MD Helicopters CSP-900RMM-2, Servicing And Maintenance

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CSP − 900RMM − 2 MD Helicopters, Inc.
Rotorcraft Maintenance Manual
Page 6
Revision 25
53-20-00
9G53-029A
TUB SHELL
CABIN SILL
(LH AND RH TYPICAL)
LH KEEL BEAM
ASSEMBLY
RH KEEL BEAM
ASSEMBLY
FUEL CELL LINER
ATTACHMENT ANGLE
(LH AND RH TYPICAL)
FUEL CELL
SUPPORT RIBS
COCKPIT SILL
(LH AND RH TYPICAL)
TUB SHELL
LONGERONS
LOWER DOOR TRACK POCKET
Figure 3. Tub Shell Assembly
Keel Beams −
The left and right keel beams
are primary structural components and are
the longitudinal and vertical load bearing
structural components of the lower section of
the fuselage. In addition, the keel beams form
the side walls of the fuel cell cavity and
support the loads produced by the fuel in the
fuel cell. The keel beams are symmetrically
located within the tub shell assembly, at LBL
and RBL 24.00.
Early Configuration −
keel beams are second­
arily bonded to the interior skin of the tub
shell and riveted to the boat tail tub.
Current Configuration −
keel beams are
riveted to the tub shell and the boat tail tub.
The keel beams are composite sandwich
panels. The panels utilizes multiple ply
graphite/epoxy and aramid/epoxy skins
cocured with Nomex honeycomb cores. In
areas in which secondary attachment of
additional components occurs, the honeycomb
core is tapered and additional reinforcement
plies of graphite/epoxy are inlaid. In areas in
which secondary attachment of metallic
components occurs, a barrier ply of fiberglass/
epoxy is cocured to the surface of the respec­
tive skin. The keel beam panels are fabricated
with integral upper and lower flanges. The
lower flanges are utilized for attachment of the
keel beams to the tub shell and boat tail
assembly. The upper flanges provide the
provisions for attachment of the cabin and
baggage compartment floor panels.