In article ,
Peter Thomas wrote:

The ASW 20 has instructions to nock the fuselage pins
out and put shims behind them to remove slack, apparently
to prevent the fuselage fishtailing. The Hornet and
Club Libelle i fly both have external shims on the
fuselage pins, they would have a lot of slack otherwise.
manufacturer maintenace manual should advise

Pete

I think external shims on Libelles are common. Both my 301 Libelles had
shims on the pins.