Flap 0 error

[CTMI]

Every 8 or 10th time I select flaps 0 it flashes and nothing happens. Only flaps 0 does this, and it only happens going from -6 to 0, NEVER from 15 to 0. 

If it happens all I do is go back to -6 and "try again" so far that's always worked.

Any ideas? I attached a video of it. 

IMG_0876.MOV

[Roger Lee]

The potentiometer may just need to be programmed again. Just a refresh. It takes the two micro switches and is easy to do.

It may also just need the bullet connectors behind the panel pushed in and TWISTED to get a better contact.

[Anticept]

The rotary switch isn't making solid contact anymore.

Unfortunately unless you are familiar with electronics, it's not an easy fix.

[Roger Lee]

Ed,

Jeremy is here at Rotax school with me in Corona. From what he describes you may have a cracked circuit board or at least a solder joint.

[Anticept]

I had to fix this on two of ours already.

The rotary switches get corroded inside, and the contractor loses tension too. Jiggle the switch around without changing position and sometimes it starts working again.

If it DOESN'T resolve without switching position, then I'm with roger, you have a spotty connection.

[Runtoeat]

Can the rotary switch be cleaned/lubricated with a good contact cleaner/lube?  Is it accessible?  Please don't tell me the circuit board must be removed.......

[Roger Lee]

Jeremy said it's a wire that is soldered onto the circuit board.

[Runtoeat]

Roger, can you come up with any pictures of the circuit board while you're doing the class?  This is a lot cheaper than buying a plane ticket and attending!

[Anticept]

Those wires to the board would not affect the logic on only one position. They would affect several if not all.

Is it displaying an overload or error? This is a logic error and will be in the circuitry itself, needing repair or adjustment.

Do other flap positions lower than 0 have this problem? This would be a circuit error, including a loose wire.

The wires on the board are ground power, positive power, 5v excitement, sense, potentiometer ground, motor control ground, motor control up, motor control down on the older style.

Newer style has 15 wires. All the above plus 2 wires for the programming switch (instead of a board interface mini molex), plus 3 wires for manual signalling of motor up and down, and 3 wires for the two limit switches, and a shielding ground.

Also, failing potentiometers can cause this error as well. There might be a bad spot from -6 to 0.

I had a plane where the sense wire was shorting to the ground wire intermittently. It was right where the shielding was split off from the two conductors inside. I found it by moving the wires around while someone else moved the flaps.

[FlyingMonkey]

13 hours ago, Anticept said:

I had to fix this on two of ours already.

The rotary switches get corroded inside, and the contractor loses tension too. Jiggle the switch around without changing position and sometimes it starts working again.

If it DOESN'T resolve without switching position, then I'm with roger, you have a spotty connection.

If the switch takes a dump can it be disassembled and cleaned up, or does it need replacement?  I'm guessing a new switch from FD isn't cheap...

[CTMI]

Every other position works flawlessly, and it only happens when going from -6 to 0. Also, lets say i go from -6 to 0 and it faults (nothing happens) if i select 15, it will then go straight to 15 from -6, and all the other positions. Also, 0 flaps always works perfect as long as i'm going from 15 to 0.

Here's another thing. When i was making the video i was getting frustrated because i couldn't replicate it despite multiple tries. Then i turned off the main breaker and turned it on again and the fault happened again.

IF i turn off the main breaker and then turn it on again, the problem seems to happen on my first attempt.

Long story short, it only happens in one "direction" for one position.

[FredG]

When my flaps started failing due to a fractured soldered connection between a relay connector and the relay board foil conductor, it was intermittent and followed an odd pattern (it would occur only when deploying from 0 to 15 and then, when I returned the switch from 15 to 0 and reset to 15, it would almost always work).  Nothing about this suggested a broken connection, but when the failed solder connection was repaired, the fault was fixed.  

For diagnostic information, I connected a 12v pilot lamp in parallel with the flap motor to be sure that it was not failing to run when being energized.  In my case, as expected, the motor always ran when it got power.  I also replaced the position sensing potentiometer as a troubleshooting step which, given the actual fault, did not fix the problem.  

To make matters even more bizarre, the first step I took was to replace the circuit board on which the flap selector switch is located (with a used board from an owner parting out a CTsw) and reprogram the flap settings.  It worked perfectly in the hangar.  Then, I started the engine and it did not work.  At all.  No operation.  I switched the engine off and it worked perfectly.  I repeated this many times and it was repeatable (flaps worked perfectly with engine off, flaps didn't work at all with engine running).  I took a video to convince myself that this bizarre behavior was actually happening.  I installed the original flap selector switch board and it worked perfectly.  I have no explanation.  

The flap system is pretty complicated, IMHO.  I would be a bit careful about drawing quick conclusions from modest amounts of information about the pattern of failure.  

BTW, my airplane is registered E-LSA and I hold the inspection certificate for it.  I am NOT advocating any owner make repairs for which he/she is not qualified nor authorized to make.  I am not a LSRM nor A&P.  My experience is for your information, only.  

[CTMI]

Had a great conversation with Flight Design on this issue.

Interestingly enough they just recently diagnosed an SW with the exact same set of circumstances and they said the issue was that the -6 setting had to be reprogrammed. They didn't have to reprogram any other settings, just that -6 position and it fixed it. 

[Anticept]

7 hours ago, FlyingMonkey said:

If the switch takes a dump can it be disassembled and cleaned up, or does it need replacement?  I'm guessing a new switch from FD isn't cheap...

1300 to replace the board.

The switch is a very simple design, but is loaded with a ball and detent mechanism. It will fly apart on disassembly.

 

 

Glad to see the problem was solved with a simple reprogramming. I've done a lot of those too, but never had one act the way you had it, CTMI.

[Ed Cesnalis]

1 hour ago, Anticept said:

1300 to replace the board.

Dollars?

 

Board is $393 + tax and freight.

[Anticept]

That's not what the used to cost. Yes, 1,300 for the flap controller (old model). When I heard that, I repaired my own board switch.

[WmInce]

1 hour ago, Ed Cesnalis said:

Board is $393 + tax and freight.

Ed,

Who is that from?

Something tells me . . . it's in my future.

[Ed Cesnalis]

11 minutes ago, WmInce said:

Ed,

Who is that from?

Something tells me . . . it's in my future.

Flight Design 

[WmInce]

Thank you; Sir!

[FlyingMonkey]

Bill, are you having flap issues?

[WmInce]

1 hour ago, FlyingMonkey said:

Bill, are you having flap issues?

None at all . . . so far.

WRT, the flap control board, i wonder how much airframe vibration influences its life.

Personally (especially on the ground), I do everything possible to keep engine vibration to a bare minimum.