Extra 200 - Page 126

CHAPTER 20
PAGE 9
EXT
RA - FLUGZEUGBAU GmbH
SERVICE MANUAL EXTRA 200
PAGE DATE: 1. July 1996
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:
ST
ANDARD PRACTICES AIRFRAME
Coin Tapping
Figure 1