TM 1-1520-238-10
6-4
6.9 WEIGHT AND BALANCE CLEARANCE FORM F,
DD FORM 365-4.
Form F is the summary of the actual disposition of load in
the helicopter. It records the balance status of the helicop-
ter step-by-step. It serves as a work sheet on which to re-
cord weight and balance calculations and any corrections
that must be made to ensure that the helicopter will be
within weight and cg limits throughout the mission. There
are two versions of this form: Transport and Tactical. Each
was designed to provide for the respective loading ar-
rangement of these two types of aircraft. The general use
and fulfillment of either version is the same.
6.10 CENTER OF GRAVITY MANAGEMENT.
This paragraph contains fuel loading/management meth-
ods that can be used to maintain cg limits in flight and dur-
ing the expending of external stores for some helicopter
configurations. The table of expendables (table 6-1) pro-
vides a guide for quick definition of intermediate flight cg
as stores/fuel are expended at various gross weights and
at forward and aft cg limits. Table 6-1 eliminate calculation
of intermediate cg when the helicopter is well within limits.
When flight limits are doubtful or when operation is close
to cg limits, a detailed calculation must be made to deter-
mine any cg limit violation. When the storage bays are
used for miscellaneous equipment it is possible to cause
an aft cg condition.
6.10.1 Fuel Loading.
The helicopter takeoff cg can be
moved by loading either tank with more fuel than the oth-
er. Example: to move the cg forward, fill the forward tank
(1014 pounds of JP-4) and reduce fuel load in the aft tank
depending on cg shift required. For some missions, it may
be necessary to reduce the stowed weight.
6.10.2 Fuel Management.
The following example
presents normal cg/fuel management where each fuel
tank supplies an engine. This procedure prevents drastic
helicopter cg shifts as fuel is expended. Refer to Chapter
2 for fuel system details.
EXAMPLE:
1. Using table 6-1, refer to FUEL EXPENDED 500
lb EACH line. Note that fuel expended at 15,000
gross weight at forward cg limit produces a heli-
copter forward cg shift of –0.13 inch; and at aft
cg limits, +0.29 inch. When the helicopter cg is
at the combined fuel cg (202.8 inches) expend-
ing fuel will produce a zero shift. This is true only
when the forward tank fuel remains in the lower
portion of the L-shape tank. Refer to paragraph
6.12.
2. When filling the forward tank into the upper por-
tion of the L-shape, the combined fuel expended
cg moves aft to 212.4 inches which means that
the helicopter cg will always shift forward during
fuel burnoff in this area.
3. Refer to the 1000 lb fuel expended each tank
line in table 6-1. Note that fuel expended at
15,000 gross weight at aft cg limit is +0.41 inch-
es. This is correct when the total 2,000 pounds
of fuel is expended, but this includes a helicopter
cg shift forward during initial fuel burn-off due to
the forward L-shaped tank.
4. For the full fuel example based on a conserva-
tive gross weight of 15,000 pounds and cg of
201.0 inches, 208 pounds of aft fuel must be
transferred so that all fuel can be expended
equally. A helicopter cg shift of – 1.49 to – 1.68
inches is produced depending on when the
transfer occurs. When working with full fuel, it is
advisable to calculate several intermediate
points and determine when it’s best to transfer
fuel.
