And Core - Bell OH-58A Technical Manual

Remove existing rivets where the
3.
repair parts will overlap existing
rivets if the area is accessible for
back-drilling holes. If not, install
rivets between existing rivets if space
permits.
4. Rivet the repair parts in place
using original diameter rivets or larger
if necessary.
Record BDAR action taken. When
5.
mission is complete, as soon as
practical, repair the equipment/system
using standard maintenance procedures.
4-20. HONEYCOMB CORE FLOOR OR PANEL
DAMAGE.
GENERAL INFORMATION:
a. Part of the bottom shell, top
deck, shelves, interior panels, and the
fin panels are honeycomb core struc-
tures.
b. Various repair options are given
for a range of damage size.
Small Damage to One Skin and
OPTION 1:
Core or Both Skins and Core - Less Than
2 Inches Maximum Diameter.
Procedure is designed only
LIMITATIONS:
to keep moisture out. No additional
strength has been added.
PERSONNEL/TIME REQUIRED:
. 1 Soldier
. 15 Minutes
MATERIALS/TOOLS REQUIRED:
. Army Green Tape (item 47, Appx C)
or Aluminized Tape
PROCEDURAL STEPS:
Remove ragged edges, Figure 4-23.
1.
Apply tape over repair to keep out
2.
moisture.
3. Record BDAR action taken. When
mission is complete, as soon as
practical, repair the equipment/system
using standard maintenance procedures.
OPTION 2: 2 to 8 Inch Damage, One Skin

and Core.

LIMITATIONS: None.
PERSONNEL/TIME REQUIRED:
. 1 Soldier
90 Minutes
MATERIALS/TOOLS REQUIRED:
Metal Set or Equivalent Filler
Compound (item 2, Appx C)
Patch Plate
Cherry Rivets (item 38, Appx C)
. Solvent Cleaner; Naptha (item 5,
Appx C) or Equivalent
PROCEDURAL STEPS:
Remove damaged skin and core, Figure
1.
4-24. Clean surface 6 inches around
holes with cleaner. The maximum damaged
area that may be cut out is 8 inches.
2. Make a patch plate as shown in Figure
4-25. Make plate 2 inches larger than
cutout. Lay out and drill rivet pattern.
3. Completely fill void with metal set
Add slight excess to
fill compound.
allow for shrinkage.
Apply metal set to area between the
4.
patch plate and panel. Assemble to
panel with 1/8 blind rivets.
5. Record BDAR action taken. When
mission is complete, as soon as
practical, repair the equipment/system
using standard maintenance procedures.
Damage to Both Skins and
OPTION 3:
Core, 2-8 Inch, Only One Side of Panel
is Accessible.
LIMITATIONS: None.
TM 55-1520-228-BD
AIRFRAME
4-63