CHAPTER 20
PAGE 9
PAGE DATE: 7. July 2010
MAINTENANCE MANUAL EXTRA 300LT
20-10-05 Measuring Techniques
When using stop nuts, the safety torque (friction torque or
braking torque) should be added to the table standard values.
This value is indicated on the dial of the torquemeter, before
the nut contacts the attachment surface.
Always torque nuts for fastening, if possible. When bolts are
torqued there might be an additional torque value due to shaft
friction. This torque can be determined by a torquemeter
before the bolt head contacts the attachment surface and
should be added to the table value.
20-10-06 Coin Tapping
Inspection for damage is more critical for composite struc-
ture than for conventional structures. A large washer or
similar object is a valuable tool for detecting debonds in the
airframe surface. When a large washer is lightly bounced
against a solid structure, a clear metallic ring should be
heard. If delamination is present, a dull thud will be heard.
This procedure is shown in the following Figure 1:
Figure 1 Coin Tapping