I'm going to guess that the 10,000 repetitions of
opening and closing the dive brakes were what really caused the
bellcrank problem in this case. On the other hand, I'm
not a dig fan of manhandling and potentially
deforming the spoilers on the glass ships either.
If I was smarter and I owned my own ship, I'd
likely investigate the best places to apply pressure which
would't damage anything even when repeated 10000 times...

In article ,
Chris Nicholas wrote:
Mark James Boyd wrote: [snip] " . . . during a PCC a bellcrank broke and
this was caused by the pressure exerted by the "helper."
Nice to have this happen on the ground, and I can't
think of how this could have been detected without
a PCC. So now I think a PCC is useful too..."

Having a helper exert this much force is good???

How much is too much? There's really no manual for this, and
the POH doesn't even mention PCC... This area could
use a bit of advice from sailplane manufacturers/materials
engineers...


I retain my renegade attitude to PCC's - they may be suitable for some
things if done right (and breaking gliders is not doing it right in my
book - the above is not an isolated example) but other checks are far
more useful, and less damaging, for some gliders, e.g. my Ka6E.
--

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Mark Boyd
Avenal, California, USA