Table 2-2. Propeller Defects - CONT
Damage caused when two parts are improperly matched.
A sharp sided gouge or depression with a V-shaped bottom which is generally
the result of careless handling of tools and parts.
A damaged hole which does not have the same concentric center.
A buildup or rolling of metal from one area to another, which is usually caused
by insufficient lubrication, clearances, or foreign matter.
Small, irregularly shaped cavities from which material has been removed by
corrosion. Corrosion can be caused by oxidation (rust), acid attack (etching,
perspiration), electrolytic attack (non-distilled water). The bottom surfaces of the
cavities are usually dark.
A series of deep scratches caused by foreign particles between moving parts, or
careless assembly or disassembly techniques.
Shallow, thin lines or marks, varying in degree of depth and width, caused by
presence of fine foreign particles during operation or contact with other parts
Damage caused when a part is stressed in two different directions.
The breakdown of a functional/active surface due to fatigue, usually in the form
of irregularly shaped pits. The edges of the pits have indications of cracking and
Damaged or unusable threads of a bolt or screw.
Breakdown of surface material caused by corrosion.
Acid or caustic materials should not be
used. Power buffers, steel wool, steel
brushes, or any other tool or substance that
may scratch or mar the blade should be
b. Propeller Cleaning. Propeller blades and hubs
Specification P-D-680 and in accordance with the
applicable maintenance manual.
If a high polish is desired, a number of good
grades of commercial metal polish are
available. After completing the polishing
operation, all traces of polish should be
immediately removed. When the blades are
clean, they should be coated with a clean film
of engine oil or suitable equivalent.
c. Propeller Inspection. Inspect propellers regularly
in accordance with the applicable maintenance manual.
The following paragraphs explain general inspection