Extra 300LT - Repair of Reinforced Glass and Carbon Fibre Components; Repairs

CHAPTER 51
PAGE 22
PAGE DATE: 7. July 2010
MAINTENANCE MANUAL EXTRA 300LT
51-70-00 REPAIRS
51-70-01 Repair of Reinforced Glass and Carbon
Fibre Components
I M P O R T A N T Repair of composite parts has to be carried out only by
qualified and authorized personnel.
If the aircraft is damaged, proceed as follows. First conduct
a careful visual inspection of the surface and the damaged
area. Frequently, the damage extends to futher components,
sometimes a fracture will continue invisibly beneath the
surface.
Perform the repair work with utmost care. The external shell
of the wing and empennage is stressed; a failure of this
bonded structure can lead to an aircraft crash. In order to
eliminate dangerous stress concentrations, avoid changes in
cross-sectional areas.
I M P O R T A N T The resin-hardener mixture ratio must be precisely
maintained (+0.5%). Clean cups and tools must be used.
The weight ratio of glass fabric to resin mixture should
be approximately 50:50.
Immediately prior to applying the wet laminate, sand and
vacuum clean the repair area, so that no dirt and dust could
prevent a secure adhesion.
W A R N I N G Sanding carbon and glass fibre laminates emits a fine
dust that may cause skin and/or respiratory irritation
unless suitable skin and respiration protection is used.
W A R N I N G Carbon-tetracloride or Acetone used for cleaning re-
pair areas are flamable liquids and should be used with
proper ventilation and safety equipment.
I M P O R T A N T As with plywood grain, the direction of the various fi-
bres (longitudinal or diagonal) is of great importance
for the stability.