B. Set reject, suppression or damping controls in "OFF" position.
C. Calibrate for fuse pin inspection locations (a) and (b) (see Figure 7).
(1) Calibrate instrument sweep time.
(a) Apply couplant and place transducer on one inch (2.54 cm) thick steel reference block.
(b) Adjust instrument controls to place initial pulse at zero and the first back reflection at 40
percent of screen width.
NOTE: Instrument sweep time calibration can be accomplished by placing transducer on
side of reference standard and setting second back reflection at 45 percent of
screen width (see Figure 3). The first back reflection from the one inch (2.54 cm)
block represents two inches (5.08 cm) of metal travel.
(2) Apply couplant to inspect reference standard as shown in Figure 3, Position 1A.
(3) Adjust oscilloscope controls to position the initial pulse signal at zero on horizontal baseline with
the two internal reflection signals identified by flagnotes 2 and 3 in Figure 4 at 60 percent and 50
percent time base, respectively.
(4) Manipulate transducer to obtain a maximum amplitude from the signal identified by flagnote 2.
Adjust the gain control so that the flagnote 2 signal amplitude is 80 percent of full screen height
(see Figure 4).
D. Calibrate for inspecting fuse pin locations (c) and (d) (see Figure 7).
(1) Calibrate instrument sweep time.
(a) Apply couplant and place transducer on reference standard at Position 1B (see Figure 3).
(b) Adjust instrument controls to obtain the initial pulse signal at zero on the horizontal baseline.
(c) Adjust the backwall signal from the bottom of the reference standard to 80 percent of the
horizontal baseline.
NOTE: Use an oily finger to damp reference standard backwall signal and confirm signal
location.
(2) Place transducer on reference standard at Position 3 (see Figure 3). Manipulate transducer to
obtain a maximum signal from notch (d) (see Figure 5). Signal will appear between 65 percent
and 70 percent of timebase.
(3) Adjust gain control to obtain a signal amplitude of 80 percent of full screen height from the (d)
reference notch (see Figure 5).
(4) Place transducer on Position 2 of reference standard (see Figure 3) and maximize signal from
notch (c) which should appear between 62 percent and 65 percent of timebase.
5. Inspection Procedure
A. Inspect fuse pin locations (a) and (b).
(1) Locate the inspection area (see Figure 7).
(2) Calibrate equipment for inspection of fuse pin locations (a) and (b) per Paragraph 4.C.
(3) Place transducer on inner edge of fuse pin head as shown in Figure 3, Position 1A. The
transducer should be close to, but not overlapping, the internal edge.
(4) Identify internal reflection signals per Figure 4, flagnotes 2 and 3 (Fuse pin P/N 69B89611 has a
different internal configuration which produces a different signal pattern; see Figure 6).
(5) Manipulate the probe radially to maximize internal reflection signals.
747
NONDESTRUCTIVE TEST MANUAL
PART 4 54-30-03
Page 2
Nov 15/2015D6-7170
ECCN 9E991 BOEING PROPRIETARY - Copyright © Unpublished Work - See title page for details
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