Bell OH-58 C, Technical Manual

Page: 98 / 333

TM 55-1520-228-BD
AIRFRAME
Figure 4-17. Cutout in Damaged Skin
3. Cut a piece of substitute stringer
or stiffener to extend a minimum of six
fasteners beyond the damage on each end.
Use an angle, channel, or z-angle extru-
sion, if available, with a cross section
and strength equal to or larger than the
existing stiffener/stringer.
Sometimes
a single substitute stringer or stif-
fener can be extended to provide support
for several damages. This is better
than individual repairs, as it will
stiffen the airframe.
4. Remove rivets in the existing
stiffener/stringer and back drill rivet
holes in the substitute stiffener/
stringer to match existing holes.
Attempt to interpitch new fasteners
within the existing rivet pattern
if the area is inaccessible for
back-drilling.
5. Rivet the substitute stiffener/
stringer in place, Figure 4-18, using
the same size or larger rivets as those
removed.
NOTE
Stiffener can be placed on out-
side; however, this configuration
is nonpreferred.
7. Record BDAR action taken. When
mission is complete, as soon as
practical, repair the equipment/system
using standard maintenance procedures.
OPTION 2:
Tape Repair.
LIMITATIONS:
Repair may only be
used on secondary structure
moisture out.
No damage to
stiffener/stringer allowed.
PERSONNEL/TIME REQUIRED:
1 Soldier
30 Minutes
MATERIALS/TOOLS REQUIRED:
Army Green Tape (item 50,
or Aluminum Tape
to keep
App
X
C)
6. Rivet patch plate over hole using
same size as existing rivets.
4-54