iKarus C42C Maintenance Manual

COMCO IKARUS
Maintenance Manual C42 Series
MaintenanceManual C42-
Series_Issue_VII_18.02.2014.doc
Revison No.:1 49 from 107
− Since screws and nuts, and particularly those made of stainless steel tend
to stick, machinery grease must be used during assembly.
− At least two turns of thread of the screw must be visible outside the nut to
ensure a proper safety function.
− Generally, the screws are installed from top to bottom and from front to
back. In some places, however, this is not possible due to design and/or
assembly reasons. The installation method found in the aircraft must
always be maintained.
− For compact screw connections, the usual torque values used in
mechanical engineering must be used (e.g. M8  25 Nm; M6  12 –15
Nm).
− Exceptions are the screw joints of aluminium tubes. Although plastic shoes
are used, the tubes would buckle beyond limits. In these cases the screws
may only be torqued up to an elastic strain of a maximum of 3% of the tube
diameter.
− In the case of screw connections with plastic parts, large over-sized
washers are used for better induction of the load. When repairs are done
on such parts, these washer must be employed again.
− If blind thread boreholes are used instead of nuts in screw connections,
safetying is either done by using lock washers (e.g. propeller bolts of
WarpDrive propellers), locking plates (e.g. torsion tube) or in a lot of cases
anaerobic screw safetying fluid (e.g. Loctite medium).
Safety washers may only be used once. To ensure proper protection
against corrosion, only stainless steel washers are used.
− In the C42 counter nuts are also used as a means of securing screw
connections. Especially when used in the control system, counter nut
safetying permits adjustments to control surfaces and flap deflections. Red
safety varnish secures the nuts further and also allows a quick visual
inspection.
− Screws which have been secured with Loctite and then loosened must be
cleaned thoroughly before being used again (Loctite cleaning spray) to
ensure that the screw connection remains secure when Loctite is applied
again.

iKarus C42C Specifications

General

Brand	iKarus
Model	C42C
Category	Aircrafts
Language	English