Technical data

13773-001
61-10
Page 6 30 Nov 2000
(7) Approved Repairs - Blades (See Figure 61-103)
Nicks, gouges, and scratches on blade surfaces or on leading or trailing edges must be removed
prior to flight. Field repair of small nicks and scratches may be performed by qualified personnel
in accordance with FAA Advisory Circular 43.13-1(latest approved revision), as well as the main-
tenance practices specified below.
WARNING:
Re-work which involves cold working the metal, resulting in concealment of
damaged area, is NOT acceptable. Stress concentrations may exist which
can result in blade failure.
(a) Acquire necessary tools, equipment, and supplies.
(b) Repairs to blade are to be accomplished by removing material from the bottom of the
damaged area out to the damage perimeter in a smooth, flowing manner yielding a clean,
smooth depression which maintains the original airfoil’s general shape.
(c) Repairs that form a continuous line across the blade section (chordwise) are unaccept-
able.
(d) The area of repair is determined as follows:
Leading and trailing edge damage: Depth of nick x 10.
Face and camber: Depth of nick x 20.
Note: Leading edge includes the first 10 percent of chord from the leading edge.
The trailing edge consists of the last 20 percent of chord adjacent to the
trailing edge.
(e) After filing or sanding damaged area, polish with emery cloth, then with crocus cloth to
remove any traces of filing.
(f) Inspect repaired area with 10X magnifying glass and dye penetrant to ensure no indication
of file marks or course surface finish remain.
(g) Before returning to service, paint repaired area. (Refer to 61-10)
Description P/N or Spec. Supplier Purpose
File - Any Source Removal of dam-
age material.
Emery Cloth - Any Source Removal of dam-
age material
Crocus Cloth - Any Source Polishing of dam-
aged area.
Dye Penetrant - Any Source Inspection of dam-
aged area.
Magnifying Glass - Any Source Inspection of dam-
aged area.