Mooney Eagle Flap problem

[Chris K]

I could use some help trying to figure out why my flaps are not working.  My plane just got out of annual and I noticed my right flap was slightly loose (like someone walked on it ).  My mechanic said not to worry about it and he'd fix it later - he sent me for a test flight to make sure everything else ok.  I landed once at nearby airport to fuel up, flaps work fine then. When I returned, flaps decided not to work at all (coincidence when flying with slightly loose flap?).

We have gone through the system and checked motor (works fine when powered outside of system),  we suspected the 2 Aromat relays which have been replaced but flaps still don't work.  I tested the micro position switches and depending on the flap switch position and micro-switch position, I seem to be getting either a reading of no voltage or an odd variable voltage reading - is that how those switches work or is the variable voltage an indication the switches need to be replaced?  The front (down) limit switch seems to check ok.  Rear (up) limit reads zero volts which I assume would be correct since flaps are up, or should they be energized in order to complete the circuit when flap switch is set to down?   

Any help would be greatly appreciated.

[Yetti]

Generally limit switches close/complete circuit to reverse the circuit.    Clean and exerciser limit switches with contact cleaner.   Assuming relays are good.   there is a thread here about the relays replacement.

[Yetti]

 

[Chris K]

3 minutes ago, Yetti said:

 

I did see this thread.  We changed the relays and the micro-switches are both on the contact wheel.  Both my flaps are tightened back up and does not matter if I try cycling the flaps with the micro-switches off the contact wheel or off.  I did notice when off the plane, one of the micro-switch contacts seem to extend out a but further than the other.  Could that be what the OP of that thread was referring?  Seems like the switch is either on or off (clicks in or out).

 

[Yetti]

yes limit switches are off or on.   Could the droopy flap be causing the limit switch to engage?   Do you the 3 flap position type switch in the cockpit?   I think the droopy flap bent things.  There is one tube that controls both flaps equally.   Posting pictures is your next step.

Edited July 23, 2019 by Yetti

[larryb]

The voltage readings should be 0 or battery voltage. But sometimes it is hard to get a good reading due to surface corrosion where you are taking the measurement. A good sharp tip helps.

[Chris K]

43 minutes ago, larryb said:

The voltage readings should be 0 or battery voltage. But sometimes it is hard to get a good reading due to surface corrosion where you are taking the measurement. A good sharp tip helps.

I get that on the rear limit switch (yet to remove front limit to test, but did douse with contact cleaner to no avail). The micro-switches for partial flaps are all over the place, either 0 when open but when circuit closed, the voltage is all over the place and not constant.  I used contact cleaner all over all the switches.   If the micro-switches are not supposed to be variable, seems they are the culprit?  Could that be the "relay chatter" from this thread? 

 

[Chris K]

20 hours ago, Yetti said:

yes limit switches are off or on.   Could the droopy flap be causing the limit switch to engage?   Do you the 3 flap position type switch in the cockpit?   I think the droopy flap bent things.  There is one tube that controls both flaps equally.   Posting pictures is your next step.

The droopy flap has been adjusted back to where it should be.  I do have the 3 flap type switch in the cockpit which tests ok. 

Here is a photo of the micro-switches - hard to see but the upper one extends off of the red clicker switch by a bit.  Also including a picture of the limit switches before I doused with contact cleaner to see if it would help.

[larryb]

The switches are pretty well sealed, so contact cleaner isn’t going to do much. Check out my schematic in the other thread to see how it works. The chatter has to do with the adjustment of the micro switches.

[EricJ]

8 minutes ago, larryb said:

The switches are pretty well sealed, so contact cleaner isn’t going to do much. Check out my schematic in the other thread to see how it works. The chatter has to do with the adjustment of the micro switches.

Contact cleaner does help the micro switches.    Liberal squirting in the orifices around the switch plunger does help, especially if it's been dirty.    They're not hermetic, which is the problem.   Crap gets in and just stays there.

[Chris K]

2 minutes ago, larryb said:

The switches are pretty well sealed, so contact cleaner isn’t going to do much. Check out my schematic in the other thread to see how it works. The chatter has to do with the adjustment of the micro switches.

I did see that.  Thank you kindly for creating the schematic.  I'm guessing when I had one sagging flap is when the chatter occurred and why we went ahead and replaced the relays.  I tried running the flaps with the micro-switches operated by hand just to make sure there was no adjustment issue and no joy.  I'm suspicious whether the micro-switches were also somehow affected and need replacing due to the variable voltage output when circuit is closed?  I tested continuity in the circuit board after relays were replaced and get continuity everywhere - most solders were 0 ohms except for one pair that measured about 4 ohms but I'm guessing that circuit went through a resistor, so solders and circuit board otherwise seem all fine).   I could not find the micro-switches on Lasar's webpage - if not expensive and available, do I simply replace?  My regular mechanic who otherwise is a good engine guy, but not a Mooney guy is telling me it's going to cost a lot of AMU's to "troubleshoot" the issue which I'm not happy about, especially since someone at his shop is the one that damaged my flap in the first place.

[Yetti]

I can't make out the part numbers.   Digikey.com should get you the switches.    If you look on the end with two terminals.   It says NO and NC.    One of the wires is connected to the NC  so it would be passing current till the plunger is pushed.

 

Just correcting my earlier statement.

If you are bench testing....  sometimes a light bulb with aligator clips makes it easier than a VOM.   Few minutes with a soldering iron will get you going with a bulb.

[alextstone]

My regular mechanic who otherwise is a good engine guy, but not a Mooney guy is telling me it's going to cost a lot of AMU's to "troubleshoot" the issue which I'm not happy about, especially since someone at his shop is the one that damaged my flap in the first place.

Wait, what?? Are you sure your regular mechanic caused the problem? If so, why not insist they fix it at their expense? If there is resistance, kindly offer to have another shop handle the fix and forward the bill to their insurance company. That should create some motivation to make you whole.

Sent from my Pixel 3 XL using Tapatalk

[Chris K]

Just now, alextstone said:

 

 

Wait, what?? Are you sure your regular mechanic caused the problem? If so, why not insist they fix it at their expense? If there is resistance, kindly offer to have another shop handle the fix and forward the bill to their insurance company. That should create some motivation to make you whole.

Sent from my Pixel 3 XL using Tapatalk
 

I'm getting pretty close to that but don't want to go there quite yet.  He is insisting the droopy flap did not cause my flaps to completely stop working which is why I'm working hard to get to the bottom of this and I figured there must be some expertise here on this board that would help pinpoint what is going on.  I'm thinking the droopy flap messed with the contact on the TO position micro-switches but seemingly something other than the relays were affected since changing them did not help.  If someone could confirm the micro-switches should read 24v and not variable voltage, could the simple micro-switch have somehow shorted inside?  Note that the variable voltage seems to go in a loop with a very quick increase (or decrease but don't recall) in voltage, a very brief O.L. indication and then a new loop of increasing voltage again and the loop is very consistent.

[Yetti]

The limit switches just switch. so 24 volts. No resistance should be in the switch.  You could have a dead battery in your VOM.   or possibly a failing diode.   I saw one on the board.

[Chris K]

55 minutes ago, Yetti said:

The limit switches just switch. so 24 volts. No resistance should be in the switch.  You could have a dead battery in your VOM.   or possibly a failing diode.   I saw one on the board.

OK, good eyes Yetti.  I did not look closely at the board and thought those were resistors.  I'll check those next.

[PT20J]

If I were troubleshooting this, I’d start by understanding mechanically exactly what caused the right flap to be “slightly loose” and exactly what was done to fix it. The mechanical design is not robust. Limit switches are connected to the mechanical system. Could be something got bent. Anyway, I’d eliminate that possibility first. 

[Chris K]

22 hours ago, PT20J said:

If I were troubleshooting this, I’d start by understanding mechanically exactly what caused the right flap to be “slightly loose” and exactly what was done to fix it. The mechanical design is not robust. Limit switches are connected to the mechanical system. Could be something got bent. Anyway, I’d eliminate that possibility first. 

Absolutely - though my mechanic seemed to believe the damage was limited to the heim bearing we simply tightened the adjuster to get the dragging flap back up.  Needless to say, I'm suspicious of this type of repair and although he claimed he'd repair the bearing in the future he has now made himself rather scarce.  My non certified mechanic eyes have not yet found any other damage other than seemingly either the mentioned adjuster rod or the heim bearing so I mechanically believe were fine on the limit switch contacts.  What does amaze me is that our Mooney airframe has only this one small connecting rod per flap that moves our flaps up and down and keeps it in place.  This is my second Mooney and I always make sure no one ever steps on my flaps because of this reason.  Whoever did step on it had no business being on the airplane and either a non pilot or was accustomed to planes with a wing walk on the flaps - No Step really means No Step on a Mooney.

[Chris K]

On 7/23/2019 at 9:19 PM, Yetti said:

The limit switches just switch. so 24 volts. No resistance should be in the switch.  You could have a dead battery in your VOM.   or possibly a failing diode.   I saw one on the board.

So the diodes with power off on the plane did show a trace bit of voltage (between 4 to 7 milli-volts) going in the wrong direction.  With the power on, the voltage was all over the place in both directions.  Seems to me they are toast?   They are 1N4004 diodes (zoom on picture below) - with that diode number, anything else special to ensure I replace with correct ones?  Though I doubt this could be the only culprit since not really short circuited - I would think there would still be an intermittent circuit connection that would generate some motor activity?

[Yetti]

Diodes have one job to do.   A permanent magnet motor runs forward and backwards based on how the B+ and ground are applied.  Page 6 has a gear schematic that looks similar to your relays.  I bet the number on the wires will be the same. 

http://mooney.free.fr/Manuels M20J/M20J/Mooney Service Manuel M20J Vol. 2 of 2.pdf

https://www.amazon.com/1N4004-Axial-Silicon-Rectifier-Diodes/dp/B008LTJOX6

Get the numbers off the relays and just replace them too.

 

Edited July 26, 2019 by Yetti

[PT20J]

The flap system is pretty simple. It comprises a motor, a control panel switch, some relays to reverse direction and some limit switches. In this application, the diodes are“flyback” diodes placed across the relay coils to snub out the induced voltage when current is cut from the relay. The 1N4004 diode was(is) a common general purpose diode. It’s rated at 1A forward current and 400V reverse voltage. It is very unlikely to be the source of your problem. Since the motor bench checks OK, it most likely is either a relay or micro switch. 

Edited July 26, 2019 by PT20J

[carusoam]

Summary...

1) there is a problem that is not electronic in nature...

2) there is an electronic problem as well....

3) there aren’t any Mooneys that have independently operating flaps... at least not designed to have one loose or droop without the other...

There is something wrong with that.  It should be pretty easy to find... then look for what bent or broke to allow the independent flaps to happen...

Flying with a loose flap is a no go for me... that would be an uncontrolled control surface... 

Your mechanic sent you to test fly the plane in a condition that seems less than optimal?  That seems a bit il-advised?

Lets not repeat the test flights until the control surfaces are proven to be behaving as designed...

would a flap be considered a control surface?

lets call it a controllable wing surface... either way... a split deployment of flaps is an emergency... the airlerons May be  designed to overcome such a situation...

The outcome of the flight has terrible limitations...

PP thoughts only, not a mechanic...

best regards,

-a-

[Chris K]

16 hours ago, carusoam said:

Your mechanic sent you to test fly the plane in a condition that seems less than optimal?  That seems a bit il-advised?

Lets not repeat the test flights until the control surfaces are proven to be behaving as designed...

would a flap be considered a control surface?

lets call it a controllable wing surface... either way... a split deployment of flaps is an emergency... the airlerons May be  designed to overcome such a situation...

 

best regards,

-a-

Agreed, please don't get the impression my plane is leaving the safety of it's hangar until everything is re-checked properly and no stone is left unturned. 

[carusoam]

Chris,

I have a tendency to overstate some mechanical safety items... or same them at least twice...

Somethings I have done early in my flying career... I thought we’re normal and everyone was doing it...

 

If somebody on CessnaSpace said don’t do that... I would have been surprised... then wouldn’t have done that!   

Probably would have taken saying it twice for me to understand...

Best regards,

-a-

[Cyril Gibb]

On 7/25/2019 at 5:46 PM, Chris K said:

So the diodes with power off on the plane did show a trace bit of voltage (between 4 to 7 milli-volts) going in the wrong direction.  With the power on, the voltage was all over the place in both directions.

Note that when 1 relay is engaged to apply power to the flap motor, the other relay is providing the ground to the motor via its normally closed position.  When I had a flap issue, it was one of the relays that had an intermittent (high resistance) normally closed contact.  Something to check.