Ramifications of Cherokee Trim Jackcrew Failure

As I mentioned in a couple of other threads in RAP recently, the trim
jackscrew is very worn in our '74 Archer. The wear seems to be nearly half
of the thread depth. In other words, you can move the screw laterally
inside the drum about half of the height of a thread. It can be rocked
angularly inside the drum something like 5-7 degrees. Our A&P can't get to
it to replace it until mid July, so I'm trying to decide if we should ground
the plane, rush it done somewhere else, or wait until the next annual (nine
months). Our A&P tells us that he's never seen one fail, although he has
seen the cable break, which is pretty much of a non-event.

Of course, if the cable breaks, the trim is probably left stuck in some mid
position, not full up or down trim. I can see why this might not be
catastophic.

OTOH, a failure of the jackscrew itself might result in the trim slipping
all the way to full up or down, and this might be more difficult to deal
with. I've never tried to fly with trim at the extremes, so I don't really
know how much effort is needed to stay in control. I know we can just try
it, but that will put more stress on the jackscrew, so I'm not sure I want
to run the experiment on this airplane. Anyone out there with a Cherokee
want to run the experiment for me and let me know what you find?

Another possible failure mode is for the screw to strip so badly that some
or all antiservo function of the tab is lost. This could result in extreme
difficulty in controlling pitch. Anyone have thoughts on how bad this might
be? I have trouble imagining the screw stripping rapidly to the point that
the screw could slide freely up and down inside the drum, but it might be
possible. How can we find out how bad this would be? Is the antiservo
function essential for flight control, or is it just to improve the "feel"
of the controls?

An final concern is that with the extreme looseness we have now, the flutter
margins might be significantly compromised. Stabilator flutter could
certainly result in catastrophic failure modes! This is another potential
ramification of flying with it in the current state. Any thoughts on how to
research this possibility?

Finally, are there other failure modes I haven't though of? Anyone think
that this can wait until the annual? I'd love some thoughts. I have a lot
of respect for you folks, although I realize that free advice is worth just
what I paid for it. Thanks.

--
Bob (Chief Pilot, White Knuckle Airways)

I don't have to like Bush and Cheney (Or Kerry, for that matter) to love
America