Jump to content

KFC200 alerts


Recommended Posts

The POH supplement that comes with the KFC200 installation discuss the alerts incorporated into the system. They include a red TRIM capsule, and an white AP capsule both on the KA285 annunciator panel. Additionally there is a SONALERT tone generator above the right hand passenger seat. The supplement address each of these along with the conditions required for them to active. In the way of a lose summary, the TRIM capsule will light along with the tone when the KC290 mode controller TEST button is held in or a trim failure has occurred. The only other time the tone will active is if power is removed or lost to the KFC295 computer which cause power to be removed from the trim capsule. The AP capsule will will flash 4 times and go out if the autopilot disconnects, commanded or uncommanded.

I have owned this airplane for more than 20 years but just recently started scrutinizing this supplement after I found my SONALERT is not working. Over the years I have had numerous uncommanded AP disconnects. And unless the KA285 annunciator is part of ones scan, the disconnect will easily go unnoticed. Mostly I am alerted to the disconnect because some other parameter that is in my scan is not where it should be, like heading or altitude.

My view is that the logic incorporated in the system is a bit fuzzy. I would like to see a more positive indication of an uncommanded  autopilot disconnect. Like a tone. But that is just my opinion.

Link to comment
Share on other sites

I preflight my KFC-150 AP before every flight per the AFMS and I hear the tone with every pre-flight test. That includes the multiple beeps (4-5) in tandem with the flashing light on the computer and then the tone flashes when disconnecting with the disconnect yoke button. It has always beeped when it disconnects uncommanded with the trim light flashing as well.

  • Like 1
Link to comment
Share on other sites

KAP150 a series of beeps when first activating the AP... every flight.

Powered trim must be on for this to occur.

The series of beeps is the indication that the start-up test has been completed successfully...

A solid tone occurs when disconnecting... either by intention or accidental...

 

In the ’94 O.  Lots of tones replaced a couple of sonalerts.  Even the stall warning is a pleasant tone... :)

Picture an un-nerving pleasant tone....

 

Either way... you want to know when the AP has taken a decision to not help you out any longer...

APs... are incredibly well designed, expected to last, and expected to fail miserably at the same time...  so they get that extra layer of self testing, monitoring, and alerting...

Time to figure out what part is not working...

I had a stall switch stop working once too.  Put that back on the check list.

PP thoughts only, not an instrument tech...

Best regards,

-a-

Link to comment
Share on other sites

According to the KFC 200 Pilot's Guide p 28, "Upon Autopilot disconnect, a Aural Alerter will sound a Sonalert for 2 to 2 1/2 seconds while the AP light on the Annunciator Panel flashes."

You have two issues:

1. As you stated, your sonalert doesn't work.

2. If the autopilot experiences uncommanded disconnects, there is something wrong with it.

I flew a '78 J for 700 hours (probably 500 on the autopilot) with a KFC 200 and never had an uncommanded disconnect.

Skip

 

Edited by PT20J
  • Like 1
Link to comment
Share on other sites

Thanks for that information. I did not have access to the Pilot's Guide but have now downloaded it. I see see the section you address.

My KFC200 supplement however, does not address the feature that the sonalert sounds upon autopilot disconnect.  On the other hand, the Guide does not address the feature that the sonalert sounds during preflight test.(p.27) but the supplement does (p.9). Whom to believe?

Edited by rotorman
Link to comment
Share on other sites

The sonalert, SC 328 I would guess, could have failed, $35 bucks should clear that up. I would be more concerned with the disconnects, and how they occurred. And how the aircraft reacts when the disconnects happen. Depending on the KC 290 controller, you may not have a sonalert. a -00 has no alert, a -01 does. I can help here if you need.

 

Bob Weber

WebairConsulting.com

616 822 1999

  • Like 1
Link to comment
Share on other sites

On 5/18/2019 at 9:39 PM, kortopates said:

I preflight my KFC-150 AP before every flight per the AFMS and I hear the tone with every pre-flight test. That includes the multiple beeps (4-5) in tandem with the flashing light on the computer and then the tone flashes when disconnecting with the disconnect yoke button. It has always beeped when it disconnects uncommanded with the trim light flashing as well.

Whenever I press the Test button I go through the following prayer: "Blessed mother of five beeps, don't fail me now".

Four beeps equals 2 AMU's, six or more, don't bother to ask.

 

Link to comment
Share on other sites

On 5/21/2019 at 5:47 PM, Bob Weber said:

The sonalert, SC 328 I would guess, could have failed, $35 bucks should clear that up. I would be more concerned with the disconnects, and how they occurred. And how the aircraft reacts when the disconnects happen. Depending on the KC 290 controller, you may not have a sonalert. a -00 has no alert, a -01 does. I can help here if you need.

 

Bob Weber

WebairConsulting.com

616 822 1999

Thanks for that very valuable info. Today, on preflight checks I did hear the sonalert. But when I did the checks again at the end of a 1.5 flight, no alerts. So at least I have some clues. 

With respect to the disconnects, they usually happen in when turbulence is present. Today  The disconnects are benign in that it just disconnects and leaves the airplane in the whatever the attitude is at the time. I usually pick it up because the AP light flashes or if I miss that I pick it up from some other an attitude or heading not being where it suppose to be.  

I can't come up with a SC328 sonalert. Could it be SC628. That looks like mine. I can't read my alert part number. Sticker is too old.

Edited by rotorman
Link to comment
Share on other sites

Sonalerts are pretty simple devices and rarely fail -- especially intermittently. Before replacing it, I would test it by disconnecting it from the autopilot and applying power to it. It may be that the driver in the KC 295 is faulty, or there might be a bad connection. If the autopilot disconnects in turbulence, I would suspect it might be related to the KI 256. The KC 295 doesn't know whether it's turbulent or not; the computer is just responding to inputs it receives.

Skip

Link to comment
Share on other sites

6 minutes ago, PT20J said:

Sonalerts are pretty simple devices and rarely fail -- especially intermittently. Before replacing it, I would test it by disconnecting it from the autopilot and applying power to it. It may be that the driver in the KC 295 is faulty, or there might be a bad connection. If the autopilot disconnects in turbulence, I would suspect it might be related to the KI 256. The KC 295 doesn't know whether it's turbulent or not; the computer is just responding to inputs it receives.

Skip

Following from this, look into the wiring to the KI256. If it bumps around and opens a bad connection, that will drop the KFC right away.

Link to comment
Share on other sites

My 82J has three Sonalerts:  Stall warning, gear warning and AP disconnect.    Two of them failed - one was the gear warning that pulses, the other was the AP disconnect which is a solid tone that is pulsed by the KAP 150.

Recently the stall warning has been intermittent and I suspect the Sonalert.

Link to comment
Share on other sites

After verifying which Sonalert is used by the autopilot by eliminating the stall warning, I removed it. I put 12v to it and it didn't even peep. So to make sure, I will swap in the stall warning in its place and see if that fixes the problem.

Link to comment
Share on other sites

On 5/23/2019 at 8:13 PM, rotorman said:

Thanks for that very valuable info. Today, on preflight checks I did hear the sonalert. But when I did the checks again at the end of a 1.5 flight, no alerts. So at least I have some clues. 

With respect to the disconnects, they usually happen in when turbulence is present. Today  The disconnects are benign in that it just disconnects and leaves the airplane in the whatever the attitude is at the time. I usually pick it up because the AP light flashes or if I miss that I pick it up from some other an attitude or heading not being where it suppose to be.  

I can't come up with a SC328 sonalert. Could it be SC628. That looks like mine. I can't read my alert part number. Sticker is too old.

Yes, I stand corrected, SC 628. I would not pursue the KI 256, I would be more interested in the manual electric trim switch and wiring. A voltmeter would do wonders to troubleshoot the sonalert once it fails.

Link to comment
Share on other sites

I swapped in the working stall warning Sonalert in place of the defective autopilot alert and it works as advertised. Unfortunate these Sonalerts are not loud enough to hear with headsets on. I tried researching to see if I could find a louder one but have not had much success. These alerts were fine in the day when the airplane was built and pilots still used mics. But with today's headsets they are inadequate.

Link to comment
Share on other sites

1 hour ago, carusoam said:

 J has Interesting...

The ‘94 Long Body uses electronic sounds... beeeeeeeeep (stall horn)   beep beep beep... (KAP150)

Something to consider if wanting to copy parts out of the official M20 catalog...

Best regards,

-a-

My '94 J has electronic tones that sound through a second overhead speaker as well as the audio panel for stall (steady tone) and landing gear (on-off-on-off tone). But the KAP 150 has a sonalert in the overhead.

Skip

  • Like 1
Link to comment
Share on other sites

19 hours ago, PT20J said:

My KAP 150 sonalert is mounted overhead and I can easily hear it with either my Lightspeed Zulu or Bose A20 headset. Maybe the stall warning sonalert is weak. The SC628 is rated at 68 dBA. 

It is possible that the alert is weak. But it doesn't help that after 50 years around aircraft, starting before there was an awareness that one should use sound protection, there is a good possibility that some of my hearing in the higher frequency ranges is not what it use to be. I also see you are operating a 1994 model which is probably 28V.  As you say the SC628 is rated at 68dBA@6v and 80@28v. I figure about 74@12v. It draws 3mA @6v and 18mA@28v. I am considering another unit that is nearly identical but sounds at 95 to 105dBA. However, it draws 10 to 50mA at 6 to 28v. That seems OK but I am not sure.

Edited by rotorman
Link to comment
Share on other sites

  • 2 weeks later...

I have an ‘80J with  KFC200 autopilot. I get uncommanded disconnects with no sound alert. There seems to be no reason for the disconnect. I either notice the light is no longer on or the airplane is starting to turn. My avionics guy said there is a very weak magnet holding that switch in place and that could be failing. Any comments?

Link to comment
Share on other sites

I have a KFC 200 in my '78 J, which has 3 sonalerts.  The autopilot doesn't make any beeps on disconnect or when pressing test, but I do get the beeps from the electric pitch trim on/off switch, and I was able to confirm that comes from the sonalert that protrudes slightly from the headliner (part no SC628 I believe; the stall and gear warning sonalerts are slightly recessed).  Does the pitch trim alert use the same sonalert as the autopilot?  And if so, how do I get my KFC 200 to make beeping noises if the sonalert is working...?

Link to comment
Share on other sites

For anyone interested in louder alerts for gear and stall warning, here are the part numbers. I used UC-09-628-S for stall warning and UB-09-628F(S)  for gear warning. Both of these have lower frequency tones and higher Dba. For me the difference is with noise cancellation headsets and engine running, I could not hear those warnings even though I tried new Sonalerts prior to installing the above two. But with these two the sound  comes through with ample volume to so that I hear them under all conditions

With respect to the AP alert, it comes on only under these conditions on my 1980 20J KFC200 as per the Flight Manual Supplement : Master switch on and trim toggle on produces a continuous tone. Depressing the push button test switch on the controller results in a several beeps along with the AP light flashing. With the Master switch, Avionics Master switch and Trim toggle on pulling the AP circuit breaker produces a continuous tone. There is no tone during normal operation after an AP disconnect wether commanded or uncommanded. Since this alert is not very useful I left the original Sonalet in place even though I can't hear it. I did not want to change it out because the AP test function resides in the computer. The louder alerts I am using  draw slightly more amperage and I thought this may damage the computer.

 

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.