Cessna flap relay

To answer your questions:

1. I've had the plane for about 5 months. The flaps worked fine when I got it and fine up until about a month ago.
2. After the annual inspection, they worked fine also. The problem started about three months after the annual. The jackscrew was inspected and lubed per the AD. Otherwise no maintenance was performed on the flaps/ actuator.
3. They stop at any setting or in-between any particular degree range. They have stopped at about 3 degrees, 10 degrees, 20 degrees and 30 degrees. This happens whether they are going down or up. It is really totally unpredictable.
4. They have stopped in the air and on the ground. Notably though, during checks on the ground, they have been just fine, but then stopped while in the air and on approach. Jim is correct, I tested them very extensively on the ground with no issues after checking connections and such. Then in the air, they stopped on the second approach. At that point, they were all the way up. They have stopped after landing several times now, and I couldn't put them back up until I got parked and tinkered a little. Then they worked again. When I say tinker, I mean knocking on the bottom of the wing...even tapping on the wing worked several times.
5. I haven't tried to have someone apply a load to them on the ground. I have had help when they stopped by having someone apply light pressure to the flap, at which time it started again.
6. On the ground, the motor sounds fine and works great. There is no grinding or binding that I can detect. When they are working, the flaps are very smooth operating.
7. The wiring is all in-tact and in good shape.
8. The flaps are on a dedicated 35A slow-blow fuse. The fuse is in good shape as is the holder and contacts inside the holder. All is clean as well. There is nothing else wired to this fuse.
9. N/A on the next one....It is dedicated. Thus far, no other failures of any kind.
10. I did remove the fuse and all is good and clean.
11. Fuse holder and wires are in good shape. Contacts in the fuse holder are in good shape.
12. I haven't inspected any wires or plugs in the wing root as of yet.
13. I did not solder the connections. I tend to agree with Jim on that point.

I went back out tonight. When the flaps stopped the other day, they were full-up and couldn't be put down. So, I pulled the inspection plate underneath the motor. I VERY, VERY LIGHTLY wiggled the wires that come out of the back of the motor, at the point where the plastic connector is located. Tried the flaps and they worked. Cycled them several times and they stopped again at about 35 degrees. Then I lightly wiggled with wires at the base of the motor. They worked again. I cycled them several more times throughout the entire range and they worked fine again. Seems like maybe a loose wire inside the motor or maybe a fouled up ground. Any thoughts? I'm going to try to get video of it and submit here at some point. Just kinda hard to do at night.

By the way, I work third shift so, sorry for the late replies. Again, I appreciate all of the responses and help in figuring this out!
 
bnt83 said:
Its a good thing Jim is a stubborn old koot because a young guy would have run the other way by now.
Click to expand...

Not only is he old and stubborn but a hell of a proofreader. That would be MR. COOT, to you sir. (And yes, that is the correct spelling of "coot".)

:goofy:'


Jim
 
SPAJC said:
I went back out tonight. When the flaps stopped the other day, they were full-up and couldn't be put down. So, I pulled the inspection plate underneath the motor. I VERY, VERY LIGHTLY wiggled the wires that come out of the back of the motor, at the point where the plastic connector is located. Tried the flaps and they worked. Cycled them several times and they stopped again at about 35 degrees. Then I lightly wiggled with wires at the base of the motor. They worked again. I cycled them several more times throughout the entire range and they worked fine again.

I'll go to Reno with $100 on worn brushes or dirty commutator. Anybody want to cover me?

By the way, I work third shift so, sorry for the late replies.

I teach second shift in the local community college. No "sorry" necessary; I completely understand coming home at midnight and sleeping until 9 or so.
Click to expand...
.....
 
SPAJC said:
To answer your questions:

1. I've had the plane for about 5 months. The flaps worked fine when I got it and fine up until about a month ago.
2. After the annual inspection, they worked fine also. The problem started about three months after the annual. The jackscrew was inspected and lubed per the AD. Otherwise no maintenance was performed on the flaps/ actuator.
3. They stop at any setting or in-between any particular degree range. They have stopped at about 3 degrees, 10 degrees, 20 degrees and 30 degrees. This happens whether they are going down or up. It is really totally unpredictable.
4. They have stopped in the air and on the ground. Notably though, during checks on the ground, they have been just fine, but then stopped while in the air and on approach. Jim is correct, I tested them very extensively on the ground with no issues after checking connections and such. Then in the air, they stopped on the second approach. At that point, they were all the way up. They have stopped after landing several times now, and I couldn't put them back up until I got parked and tinkered a little. Then they worked again. When I say tinker, I mean knocking on the bottom of the wing...even tapping on the wing worked several times.
5. I haven't tried to have someone apply a load to them on the ground. I have had help when they stopped by having someone apply light pressure to the flap, at which time it started again.
6. On the ground, the motor sounds fine and works great. There is no grinding or binding that I can detect. When they are working, the flaps are very smooth operating.
7. The wiring is all in-tact and in good shape.
8. The flaps are on a dedicated 35A slow-blow fuse. The fuse is in good shape as is the holder and contacts inside the holder. All is clean as well. There is nothing else wired to this fuse.
9. N/A on the next one....It is dedicated. Thus far, no other failures of any kind.
10. I did remove the fuse and all is good and clean.
11. Fuse holder and wires are in good shape. Contacts in the fuse holder are in good shape.
12. I haven't inspected any wires or plugs in the wing root as of yet.
13. I did not solder the connections. I tend to agree with Jim on that point.

I went back out tonight. When the flaps stopped the other day, they were full-up and couldn't be put down. So, I pulled the inspection plate underneath the motor. I VERY, VERY LIGHTLY wiggled the wires that come out of the back of the motor, at the point where the plastic connector is located. Tried the flaps and they worked. Cycled them several times and they stopped again at about 35 degrees. Then I lightly wiggled with wires at the base of the motor. They worked again. I cycled them several more times throughout the entire range and they worked fine again. Seems like maybe a loose wire inside the motor or maybe a fouled up ground. Any thoughts? I'm going to try to get video of it and submit here at some point. Just kinda hard to do at night.

By the way, I work third shift so, sorry for the late replies. Again, I appreciate all of the responses and help in figuring this out!
Click to expand...

Still the same suspicions as before, worn brushes, carbon dust, arced commutator.
 
Still, some speaker wire to a 12 volt battery and run the flaps up and down would be super easy to confirm it's the motor.

Note to everyone else: Do not attempt this on a newer plane that doesn't have the overrun slip type drive. Bypassing limit switches could prove costly.
 
Jeff a doctor spends the first few minutes trying to get the full picture, in a forum it's usually one or two good questions per post and a clear story is difficult to see. That paragraph you wrote is much more telling than the bits and pieces that show up prior to it.
 
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