TM 1-1520-265-23
g.
The Bondmaster is programmed to automatically set test parameters to a start-up or initial bond test. By
following the steps outlined above, adjustments to the FREQ, GAIN, and ALARM can help to refine the
selectivity in locating defects among differing bonded metallic and composite materials.
2.20.3.6 Inspection Procedure. Refer to Bond Testing Method, paragraph 1.4.6 and inspection areas shown in Figure 2-
20.
a.
Skin-to-Honeycomb Voids. Place probe on main rotor blade in location where test for skin-to-honeycomb bond
separation is desired and press NULL. Move probe from good to suspect area and note response. A strong
amplitude change and phase shift similar to the standard is indicative of a void. This set-up is very sensitive to
thin skin-to-core bonding. Move probe slowly over the skin and note the slight amplitude change (bounce) as the
probe senses alternately the honeycomb cell nodes and cell walls.
NOTE
The basic set-up provided above also selects a frequency that provide a satisfactory inspection
for voids associated with skin-to-spar, skin-to-trailing edge, doubler-to-doubler and doubler-
to-skin, and trim tab bonding.
b.
Use the NULL and GAIN adjustments to reset the ACTIVE screen for the areas to be inspected (do not go back
to SET mode). Also, compare similar areas. For example, to check for spar to skin voids, check front and back
of blade in the same area, or check another blade in the same area. Observe that, when moving the probe
chordwise from the spar to the trailing edge, the transitions at the spar-to-honeycomb and the honeycomb-to-
trailing edge strip are easily detected. When inspecting these areas, adjust the NULL and GAIN and move the
probe carefully along the transition using a straight edge or other guide. A localized phase and amplitude shift
similar to the test block indicates a void.
2.20.3.7 Marking and Recording of Inspection Results. Mark and record as required by paragraph 1.3.
NOTE
Attention shall be directed to accurately mark the boundaries of all voids. These markings will
be needed to determine acceptance or rejection criteria in accordance with applicable technical
manuals.
2.20.4 Backup Method. None required.
2.20.5 System Securing. None required.
2.21 MAIN ROTOR BLADE CUFF ASSEMBLY (ET).
2.21.1 Description (Figure 2-1. Index No. P1). The main rotor blade cuff assembly is bolted and bonded to the inboard
end of the main rotor blade. It provides a bolted attachment for the main rotor blade to the main rotor head spindle.
2.21.2 Defects. This inspection is used to verify crack indications found visually on the main rotor blade cuff assembly.
No cracks are allowed.
2-48
