3. Prepare for the Inspection
A. Identify the inspection locations. See Figure 1.
B. Get access to the inspection surfaces of the fuse pin.
C. Remove all paint and sealant from the area of the fuse pin that the transducer will touch and clean fully.
Use a non-abrasive scraper to remove the paint. The part number is etched on the end of the fuse pin
and can cause the surface to be rough. If necessary, lightly sand this area by approved methods to
permit the transducer to fully touch the part.
NOTE: Make sure that the part number is not removed when you sand the fuse pin.
4. Instrument Calibration
NOTE: Because of the small transducer size, a transducer guide is used during the inspection.
A. Connect the transducer to the instrument and do the initial adjustments of the instrument.
NOTE: Do not use reject unless the instrument has certified linear reject. Do not use more than 10%
reject.
B. Set the instrument frequency to 10 Mhz. See Paragraph 2.A.(1).
C. Find the part number on the fuse pin to be examined or refer to Table 1.
D. See Table 1 for the transducer guide position to use.
E. Install the transducer in the transducer guide. Make sure the transducer fully touches the surface of the
reference standard. See Figure 4.
F. Put couplant at position 1 on the reference standard. Put the transducer at this position. See Figure 4.
G. Adjust the instrument controls to get the first back surface signal at 50% of full screen width and the
second back surface signal at 100% of full screen width. The instrument is now calibrated for a 5.0 inch
(127 mm) instrument screen range. See Figure 4.
H. Put couplant on the reference standard at position X shown in Figure 5. Put the transducer at this
position. The back surface signal must occur near 82% of full screen width.
NOTE: Signals can occur between 18% and 35% of full screen width that are caused by internal
reflections at the near end bottleneck on some fuse pins (see Figure 5, Detail I).
I. Move the transducer guide above reference notch 1 at position Y (see Figure 5). The screen location
for the reference notch 1 signal must be at 55% of full screen width, as shown in Figure 5.
J. Move the transducer guide above reference notch 2 at position Z (see Figure 5). The screen location
for the reference notch 2 signal must be at 65% of full screen width as shown in Figure 5.
K. Turn the transducer in the transducer guide hole to make sure the notch signal is at a maximum
amplitude. Move the transducer guide above reference notch 2, position Z one more time to make sure
the signal is at a maximum height. Adjust the instrument gain controls to get the notch 2 signal at 80%
of full screen height. See Figure 5.
L. Examine all noise signals to make sure the signal-to-noise ratio is larger than 3:1. If the signal-to-noise
ratio is less than 3:1, try a different transducer or a higher frequency transducer.
NOTE: Make sure the initial pulse is not more than 20% of full screen width. If necessary, adjust the
instrument controls or use a different transducer.
M. Put couplant on the fuse pin to be examined. Then put the transducer guide with the transducer on the
end of the fuse pin.
747
NONDESTRUCTIVE TEST MANUAL
PART 4 54-30-07
Page 2
Nov 15/2015D6-7170
ECCN 9E991 BOEING PROPRIETARY - Copyright © Unpublished Work - See title page for details
EFFECTIVITY
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