Wing Leading Edge - Cessna 150 STANDARD Service Manual

18-41. WING LEADING EDGE.
18-42. NEGLIGIBLE DAMAGE. Refer to paragraph
18-13.
18-43. REPAffiABLE DAMAGE. A typical leading
edge skin repair is shown in figure 18-9. An epoxy-
type filler may be used to fill gaps at butt-joints.
To facilitate repair, extra access holes may be in-
stalled in the locations noted in figure 18-11. If the
damage would require a repair which could not be
made between adjacent ribs, refer to the following
paragraph.
18-44. DAMAGE NECESSITATING REPLACEMENT
OF PARTS. For extensive damage, complete lead-
ing edge skin panels must be replaced. To facilitate
replacement, extra access holes may be installed in
the locations noted in figure 18-11.
18-45. ELEVATORS AND RUDDER.
18-46. NEGLIGIBLE DAMAGE. Refer to paragraph
18-13. The exception to negligible damage on the
elevator surfaces is the front spar, where a crack
appearing in the web at the hinge fittings or in the
structure which supports the overhanging balance
weight is not considered negligible. Cracks in the
overhanging tip rib, in the area at the front spar
intersection with the web of the rib, also cannot be
considered negligible.
18-47. REPAIRABLE DAMAGE. Skin patches
illustrated in figure 18-4 may be used to repair skin
damage. Following repair, the elevator s and rudder
must be balanced. Refer to paragraph 18-49 and
figure 18-3 for balanCing the elevators and rudder.
If damage would require a repair which could not be
made between adjacent ribs, see the following para-
graph.
18-48. DAMAGE NECESSITATING REPLACEMENT
OF PARTS. If the damaged area would require a re-
pair which could not be made between adjacent ribs,
complete skin panels must be replaced. Ribs and
spars may be repaired, but replacement is generally
preferable. Where extensive damage has occurred,
replacement of the entire assembly is recommended.
After repair and/or replacement, balance elevators
and rudder in accordance with paragraph 18-49 and
figure 18-3.
18-49. ELEVATOR AND RUDDER BALANCING.
Following repair, replacement or painting, the ele-
vators and rudder must be balanced. Complete in-
structions for fabricating balancing fixtures and
mandrels and their use are given in figure 18-3.
18-50. FIN AND STABILIZER.
18-51. NEGLIGIBLE DAMAGE. Refer to paragraph
18-13.
18-52. REPAffiABLE DAMAGE. Skin patches illus-
trated in figure 18-4 may be used to repair skin
damage. Access to the dorsal area of the fin may be
gained by removing the horizontal closing rib at the
18-4
bottom of the fin. Access to the internal fin structure
is best gained by removing skin attaching rivets on
one side of the rear spar and ribs, and springing
back the skin. Access to the stabilizer structure
may be gained by removing skin attaching rivets on
one Side of the rear spar and ribs, and springing
back the skin.
If
the damaged area would require a
repair which could not be made between adjacent
ribs, or a repair would be located in an area with
compound curves, see the following paragraph.
18-53. DAMAGE NECESSITATING REPLACEMENT
OF PARTS.
If
the damaged area would require a
repair which could not be made between adjacent ribs,
or the repair would be located in an area with com-
pound curves, complete skin panels must be replaced.
Ribs and spars may be repaired, but replacement is
generally preferable. Where damage is extensive,
replacement of the entire assembly is recommended.
18-54. FUSELAGE.
18-55. DESCRIPTION. The fuselage is of semi-
monocoque construction, conSisting of formed
bulkheads, longitudinal stringers, reinforcing chan-
nels, and skin panels.
18-56. NEGLIGIBLE DAMAGE. Refer to paragraph
18-13. Mild corrosion appearing upon alclad sur-
faces does not necessarily indicate incipient failure
of the base metal. However, corrosion of all types
must be carefully conSidered, and approved reme-
dial action taken. Small cans appear in the skin
structure of all metal aircraft. It is strongly rec-
ommended however, that wrinkles which appear to
have originated from other sources, or which do
not follow the general appearance of the remainder
of the skin panels, be thoroughly investigated.
Except in the landing gear bulkhead areas, wrinkles
occurring over stringers which disappear when the
rivet pattern is removed, may be considered neglig-
ible. However, the stringer rivet holes may not
align perfectly with the skin holes because of a per-
manent "set" in the stringer.
If
this is apparent.
replacement of the stringer will usually restore the
original strength characteristics of the area.
NOTE
Wrinkles occurring in the skin of the main
landing gear bulkhead areas must not be
considered negligible. The skin panel must
be opened sufficiently to permit a thorough
examination of the lower portion of the land-
ing gear bulkhead and its tie-in structure.
Wrinkles occurring in open areas which disappear
when the rivets at the edge of the sheet are removed,
or a wrinkle which is hand removable, may often be
repaired by the addition of a 1/2 x 1/2 x .060 inch
2024-T4 extruded angle, riveted over the wrinkle and
extended to within 1/16 to 1/8 inch of the nearest
structural members. Rivet pattern should be identi-
cal to existing manufactured seam at edge of sheet.
Negligible damage to stringers, formed skin flanges,
bulkhead channels, and like parts is similar to that
for the wing skin, given in paragraph 18-13.