Cessna T188C - Page 392

MODEL
188 &
T188 SERIES
SERVICE MANUAL
mance
are
instructions
for
repair
of
tubular
members,
Service
Department.
Figure
17-11
lists
the size
and
including
cluster
repairs,
split-sleeve
reinforce-
wall
thickness
of each
tube
used
in
the
structure,
ments,
welded-patch
repairs,
splicing
by
inner
along
with size
and
wall
thickness
of
repair
tube
for
sleeve
method,
splicing
by outer
sleeve
method
and
each.
Structural
alignment,
shown
in
figure
17-1,
splicing
by using
larger diameter
replacement
tube.
must be maintained.
17-68. NEGLIGIBLE
DAMAGE.
Negligible damage
NOTE
of fuselage
tubing
should
be limited
to small
smooth
dents,
shallow scratches,
and minor
bowing of
tub-
Refer to Section
18 for required
priming after
ing, not in the middle
third of the tube.
a welded repair
has been accomplished.
17-69.
REPAIRABLE
DAMAGE.
Dents at
a cluster
17-71.
ENGINEMOUNT.
may
be repaired
by a finger
type
welded
patch.
Dented,
cracked,
or otherwise
damaged
tubes
may
17-72.
DESCRIPTION.
The mount
for
the
aircraft
be
repaired
by
a welded
split-sleeve
reinforcement,
engine
is constructed
of
4130
chrome-molybdenum
after
straightening
the
damaged
part
and stop
drill-
teel tubing.
A truss
structure,
fastened
to the
fire-
ing
cracks
with
a No.
40 (.98)
drill.
Dents
or
holes
wall at
four
points,
supports
a
cradle
arrangement.
in
tubes which
are
not in
the middle
third
of the
tube
This
cradle
arrangement,
with its
supporting
lugs,
and do
not result
in the
patch overlapping
a joint
may
forms
the
base for
rubber
shock mounted
engine sup-
be repaired
by a welded
patch,
one gage
thicker,
if ports.
Enne
mounts
are illustrated
n figure
17-12.
the dents are not deeper than one-tenth of the tube
diameter,
do
not involve
more
than
one-fourth
of the
GENERAL
CONSIDERATIONS.
All welding
tube
circumference,
and are not
longer than the
tube
diameter;
if dents are free from cracks,
abrasions on the engine
mount should be of the highest
quality
and
sharp corners;
and
If the dented
tubing
can be
since
the tendency
of vibration
is
to accentuate
any
substantially reformed without
cracking can be ap-
minor defect present and cause
fatigue cracks. En-
plication
of
the patch.
Holes must
cracking be ore ap-
gine mount
members
are preferably repaired
by using
a
large
diameter
replace
must
not
be,
telescoped
over
tube diameter
must not
involve more than
one-
the stub of the
original member
using fishmouth
and
fourth
of
tube
circumferencerosette
type
welds.
However,
reinforced
30-degree
17-70. DAMAGE
NECESSTATING REPLACEMENT
scarf welds in
place of the fishmouth welds
are con-
sidered satisfactory for engine mount repair work.
OF
PARTS. If extensive
damage
has occurred,
it is
recommended
that the
complete
fuselage
tubular
17-74.
ENGINE
MOUNT
SUPPORT
CRADLE
DAM-
structure
assembly
be replaced.
Where
damage
ex-
AGE. Minor
damage
such as
a crack adjacent
to
an
ceeds
that
specified
as negligible
or repairable,
par-
engine
attaching
lug
may
be repaired
by
rewelding
tial
replacement
is required.
Three
methods
of
the cradle
tube
and extending
a gusset
past
the dam-
splicing
in partial
replacement
tubes
are acceptable,
aged area.
Extensively
damaged
parts
should
be re-
all
of which
are
standard
procedures
outlined
in
placed.
Federal Aviation
Regulations,
Part 43. Splicing
by
the
inner
sleeve
method
is
recommended
where
a
17-75.
DAMAGE
INVOLVING
ENGINE
MOUNTING
smooth
tube
surface
is
desired.
Splicing
by using
LUGS
AND ENGINE
MOUNT
TO
FUSELAGE
ATTACH-
a larger
diameter
replacement
tube requires
the
ING
FITTINGS.
Engine
mounting
lugs
and engine
least
amount
of cutting
and welding,
but cannot
be
mount
to
fuselage
attaching
fittings
should
not
be re-
used
where
the
damaged
tube
is cut
too
near
adjacent
paired
but
should
be
replaced.
clusters or
where brackets
and the like
require the
same
size
tube.
Splicing
by the outer
sleeve
method
17-76.
BAFFLES
ordinarily
should
be replaced
if
requires
the
greatest
amount
of welding
and
should
damaged
or cracked.
However,
small
plate
rein-
be used
only
where
the
other
splicing
methods
are
forcements
riveted
to
the baffle
will
often
prove
not
suitable.
If
it should
become
necessary
to
re-
satisfactory
both to
the strength
and cooling
require-
pair a major
attach
point fitting,
consult
the Cessna
ments
of the
unit.
SHOP NOTES:
17-30