Tony, probably I was the first person to suffer tailplane bush disbonding and
that
was before the sad accident which killed two guys in Wales, giving rise to
mod 73 and the mod to strengthen the security of wing root pins. I can't
remember
how the lay-ups were done with the bid when I made my own approved repair,
nor when I had to repeat the process on both tailplanes after the mods were
introduced. Too long ago!
One thing became known at that time, which was that some people had enlarged the
tailplane pip-pin recesses to their own requirements to do things like fitting
flush and easily removable covers to the recesses. What this did in some cases
was to increase the distance between the pip-pin head and the recess inboard
sidewall, which would allow the tailplane to migrate off the drive pins if
ever a bush disbonded again.
Being ultra-cautious in such matters, I decided to create another line of
defence
by cutting and shaping little pieces of plywood to neatly fit the gap between
the pip-pin heads and inboard sidewalls and bonded them in place with
resin+flox.
Thus there is no possibility for the tailplanes to migrate off the drive
pins in the even of a disbond, provided that the pip-pins are in.
To cover over the recesses in the tailplane tops, I use white adhesive tape.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=466642#466642
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