JUL 2020 Chapter 5 Inspections Page 5.5
5-34 Elastomeric Bearings
Refer to Figure 5-3. Elastomeric bearings are used in the G062-1 tail rotor hub assembly.
Fatigue, oil contamination, or overload can degrade the elastomer.
Small surface cracks (fatigue cracks) and elastomer dust or “eraser crumbs” are normal
and are not cause for replacement. As cracks grow, enough elastomer will be lost to
cause reduced stiffness and increased vibration. Replace bearing if crack is deeper than
0.10 inch or cracks are present over more than 25% of elastomer face.
Avoid elastomer exposure to oil, grease, hydraulic fluid, cleaning solvent, and rust-
preventative fluids. Immediately wash off contaminants with detergent and water.
Replace a contaminated bearing that exhibits swelling, wavy edges, or debonding.
Overload occurs when elastomer’s tensile strength or rubber-to-metal bond strength is
exceeded. This can occur when normal loads are applied to a bearing weakened by
fatigue or oil contamination. Overload is indicated by large clean cracks or extrusions
from elastomer.
Elastomer may also separate (debond) from metal bushings. Replace bearing if separation
exceeds 25% of bonded area.
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