KFC150 IN FLIGHT WOES

[N400YS]

Hi

 

Not so lucky this time.... Here is my new problem

 

My aircraft a M20J MSE 1995

 

1 month ago, during a climb, the autopilot KC192-KFC150 refused to engage though it passed the test on ground. I tried two times to re-test it and finally accepted to engage.

Next flight, test passed and after run-up refused to engage on the ground  and refused to pass the test again.

During an other flight, As I thought that the problem could came from a hot electronic, I poped the AP breaker during the climb and tried to test and to engage when leveled.....but failed!

I first cleaned the AP Red button and the trim switch with contact cleaner.

 

The test: 4 TRIM flash and then 5 bips.

 

When the "desease" shows up, the test refuses to give the 5 bips! and then impossible to light the FD, HDG or ALT indicators......

 

I read that it could come from a bad coil on the KI256 and I tried to test in flight with the Flight Director unplugged but no joy.....

 

Last test flight, I noticed that the AP failed immediatelly when airborne or when high rpm.....Impossible to pass the test when airborne.....But once on ground....the test passed! I

 

I know that the next step is my mechanic but do you have any advice for me

Thanks

 

Oliver "the loser"

 

 

Edited May 18, 2016 by N400YS

[carqwik]

Spray electrical contact cleaner into the trim switch on your yoke...(unscrew it from the yoke and give it a good cleaning).  

Mine would test ok on the ground and then go offline right after takeoff...even though the autopilot wasn't engaged at all.  Did this a few times...likely when I went to apply nose down trim.  IIRC, it would also sometimes take a few "tests" on the ground to get it to pass.  Having seen this problem before, I just cleaned the yoke trim switch and all was fine....Thankfully!!!

[N400YS]

4 minutes ago, carqwik said:

Spray electrical contact cleaner into the trim switch on your yoke...(unscrew it from the yoke and give it a good cleaning).  

Mine would test ok on the ground and then go offline right after takeoff...even though the autopilot wasn't engaged at all.  Did this a few times...likely when I went to apply nose down trim.  IIRC, it would also sometimes take a few "tests" on the ground to get it to pass.  Having seen this problem before, I just cleaned the yoke trim switch and all was fine....Thankfully!!!

Thanks Carqwik,

 

As the AP disengage switch if often the culprit, I thoroughly cleaned the AP Red button and the trim up-down switch....so, unfortunately, it seems not to be the solution....

 

Thank you for help :-)

[carqwik]

Call Autopilot Central in Tulsa, OK.. Describe the problem in exact details....they will suggest the proper course of action.  Don't waste your time with any local "experts" or avionics shops...BTDT  These guys are the experts on the King A/Ps...

[Awful_Charlie]

I've had something similar on two occasions now, and would love to get to the bottom of it

On both occasions:

1. The AP passed the test on the ground
2. This was after a short ground turnaround where on the previous flight it had been fine
3. The FD worked, but pressing the AP button failed to illuminate the light and it failed to take control
4. an 'in flight' press of the test button gave a never ending flashing AP light and beeps

On the last occasion, pulling the AP and AP Warn CBs, then resetting them a few minutes later, and then hitting the test button, the system passed the test and then functioned normally. I'm wondering if this might be a heat issue

I don't like doing the in flight test, as the pitch changes are a bit un-nerving for pax who don't necessarily understand what is going on

[N400YS]

1 hour ago, carqwik said:

Call Autopilot Central in Tulsa, OK.. Describe the problem in exact details....they will suggest the proper course of action.  Don't waste your time with any local "experts" or avionics shops...BTDT  These guys are the experts on the King A/Ps...

Unfortunately...I am in Europe.....Not in USA

[N400YS]

1 hour ago, Awful_Charlie said:

I've had something similar on two occasions now, and would love to get to the bottom of it

On both occasions:

1. The AP passed the test on the ground
2. This was after a short ground turnaround where on the previous flight it had been fine
3. The FD worked, but pressing the AP button failed to illuminate the light and it failed to take control
4. an 'in flight' press of the test button gave a never ending flashing AP light and beeps

On the last occasion, pulling the AP and AP Warn CBs, then resetting them a few minutes later, and then hitting the test button, the system passed the test and then functioned normally. I'm wondering if this might be a heat issue

I don't like doing the in flight test, as the pitch changes are a bit un-nerving for pax who don't necessarily understand what is going on

Quite the same indeed.

 

The test fails after the 4 TRIM flashes and never bips? Is there a meaning for that?

Is the number of flashes an indication of the system that fails?

 

Thanks

Edited May 18, 2016 by N400YS

[carqwik]

Even if you're in Europe you can still call Tulsa, OK... and they may give you a preliminary diagnosis on the phone.  When I told them my problems on the phone, they immediately thought they knew the problem....and turned out they were totally accurate as to the problem and the fix.  It's worth the call.

[Fritz Kaiser]

Hello Oliver,

where are you based?

There is one Autopilot-guru in Germany.

Call Martin Scheifl from Avionik Straubing. 

http://www.avionik.de/startseite.html

+49-9429-9424-0

(

He is the best one with King Autopilots.

good luck

 

Fritz

 

[LANCECASPER]

Sounds like the KC 192 Computer needs to be bench tested

[RobertE]

I agree with whomever suggested Autopilot's Central.  The best.  Honest too.

[N400YS]

On 19/05/2016 at 4:44 PM, Fritz Kaiser said:

Hello Oliver,

where are you based?

There is one Autopilot-guru in Germany.

Call Martin Scheifl from Avionik Straubing. 

http://www.avionik.de/startseite.html

+49-9429-9424-0

(

He is the best one with King Autopilots.

good luck

 

Fritz

 

Vielen dank Fritz....I will try shortly :-)

[N400YS]

On 19/05/2016 at 7:32 PM, LANCECASPER said:

Sounds like the KC 192 Computer needs to be bench tested

Indeed....

[N400YS]

Hi

 

I give  you news...after that, you will be autorized to call me "Stupid"

 

I put my KC192 computer to the avionic repairer....He found some light troubles in the FD circuit but nothing very serious. By the way he replaced all the unit buttons and lights because, according to him, problems come very often from worn contacts.

He told me to try again with the unit installed and to come back with the plane if the problem is still there.

 

So I installed back the unit and the problem was still there with something new: the bips that indicated that the test didn't pass were not audible anymore!!!

 

I bent over to the left side of the cockpit in order to switch off the avionics circuit......took support on the horn that turn a little and I heard the "bips" again!!! What the hell: it's a bad contact, I thought!!!

I caught the wires that are coming from the horn and began to try to figure from where came the problem.

 

In fact, it was a safety rotative plug that was almost completely unpluged.....Was pluged enough to make contact on the ground but when airborne, with the bank of the aircraft and the vibrations, it was slightly unpluged and caused bad contacts enough to put the autopilot on fault!

 

So my new first name: DUMB!  Second name: DUMBER!

 

Please before trying to sort an autopilot problem, don't be so stupid as I am, and check all the plugs under the panel

 

My 2 cents

[carusoam]

Great follow-up, Oliver!

Thank you and best regards,

-a-