TM 55-2840-241-23
possible to fully describe all of the damage
conditions that could be incurred; therefore, if
possible to fully describe all of the damage
conditions that could be incurred; therefore, if
damage is within rework limits, but there is
reasonable doubt about the strength of the re-
worked blade as compared to a new blade, re-
place the engine. Light polishing to remove
minor nicks, where blade dimensions are basi-
cally unchanged, is permissible on the other
2/3 of the blade.
Blend and polish blades or vanes in a longitudi-
nal direction only with the rework forming a
smooth blend with the basic airfoil. The num-
ber of blades or vanes which maybe reworked
is not limited. Other than restriction to the out-
er 2/3 of the blade, the limiting factor of blade
or vane rework is engine performance. Any re-
duction of blade or vane area will decrease the
a. Inspect for cracked or missing compressor blades
- none are permitted. If crack in compressor blade is
b. Inspect the compressor rotor blades and wheel
hubs for evidence of corrosion. Corrosion must be re-
moved by lending and polishing. (Refer to paragraph
7-24.) Replace the engine if pitting in any area of the
blade forjs a definite line, pitting exceeds the blend lim-
its, or if pitting in the inner 1/3 of blade.
c. Inspect the compressor rotor blades and wheel hubs
for nicks, dents and scratches in areas other than the
blade leading and trailing edges. All damage and
imperfections must be blended out. (Refer to paragraph
7-24 c and d.) Blended areas must not exceed the limits
shown on figure 7-12.
Change 23
7-4.1 /(7-4.2 blank)
efficiency of the compressor and the perfor-
mance of the engine. Remove as little material
as possible. No sharp edges, burrs, cracks or
tears are acceptable.
suspected, refer to TM 1-1520-254-23, Technical Manual
Aviation Unit Maintenance (AVUM) and Aviation Inter-
mediate Maintenance (AVIM) Manual Nondestructive
Inspection Procedure for OH-58 Helicopter Series.
