Fast n' Furious]

Thanks to all who responded. The KFC-150 is attitude based and the replacement of the TC with an electric standby attitude indicator is no problem. If the airplane were to have a yaw dampner then the TC would be a player but not in the current configuration. What's the airplane....rhymes with Looney 252.

 

[bbchien]

Thanks to all who responded. The KFC-150 is attitude based and the replacement of the TC with an electric standby attitude indicator is no problem. If the airplane were to have a yaw dampner then the TC would be a player but not in the current configuration. What's the airplane....rhymes with Looney 252.

Sweeter than sweet.... TSIO360 MB1.

 

[Oldrich]

Hello friends,
I am new on this board, so probably my question should be posted somehow different,
but I applogize if I am wrong.
I have a Piper Arrow, which I have upgraded from vacuum Mitchell directional gyro to
Bendix KCS 55 system. Working great, but I have lost the possibility to use my AP
( Autocontrol single axis). Which AP should I look for - KFC or STEC - I like to end
with 2 axis AP.
Thanks Oldrich

 

[kmead]

We install a lot of the stand-by attitude indicators in place of the TC on the KFC 150 and 225 equipped PA 46. Removal of the TC will not affect the autopilot or yaw dampener operations. The Stec equipped aircraft need the TC along for the ride.

Kevin

 

[poadeleted20]

Hello friends,
I am new on this board, so probably my question should be posted somehow different,
but I applogize if I am wrong.

Don't worry about it -- we found it.

I have a Piper Arrow, which I have upgraded from vacuum Mitchell directional gyro to Bendix KCS 55 system. Working great, but I have lost the possibility to use my AP (Autocontrol single axis). Which AP should I look for - KFC or STEC - I like to end with 2 axis AP.

The Bendix KFC series and the KCS 55 were designed to work with each other, so that would be an easy choice. But that doesn't mean you couldn't hook an STec up to the KCS 55, either.

Part of the answer would depend on just what features you want from the autopilot, both in horizontal mode and especially the vertical mode. For example, in the pitch axis, do you just want altitude hold, or do you want a full set of altitude preselect and vertical tracking capability? If you can define more clearly the capabilities you want, it might be easier to make a recommendation.

 

[TMetzinger]

What Ron said... Depending on the suite of features you want, your choices will vary.

The KFC150 is attitude based, meaning it is driven by your attitude indicator gyro as well as barometric input and input from your DG/HSI. It means it will fail if your AI fails. It also means it does a pretty good job in turbulence becauseit can "see" your airplane attitude just like you could.

The KAP140, and several S-Tec models are rate-based, meaning they get roll info from your TC gyro, and pitch info is derived from barometric data. They don't do AS well in turbulence, but they don't fail when your AI does either. S-Tec also makes attitude-based units, and in general, the more features you want, the more likely you'll end up with an attitude-based unit and the more money you'll spend.

If I were putting in a new autopilot system I'd look hard at S-Tec and Chelton, as they've continued to improve their designs. I've flown quite a bit behind the KFC150 system, and it's a good system, but can require tweaking and getting the King AI overhauled can be a bear. We went through three "back to the shop" trips for our AI/FD unit when it failed the first time before we got a replacement that was stable.

 

[poadeleted20]

Tim brings up a good point -- backup capability. With the rate-based units that work of the TC, you can use the autopilot to fly even if the AI or vacuum pump drop dead, but hand-flying is tougher (partial panel skills, and all that). OTOH, if you replace the TC with a backup attitude indicator (like the Castleberry unit), you still have attitude information for hand-flying without the primary AI, but then you lose the autopilot when you lose the primary AI. Which backup mode seems better for you?