Stuck cowl flap cable

[Jim Burns]

I've got a problem with a cowl flap cable in our Aztec.

The other day when landing, I opened the cowl flaps to 1/2 on final, then
full open after landing. I noticed when going from 1/2 open to full open
while on the ground the left cable seemed stiff. I tried closing the flap,
then reopening and it got worse immediately, then quit moving completely.

The flaps themselves move freely. I've disconnected the cable from the
torque tube on the flap end and it seems free, no binding, but I can only
pull or push the cable in or out 3/8-1/2 inch, just enough to make me
believe that it's not bound on that end. I've popped the covers off the
slide tubes on the cable and sprayed them with LPS 1. The slide tubes seem
free, they both spin around the cable easily.

Now I'm looking at the control handle end of the cable. I can not sense any
binding around the cable connector or in the slide tubes. I can not see
where the handle is binding or jammed but it will not budge. My next step is
to disconnect the handle from the cable. Then pull the cable out the bottom
of the belly to see if we can move the cable inside the sheath.

This all happened after we flew 5 hours from Atlanta, stopped for fuel, then
a short 20 minute flight to our home base. At the fuel stop the cowl flap
worked fine. Opened on landing, 1/2 closed after take off, full closed in
cruise, then opened to 1/2 at our home base with no binding noticed.

Any ideas?? Anybody ever have anything like this happen?

Thanks

Jim

[Michelle P]

Have you checked the pivot rod for the cowl flaps? they wear and bind.
Michelle

Jim Burns wrote:

>I've got a problem with a cowl flap cable in our Aztec.
>
>The other day when landing, I opened the cowl flaps to 1/2 on final, then
>full open after landing. I noticed when going from 1/2 open to full open
>while on the ground the left cable seemed stiff. I tried closing the flap,
>then reopening and it got worse immediately, then quit moving completely.
>
>The flaps themselves move freely. I've disconnected the cable from the
>torque tube on the flap end and it seems free, no binding, but I can only
>pull or push the cable in or out 3/8-1/2 inch, just enough to make me
>believe that it's not bound on that end. I've popped the covers off the
>slide tubes on the cable and sprayed them with LPS 1. The slide tubes seem
>free, they both spin around the cable easily.
>
>Now I'm looking at the control handle end of the cable. I can not sense any
>binding around the cable connector or in the slide tubes. I can not see
>where the handle is binding or jammed but it will not budge. My next step is
>to disconnect the handle from the cable. Then pull the cable out the bottom
>of the belly to see if we can move the cable inside the sheath.
>
>This all happened after we flew 5 hours from Atlanta, stopped for fuel, then
>a short 20 minute flight to our home base. At the fuel stop the cowl flap
>worked fine. Opened on landing, 1/2 closed after take off, full closed in
>cruise, then opened to 1/2 at our home base with no binding noticed.
>
>Any ideas?? Anybody ever have anything like this happen?
>
>Thanks
>
>Jim
>
>
>
>
>
>

[Jim Burns]

Yep, I unhooked the cable from the torque tube / pivot rod. The flaps, rod
connections, and pivot points all move freely.
Jim

[Frank Ch. Eigler]

Jim Burns wrote:

> I've got a problem with a cowl flap cable in our Aztec.
>
> The other day when landing, I opened the cowl flaps to 1/2 on final,
> then full open after landing. I noticed when going from 1/2 open to
> full open while on the ground the left cable seemed stiff. I tried
> closing the flap, then reopening and it got worse immediately, then
> quit moving completely. [...]

I've had to have one cowl flap cable replaced due to a stiffness
problem like this: apparently there was some severe corrosion or decay
of some other sort within the widget. In my case, the stiffness was
not getting worse, but the asymmetry concerned me. I recall hearing
of someone local severing similar cables outright by persistent
overpowering of stiff controls.


- FChE

[Jim Burns]

It's been suggested that we disconnect the ends from the cable then pull it
out of the sheath to check for corrosion. If the corrosion isn't to bad,
clean it up, and re insert the inner cable in the sheath using heavy oil as
a lube. Doesn't sound very fun. That cable resembles a very drunken snake,
the only direction it doesn't go is straight.
Jim

[Ben Jackson]

On 2005-03-23, Jim Burns > wrote:
> It's been suggested that we disconnect the ends from the cable then pull it
> out of the sheath to check for corrosion.

Whatever you do, don't force it. My mixture cable went from bad to worse
during a cold snap and I had enough leverage pushing on it to un-twist
the core and ruin the cable.

--
Ben Jackson
>
http://www.ben.com/

[Jim Burns]

A partner of mine is now working on the problem. He's got the cable
disconnected from the handle. The cable is loose and free and moves in and
out just fine, it's the HANDLE that is stuck! But he can't figure out how
to get the handle separated from the circular piece that pulls/pushes the
cable.
Jim

[Jim Burns]

So... after several of us spent several hours each standing on our heads
looking upside down at the interior of the fuel selector / cowl flap control
box, we finally figured out how to get the 40 year old aluminum cowl flap
handle out of the box.... use a hammer (ok a very small hammer).

Once we got it out, we figured out why it was bound up.... the machined
aluminum bushing and the machined aluminum hub simply chaffed together. The
clearance between the two was nearly non-existent and the chaffeing of the
soft aluminum locked the handle up tighter than heck. A little emery cloth
and some scotch-brite smoothed things up nicely. A small dab of moly grease
and everything went back together fine.

We're just glad we didn't have to change the cable.

Jim