TECHNICAL MANUAL MAINTENANCE MANUAL FOR ARMY CH-47D HELICOPTER (1992)

TM 55-1520-240-10

SECTION II WEIGHT AND BALANCE

6-4. DD Form 365-3 Chart C - Basic Weight and

insure that the helicopter will be within weight and C.G.

Balance Record.

limits. Sufficient completed FORMS F must be onboard

the helicopter to verify that the weight and C.G. will

Chart C is a continuous history of the basic weight and

remain within allowable limits for the entire flight.

moment resulting from structural and equipment

Sufficient forms can be one (for a specific flight) or it

changes in service. At all times, the last weight and

moment/1,000 are considered the current weight and

can be several. Several FORMS F for various loadings

balance status of the basic helicopter.

of crew, passengers, stores, cargo, fuel slingloads, etc.,

which result in extreme forward and extreme aft C.G.

6-5. DD Form 365-4 (Weight and Balance Clear-

locations and variations in gross weight, but which

ante Form F).

remain within limits. There are two versions of this

form: Transport and Tactical; they are designed to

This form is used to derive the gross weight and

provide for the respective loading arrangements of

center-of-gravity (C. G.) of the helicopter. The FORM F

furnishes a record of the helicopter weight and balance

these two type aircraft. The general use and fulfillment

status at each step of the loading process. It serves as a

of either version are the same. Specific instructions for

worksheet on which to record weight and balance

filling out the form are given in TM 55-1500-342-23.

calculations and any corrections that must be made to

6-3

55-1520-240-10

SECTION III FUEL/OIL

6-6.

Fuel and Oil Data.

The following information is provided to

range of fuel specific weights to be exp

The CH-47D is equipped with six fuel tanks and an integral

of fuel will vary depending on fuel te

oil tank on each engine. The capacities of each fuel tank and

weight will decrease as fuel temperature

each engine oil tank are given in chapter 2.

fuel temperature decreases at the rate of

6-7.

Fuel Weight and Moment.

gal for each

15°C change. Specific weig

between lots of the same type fuel at th

Fuel moments for the forward auxilas much asa0.5 lb/gal.l-

The following

iary fuel tanks are shown in Figuspecific weights at 15°Cor

may be used for

these tanks are constant thus, for a given weight of fuel there

ning.

is no variation in fuel moment with change in fuel specific

weight. The common auxiliary fuel tank Fuel Type4.

Specific Weight

The full tank usable fuel weight will vary depending upon

fuel specific weight. The gallon scales oJP-4gure 6-26.5 lb/gal

on JP-4@ 6.5 lb/gal, JP-5@ 6.8 lb/gal, anJP-5-8 @ 6.76.8 lb/gal

The aircraft fuel gage system was designeJP-8r use wi6.7 lb/gal

but does tend to compensate for other fuels and provide

6-8. Oil Data.

acceptable readings. When possible the weight of fuel

onboard should be determined by diFor weight and balance purposes, the wei

craft fuel gages.

included in the basic weight.

6-4

Change

TM 55-1520-240-10

SECTION IV

PERSONNEL

6-9. Personnel Loading and Unloading.

back rest tension. Seat tension is adjusted by relocating

retaining pins in the holes drilled in the front seat tubes.

The loading procedures should be accomplished and

A row of male snap fastener studs along the rear of the

observed before loading to ensure the safety and com-

seat-back rest matches a row of female snap fastener

fort

of personnel to be airlifted:

sockets along the rear edge of the seat fabric. These

Passenger compartment - Clean.

fasteners are jointed to provide greater seat depth for

troops equipped with parachutes. Two stowage straps

Equipment

- Stow and secure.

are attached to the underside of the seat fabric; one is

Troop seats

- Install, as required.

equipped with a hanger clip for folded stowage, the

other is equipped with a buckle for rolled stowage. The

Litters - Install, as required.

seats will normally be stowed in the folded position for

Static line anchor cable

- Install, as required

cargo transport.

Safety belts - Check, attached.

A 2,000 -pound-capacity nylon web safety belt is pro-

Emergency equipment - Check.

vided for each seat occupant. The belt is adjustable and

is equipped with a positive-grip buckle fastener de-

Emergency exits - Inspect.

signed for quick release.

i. Special equipment - Check.

6-13. Troop Seat Installation. Install the troop seats

6-10. Personnel Weight Computation. When the

from the rolled position as shown in figure 6-6. Install

helicopter is to be operated at critical gross weights, the

troop seats from the folded position by performing steps

exact weight of each individual occupant plus equip-

1, 4, 6, and 7 of figure 6-6.

ment should be used. If weighing facilities are not

available, or if the tactical situation dictates otherwise,

6-14. Troop Seat Stowage. Stow the troop seats in

loads shall be computed as follows:

the rolled position by performing steps 1 through 9 in

reverse order as set forth in figure 6-6. Stow troop seats

a. Combat equipped soldiers - 240 pounds per indi-

in the folded position by reversing the procedures in

vidual.

steps 7, 6, 4, and 1 of figure 6-6.

b. Combat equipped paratroopers - 260 pounds per

individual.

6-15. Troop Loading. The loading and unloading of

troops will normally be accomplished through the low-

c. Litter patient (including litter, splints, etc.) - 200

ered aft cargo door and ramp. The most orderly and

pounds per individual.

efficient troop loading procedure is for the troops to

d. Medical attendants -

200 pounds per individual.

occupy seats from the front to the rear. In unloading,

the troops will leave the helicopter progressively from

e. Crew and passengers with no equipment - Com-

the rear to the front. If the troops to be loaded are

pute weight according to each individual’s estimate.

carrying full field equipment, it is recommended that

f. Refer to figure 6-3 or 6-4 for personnel or litter

the seat-back rests be folded to avoid entanglement with

patient moment data. The chart (fig. 6-3) provides

the equipment and damage to the seat back rests.

precomputed moments for each troop seat position.

6-16. Troop Commander’s Jump Seat.

6-11. Seating Arrangement.

A collapsible fold-away seat is located in the cockpit

Seating arrangement for 33 fully equipped ground troops

entrance for the use of the troop commander. The seat

is provided by ten 3-man seats and three 1-man seats

is made of nylon on a tubular aluminum frame.

(fig. 6-5). A row of five 3-man seats is installed along

each side of the cargo compartment. One-man seats are

6-17. Litter Arrangement.

installed at the forward and aft ends of the left-hand

There are provisions for 24 litters, three tiers, four high,

row of seats and one at the aft end of the right-hand row

along each cargo compartment wall normally occupied

of seats.

by the troop seats (fig. 6-5). The two l-man seats in the

6-12. Troop Seats.

aft section of the cargo compartment may remain in

place to serve as seats for medical attendants. If needed,

These seats are made of nylon on tubular aluminum

the l-man seat in the forward section of the cargo

frames and are joined together for greater rigidity and

compartment may also remain. It is not necessary to

comfort. The seats are joined by means of slide bolt

remove the troop seats to install the litters.

fasteners in the front seat tubes, zipper fasteners on the

underside of the seat fabric, and snap fasteners along

6-18. Litter Support Brackets. Refer to figure 6-7

the vertical edges of the seat-back rests. A slide adjuster

for litter installation. Four litter support brackets are

below the back rest hanger clips affords adjustment of

permanently attached to each litter pole and each litter

6-6

TM 55-1520-240-10

strap. The brackets are spaced

t18 inches apart.eAfloor. The st

locking device in each bracket soverhead recesses directly over t

in place. The locking device conthe straps will be attached. The

slotted locking bar, and a lock covered with canvas flaps which a

handle is hinged to the lower jsides.the bracket. The

slotted locking bar is hinged, cam fashion, to the locking

handle. The handle clip is hinged6-20.LitterhLoading.pperThe loading

of litte

bracket and has a hook end whichaccomplished throughf

the lowered

the slots in the locking bar. Whramp. The forward litter

tiers sh

moved down, it forces the lockinto bottom, and then progressively

tension on the handle clip. Whentients requiring in-flight medica

moved up, it pulls the locking btioned to enable access to injuri

handle clip to a positive grip othe helicopter is to

be loaded w

troops and litter patients, the

6-19. Litter Poles and Straps.

Twelve litterpositioned to the rear of the tr

are provided for use in adapting the helicopter for

medical evacuation. An attachment6-21.CombinationSeatoandLitterArrangement.m

of each pole has two indentations, on opposing sides,

which fit between two studs locaCombined troop and litter patient

The upper rear side of the poleported by arranging seats and lit

ives the various combination

slots by which the pole is anc6-1 g

seatback support tubes. A metal which can be used.nside

the pole locks under one of the studs when the pole is

installed. This prevents accide6-22.StaticdLine AnchoraCable.on of the

pole. The retainer is released for litter pole removal by

A static line anchor cable is pr

pulling the grommet which protrudes from the front of

normally stowed in a container (fi

the pole. When not in use, the litter poles may be

right side of the cargo compartm

stowed at station

120.

When the static line anchor is i

Twelve litter straps are used wattached to the structure between

support the litters. The straps A static line retriever is provi

or downward by slide adjustersanchor cable. The retriever is us

lower ends of the straps. All ofthe winch and is provided

to haul

the top with slipover hooks whthe end of the jumping exercise o

brackets in the strap stowage reparatrooper in an emergency. Refer

each strap has a fitting for aprocedures on using the static li

Table

6Seat and Lifter Arrangement Data

PERSONNEL

LITTER TIERS

SEATS

LITTERS

(4-MAN)

(1-MAN)

(3-MAN)

6-15

TM 55-1520-240-10

SECTION VI

CARGO LOADING

6-24. General.

accessible through the utility hatch door. The lower

rescue door is secured by four latches centered around

This section contains information and instructions for

the door perimeter. These latches are connected by

loading and securing cargo in the helicopter. It lists and

linkage to an actuator labeled OPEN and CLOSED. A

describes the items of equipment incidental to these

handcrank, stowed in spring metal clips on the left side

operations, instructions for their use, and illustrations

of the fuselage, is used to unlatch the door and turn the

where necessary or desirable. It is not the intent of this

gears. A drive shaft, which is turned by the gears, moves

section to teach principles of cargo loading. It is the

the door actuator links. The door opens downward and

purpose of this section to provide detailed information

aft underneath the fuselage where it remains during

on cargo loading with regard to this helicopter.

operation.

6-25. Cargo Compartment.

The cargo compartment (fig. 6-9) is 366 inches long, 90

Although tightening of the tiedown straps

inches wide, and 78 inches high. These dimensions are

may be necessary to reduce internal load

uniform throughout the cargo compartment, unless the

vibrations, excessive tightening of tiedowns

aircraft is configured with HICHS (fig. 6-9). The lower

attached to the outboard row of tiedown

rescue door is opened for rescue operations, aerial

fittings will limit the effectiveness of the

loading, and external cargo transport operations. A

isolated cargo floor.

hydraulically operated door and ramp provide a means

for quick and efficient straight-in loading and unload-

ing.

6-29. Cargo Compartment Floor. The floor is made

of extruded panels, riveted together in sections. Raised

NOTE

extruded ridges, running the entire length of the floor,

Figure 6-10 shows the maximum cube size

provided surfaces on which cargo is moved. The flooring

which can be taken into the helicopter

in the cargo compartment contains sections on either

through either the main cabin entrance, util-

side of the centerline which are strengthened to serve as

ity hatch, or cargo loading ramp.

vehicle treadways. The flooring, from station 200 to 400

and from buttline 44 left to 44 right, rests on rubber

vibration isolators which reduce overall internal load

6-26. Main Cabin Entrance. The main entrance door

vibrations. Tiedown fittings (fig. 6-11) for securing cargo

is located on the right side of the cargo compartment at

are installed in the floor. There are also studs for

the forward end and measures 66 inches in height by 36

attaching troop seats, litter supports, and the base plate

inches in width. The door is composed of two sections:

for the maintenance crane. The flooring is covered with

the upper section rolls inward and upward to a rest

a walkway compound which provides a non-skid surface

position overhead; the lower section opens outward and

for personnel and for vehicles. In construction, the ramp

downward and serves as a step in the lowered position.

floor is identical with the cargo floor.

NOTE

6-27. Utility Hatch Door. The utility hatch door is in

the center of the cargo compartment floor between

Whenever possible, place all wheeled vehi-

stations 320 and 360. The door is hinged along its entire

cles entirely on the treadways between sta-

forward edge. It opens upward and forward to expose

tions 200 and 400.

the lower rescue door and the cargo hook. The door is

unlatched by pressing the knob labeled PUSH, and is

latched by pressing the unmarked knob.

6-30. Strength Areas. The weight which the cargo

compartment floor (fig. 6-12) can support varies. These

variations are largely due to differences in strength of

NOTE

supporting frames and fuselage construction, not be-

When opening or closing the lower rescue

cause of varying floor strength. To gain the maximum

door, be certain that the cargo hook is

benefit from the cargo compartment floor, the following

properly stowed and supported by the re-

definitions and weight limitations must be observed.

straining straps. In addition, close the rescue

door, using the actuator only to the point

6-31. Uniformly Distributed Loads. Uniformly dis-

where the latch can engage; the latches will

tributed loads are those loads wherein the total weight

then lift the door and compress the door

of the item is equally spread over the item’s entire

seal.

contact area. Contact area is large compared to size and

weight of the load.

6-28. Lower Rescue Door. When closed, the lower

6-32. Uniformly Distributed Load Limits. Compart-

rescue door forms a part of the fuselage bottom. It is

ments C, D, and E (fig. 6-12) are limited to

300 psf. The

6-18

Change 3

TM 55-1520-240-10

Figure 6-10. Maximum Package Size (Sheet 1 of 3)

cargo loading ramp (fig. 6-12) is limited to

300 psf with

6-35. Load Limits.

a maximum total load of

3,000 pounds when the ramp is

Vehicles exceeding the limitations may be loaded with

level with the cargo floor.

the use of shoring, provided that the vehicle weights

remain within the operating weight limits of the heli-

6-33. Concentrated Loads. Concentrated loads are

copter. In cases where the wheels of a vehicle cannot

those loads wherein the total weight of the item is

rest on both treadways because of a narrow wheel tread,

supported by a contact area that is small compared to

shoring must be used to spread the load over the

the size and weight of the load.

treadways. General cargo must not exceed floor pres-

sure of 300 psf. An easy way to determine floor pressure

6-34. Concentrated Load Limits. Concentrated

of various loads is to divide the weight of the load by the

loads can be loaded on the treadways and on the

contact area (in square inches or square feet).

walkway. The treadways aft of station 160 and ramp

extensions are stressed for a total wheel load of

2,500

NOTE

pounds. The treadways forward of station 160 and the

Load on pallets supported by the longitudi-

walkway can be loaded to a total wheel load of

1,000

nal beams or skids resting on the floor can

pounds. Concentrated loads are not to exceed

75 psi for

result in concentrated loads at points where

pneumatic tires or

50 psi for block or roller-type wheels.

the beam/skid rests on or crosses floor form-

ers. The concentrated load can be deter-

NOTE

mined by dividing the weight of the item by

the number of floor former/skid intersection

The above floor loading limitations apply to

points or by the number of locations where

the static weight of the item prior to applying

the skid rests on the floor formers. The floor

any restraint devices.

limits are the same as the concentrated load

limits in the treadway and center section of

the floor, that is 2,500 pounds and

1,000

NOTE

pounds.

The minimum distance, in feet, between the

centers of any two adjacent concentrated

6-36. Compartment Identification.

loads is determined by totaling the adjacent

loads and dividing by 1,000.

The cargo compartment is divided, for weight and

balance purposes, into three compartments designated

6-20

TM 55-1520-240-10

Figure 6-10. Maximum Package Size (Sheet 2 of 3)

C, D, and E, running fore and aft. (fig. 6-1). When the

in the ramp are in a rectangular pattern. Each 5,000-

cargo ramp is used as an extension of the cargo com-

pound-capacity fitting swivels freely and is capable of

partment, it is designated as F for weight and balance

resisting a single maximum load of 5,000 pounds exerted

purposes. These compartment designations and their

along any radius of a hemisphere, the flat side of which

limiting fuselage stations are stenciled on the cargo

is the surface of the floor. The fittings are hinged so that

compartment walls.

they can be seated in floor recesses when not in use.

6-37. Compartment Capacities.

Based on a maximum distributed floor loading of

300

psf, the compartment capacities can be obtained by

The 10,000-pound-capacity tiedown fittings

multiplying the floor loading by the floor area of the

must be screwed into the threaded recepta-

individual compartment; however, this weight may ex-

cles to full depth to achieve their rated

ceed present limitations. Figure 6-12 lists the maximum

capacity.

capacity of each compartment. In addition to the limi-

tations in figure 6-12, compartment loads will be limited

by those limitations set forth in Chapter

6-40. Ten Thousand-Pound-Capacity Tiedown Fit-

tings. There are eight 10,000-pound-capacity tiedown

6-38. Tiedown Fittings.

fittings on the cargo compartment floor. Four fittings

are interposed along both outboard rows of 5,000-

Tiedown fittings (fig. 6-11) for securing cargo are in-

pound-capacity fittings, spaced at intervals of 80 inches

stalled on the cargo compartment floor and on the ramp

from station 240 to station 480. These fittings are not

floor. All the fittings are D-ring types. There are

always used and they might be in the way when installed

5,000-pound-capacity tiedown rings (83 in the fuselage

Therefore install only when necessary. When they are to

floor and 4 in the ramp floor) and eight 10,000-pound-

be used, the fittings are screwed into threaded recepta-

capacity tiedown fittings. The fittings are normally used

cles at the fitting locations. When the fittings are not

with tiedown devices which will not exceed the limits of

being used, threaded plugs are screwed into the recep-

the fitting.

tacles to protect the thread in the receptacles.

6-39. Five Thousand-Pound-Capacity Tiedown

6-41. Cargo Loading Aids.

Fittings. The 83 5,000-pound-capacity tiedown fittings

in the cargo compartment floor are equally spaced in

The helicopter has a number of features to facilitate

five rows spaced 20 inches apart longitudinally. The four

loading of cargo. Some of these features are parts of

6-21

TM 55-1520-240-10

Figure 6-10. Maximum Package Size (Sheet 3 of 3)

systems and are permanently installed; others are equip-

this situation, the weight of the cargo item resting on the

ment which is stowed in the helicopter. The following

ramp must not exceed

3,000 pounds or

300 psf.

paragraphs contain descriptions of items classed as

6-43. Auxiliary Loading Ramps.

loading aids. Specific instructions for some of these

items may be found in other parts of this manual and

Three auxiliary loading ramps are hinged to the aft end

are referenced.

of the ramp (fig. 6-15). When the lamp is lowered, these

auxiliary ramps are unfolded to provide flush contact

between the ramp and the ground. The auxiliary loading

6-42. Cargo Loading Ramp.

ramps can be positioned to accommodate various vehi-

The ramp provides a means of quickly loading and

cle tread widths or butted together to facilitate winching

unloading troops and cargo. It can also be used to

of bulk cargo. When not in use, the auxiliary ramps are

support portions of a cargo load which exceeds the

stowed in an inverted position on the floor of the ramp

longitudinal dimensions of the cargo floor. When used

or removed. One of the auxiliary loading ramps when

for additional cargo space, the ramp must be positioned

attached to the ramp can also be used as a work

so that the ramp floor is level with the cargo floor. In

platform. A collapsible support attached to the ramp

6-22

TM 55-1520-240-10

bottom allows the ramp to be posilowered to ground rest,

the ramp i

height when used as a work platfoproximately

6.75° and maintains a

head clearance, (if HICHS is not i

6-44. Winch.

compartment. A continuous hinge run

the aft upper edge of the ramp and

Refer to Chapter 4, Section III.

loading ramps. The auxiliary ramps

between the ramp and the ground fo

6-45. Cargo Door and Ramp.

unloading. They can be adjusted la

The cargo door and ramp has an uvarious vehicle tread widths. Hydra

door, and a lower section, or rampramp is supplied through the utilit

ramp when the ramp is being lowered and extends when the

and rai

ramp is being raised. Retraction o6-46.RAMPtCONTROLiValve. of theLowering

be isolated through the ramp sequthe ramp is controlledpby a RAMP CO

can be raised or lowered with thright side of the aft cargo compar

ramp or extended. The door is anand the overhead at sta

490 (fig

and only provides closure; therefCONTROL valve is operatedhe

either el

ramp will be understood to includElectrical operationeiseperformed

movements. The cargo door is jetPWR Switch to EMERG, a

nd using th

emergency exit. The cargo door and ramp is located at the

control switch on the cockpit overh

aft end of the cargo compartment and is used for troop and

(Chapter 2, Section VI). Manual ope

cargo loading and unloading. In closed position, it conforms

by setting the RAMP PWR switch to

to the side contours of the fuselage (fig. 6-15). Internal locks

in the ramp actuating cylinders pthree-positiontleveremounted on th

and constitute the only locking mvalve. The lever positions are lab

ramp closed. The ramp is hinged t(down). The control lever can be re

rearward and downward to rest ot

rough a hinged panel on the aft

Figure

6Cargo Door and Ramp

Change

6-29

TM 55-1520-240-10

CAUTION

f. 10,000 lb tiedown fittings -

g. LoadingCheck,

for condition an

Do not press the sequence valve plunger

unless the ramp is down.

h. Weight and balance data

- Chec

i. Emergency equipment

- Check.

6-47. Ramp Control Sequence Valve.

A mechani-

cally operated sequence valve conj. Emergency exits ofInspect.

cargo door and ramp operation (fig.

6-17). The valve is

k. Cargo load

- Inspect.

below the ramp control valve at the

ramp hinge line. A

plunger on top of the valve is manually pressed to hold the

cargo door at full open during ra6-51.RampOperation.on. The plunger

can be locked in the depressed position by rotating a retainer

pin which extends from the side o6-52.tNormalOperation..

6-46. Pressure Actuated Valve.

Ramp operation is

stopped during cargo door operation by a hydraWARNINGc pressure

actuated valve. The valve is located near the ramp control

valve (fig. 6-16). A plunger providesWhenmthenRAMPPWR switch is OFF, be

valve if it sticks.

sure the RAMP CONTROL VALVE remains

at STOP. If the RAMPCONTROL VALVE is

6-49. Accumulator Gage.

A gage at station

53moved to UP or DN,

the ramp may free fall.

side, indicates APU accumulator pressure in psi (fig. 6-16).

A pressure reading on the accumulator gage in excess of

2,500

psi is sufficient for operating t1. Lower the ramp as follows:

a. RAMP PWR switch

- ON.

6-50. Equipment Loading and Unloading.

The following procedures should be observed inNOTE

the helicopter for a cargo transport mission:

Perform step b. and c. only i

a. Doors

- Open.

lowered with accumulator pressur

b. Parking brake

- On.

b. APU accumulator

,500

psi or

c. Troop seats

- Stow.

more. If the pressu

2,500

psi,

d. Cargo compartment -Clean.

operate the hand pump

to bui

e. Tiedown devices

- Check, for type

. EMERG UTIL PRESS valve

- O

Figure

6Seq.uence Valve Operation

Change

6-31

55-1520-240-10

d. Ramp control valve lever - DN, allowingNOTEramp

to lower to a position of grounMomentary selection of the RAMP EMER

If the ramp is to be adjusted ttrol switch to then

DN position will

ground rest, or fully closed, approximately 5 seconds of the ramp a

in the retracted position, perdoor opening opera

tion sequence. The

(1) Sequence valve plunger - sequence of the

ramp can be halted du

second cycle by momentarily placing t

(2) Sequence valve plunger retainer pin

EMER control switch to the UP positi

Rotate to the horizontal position to lock

tinuous lowering of the ramp (longer

the plunger in.

seconds) can be achieved by holding t

2. Raise the ramp as follows:

EMER switch in the DN position unt

a. Sequence valve plunger-Checdesired ramp position is attained.

ramp and cargo door are to be closed.

b. RAMP EMER control switch

- DN

NOTE

tarily, then back to HOLD. The ram

Perform step b. only if accumulator pressure is

cycle can be halted by momentaril

used to raise the ramp.

RAMP EMER control switch to UP.

c. Repeat step b. if necessary, un

b. EMERG UTIL PRESS valve

- Open.

position is achieved, or hold the

c. Ramp control valve lever - UP,DN position u

ntil the ramp reache

to close. If accumulator pressure is not sufficient

position.

to raise the ramp, operate the hand pump.

2. Close the ramp as follows:

d. Ramp control valve lever

- STOP.

a. RAMP PWR switch.- EMERG.

CAUTION

b. RAMP EMER control switch - UP un

The ramp must be at or above floor level

closed, then back to HOLD.

during takeoffs and landings.

6-54. Manual Operation - Cargo Door.

6-53. In-Flight Operation.

Should the need arise to retract or ex

section of the ramp manually, insert the

The ramp can be operated at airspein figure 6-e. At speeds

19. Crank clockwise to retr

up to

60 knots, the ramp will open normally. At speeds

clockwise to extend.

above 60 knots, air pressure from within the cargo compart-

ment is required. To get this pressure, the vent blower can be

6-55. Preparation of General Cargo.

turned on or the upper section of the cabin door can be

opened.

Before loading cargo, it is advisable

cargo with regard to dimensions, weight

CAUTION

center of gravity, and hazards. This da

determining the placement of the load in

Do not attempt to manually operate the

in computing weight and balance. Refer

cargo door when the utility hydraulic system

is pressurized. Motor damage can result.

6-56. Cargo Dimensions.

Any item of cargo whic

appears to have critical dimensions fo

helicopter should be measured and chec

6-53.1. Ramp Emergency Control.

and compartment dimension limitations.

WARNING

6-57. Cargo Weight.

Package weight of indivi

items of cargo should be legibly stenc

The RAMP EMER control switch is intended

surface. If not provided, the weight mu

for emergency use only during smoke and

order to plan cargo placement, to calcul

fume elimination procedures. Inadvertent op-

and to compute helicopter weight and ba

eration of the cargo ramp and cargo door

rule applies to palletized cargo and ve

from the cockpit may result in injury to

personnel or damage to equipment.

6-58. Cargo Center of Gravity.

The center of gravit

(C.G.) of each item of cargo must be det

compute weight and balance by the stat

1. Open the ramp as follows:

rule, those items of cargo crated for tr

a. RAMP PWR switch

- EMERG.

with a C.G. If the C.G. is not

6-32

Change

TM 55-1520-240-10

marked, it can be determined by m6-61.hGeneralInstructionsfordLoading,Securing,

55-450-2.

and Unloading Cargo.

There are three prime factors to b

6-59. Vehicle Load.

loading the helicopter. These fact

The same general rules that are oand restraint. The weight of the c

apply to vehicle loading. In additremain within safe operatingrlimits

caps, and battery filler caps shorestrained from shifting during tak

Fuel tanks should be checked to sRefer to FM 55-450-2 to determine

above three-quarters capacity. Airshoring and restraint criteria.

expand at altitude and force fuel out through the filler neck,

creating a fire hazard. If fuel 6-62.Weight and Balance.

some fuel must be drained off befRefer to TM 55-1500-342-23 and fig

Also, check tire pressures and, ihelicopter GW/CG and complete

Form

prescribed limits.

6-63. Restraint.

6-60. Hazardous Cargo.

Items of cargo within the helicopte

Items of cargo possessing dangerforces which affect the,elicopter

such as explosives, acids, flammabcause the cargo to shifted

unless th

with extreme caution and in accomaintain helicopter balance and pre

regulations and TM 38-250.

cargo must be restrained from shift

Change

6-32.1/(6-32.2 blank)

TM 55-1520-240-10

cargo extends into two or three compartments, the

weight of the item should be proportionately distributed

in each compartment. The C.G. of the cargo load is

computed as follows:

a. Record the weight of cargo in each compartment.

b. Calculate the compartment moment by multiplying

the total weight in each compartment by the station

number of the compartment centroid.

c. Add the compartment moments.

d. Add the weight in all compartments.

e. Divide the sums of the cargo moments by the total

weight of the cargo. The result is the arm or the C.G.

location of the load.

6-66. Station Loading. Loading by stations provides

a more precise method of computing the C.G. of a load

and should be used whenever possible (fig. 6-21). To use

this method, it is necessary to know the C.G. of each

item of cargo. If the C.G. of an item is not marked, it can

be determined by the procedure given in FM 55-450-2,

Station loading requires that the C.G. of each item

placed in the helicopter coincides with a fuselage station

number. The C.G. of the load is calculated as follows:

a. Record the weight and station number of each item

of cargo.

b. Calculate the moment of each item by multiplying

the weight of the item by the station number of its C.G.

Figure 6-19. Cargo Door Cranking

c. Add the moment of each item to obtain the total

6-64. Load Planning.

load moment.

Before loading cargo, the placement of individual items

d. Add the weights of each item to obtain the total

of cargo in the helicopter should be planned and then

load weight.

checked to determine if the planned arrangement falls

within the C.G. limits. There are three basic steps

e. Divide the total load moment by the total load

involved in load planning. The first step is to decide

weight to obtain the arm or the C.G. location of the

which method will be used to compute the C.G. of the

load.

load. If the compartment method is to

be used, each

6-67. Vehicle Loading. The same procedures ob-

item of cargo must be assigned a location in one of the

served in cargo loading apply to vehicle loading.

three compartments. If the station method is to be used,

specific station locations must be assigned to each item

6-68. Shoring.

of cargo. The second step is to compute the C.G. of the

load. If the load consists of a number of items of cargo,

Shoring is used to protect the cargo floor and to

the compartment method should be used. If the load

distribute load pressure over a greater area of the floor.

consists of only a few bulky items, the station method

Shoring can often make the difference between being

should be used. The third step is to check if the C.G.

able to carry a given load and not being able to;

falls within the allowable limits. If it does, the cargo can

however, it is important not to exaggerate the effective-

be loaded; if not, the location of individual items should

ness of shoring. Some vehicles have a tread width too

be rearranged until an acceptable loading plan is ob-

narrow to allow the wheels to rest on the treadways. In

tained.

this case, shoring must be used to reduce the contact

pressure on the walkway to an allowable figure. In

6-65. Compartment Loading. Loading by compart-

general, shoring is required for all wheeled platforms

ments provides a rapid means of computing the C.G. of

and dollies and for any item of cargo whose contact

a load and can be used whenever the cargo load consists

pressure exceeds the floor limitations.

of a number of items. The helicopter cargo compart-

ment is divided into three compartments (fig. 6-20). The

6-69. Securing Cargo.

centroid, or center of balance, of each compartment is

located at station 181, 303, and 425, respectively. When

The helicopter is subjected to forces which result from

using the compartment method, it is assumed that the

air turbulence, acceleration, rough or crash landings,

weight of all the cargo in the compartment is concen-

and aerial maneuvers. These same forces act upon the

trated at the centroid of the compartment. If an item of

cargo in the helicopter and tend to shift the cargo unless

6-34

TM 55-1520-240-10

Figure 6-21. Station Loading

it is firmly secure. Forward motion of the helicopter is

which it keeps the cargo from moving. Forward restraint

the most rapid movement that will be encountered and

keeps the cargo from moving forward, aft restraint

is the strongest force that is likely to act on the cargo if

keeps the cargo from moving aft, and so on.

the helicopter is suddenly slowed or stopped in a crash

landing. Other forces tending to shift the cargo aft,

6-70. Restraint Criteria.

laterally, or vertically will be less severe. The amount of

restraint required to keep the cargo from moving in any

The following restraint factors are ultimate values and

direction is called the restraint criterion and is ex-

the minimum acceptable factors for crew and passenger

pressed in units of the force of gravity, or g’s. In each

safety.

case, the maximum force exerted by the item of cargo to

be restrained would be its normal weight times the

number of g’s of the restraint criteria. In order to safely

carry cargo, the amount of restraint applied should

equal or exceed the maximum amount of restraint

required. Restraint is referred to by the direction in

6-36

TM 55-1520-240-10

Direction

Restraint Criteria

NOTE

Forward

4.0 g’s

The HICHS can yield locally under the

Aft

2.0 g’s

above loads, but ultimate failure cannot oc-

cur; that is the cargo (e.g., pallet, ERFS)

Down

4.0 g’s

cannot become a flying object when the

2.0 g’s

above loads are applied. The above ultimate

Lateral

1.5 g’s

load factors shall be applied to the entire

HICHS. All other cargo will be restrained to

6-71. Restraint Devices.

the normal restraint criteria as stated in this

Refer to FM 55-450-2.

chapter.

6-72. Calculation of Tiedown Devices Required.

6-78. Loading Sequence.

Refer to FM 55-450-2.

Refer to table 6-4 to select the proper configuration for

6-73. Tiedown Methods.

system components during loading. Up to three pallets

Methods of applying restraint will vary depending on

may be winched or manually loaded on the system.

the type of cargo making up the load. Vehicles, crated

Loading clearances are shown in figures 6-22, 6-23, and

objects, and assorted items of general cargo will require

6-24.

different methods of application. (Refer to FM 55-450-2

6-79. Warehouse Pallets. Refer to table 6-4 to select

for restraint methods.)

the proper configuration for system components during

loading. Up to 8 to 10 warehouse pallets can be loaded

into the helicopter provided that the weight and C.G.

requirements are within the limits specified as follows.

Excessive tightening of the tiedown straps

The 40- inch side should be positioned across the

attached to the outboard row of tiedown

handling system so that the 48-inch side is on the

fittings will limit the effectiveness of the

outboard rail. Pallets may be winched or manually

isolated floor.

loaded. During loading, the pallet should be fork lifted

onto the ramp extension and balanced onto the ramp

rollers. On the ramp, it should be pushed on board.

6-74. Vehicle Tiedown. Because of the numerous

points of attachment available, vehicles are the items of

cargo easiest to tie down. An MB-1 chain device should

NOTE

be used to restrain vehicle loads. These devices should

All cargo must be properly restrained to

be fastened to the 10,000-pound tiedown fittings when-

ensure safe operation of the helicopter and

ever possible.

safety of personnel. Loads must be restrained

in accordance with procedures and guide-

6-75. Bulk Cargo Tiedown. Typical methods of re-

lines in FM 55-450-2, Helicopter Internal

straining large crates are shown in FM 55-450-2. If the

Loads.

crate is very heavy, an MB-1 tiedown device should be

used to provide forward restraint and should be fas-

tened to the 10,000-pound tiedown fittings.

Individual warehouse pallets may weight up to

3,700 lbs.

However, to maintain floor isolation, the sum of the

6-76. General Cargo Tiedown. General cargo

weights of longitudinally adjacent pallets must not ex-

tiedown methods are shown in FM 55-450-2.

ceed 4,300 lbs. For example, pallets weighing 2,100 lbs

or less may be loaded without discrimination; a mix of

6-77. 463 L Pallet/ Extended Range Fuel System

pallets weighing, for example, 3,000 lbs and 1,200 lbs,

(ERFS).

would require alternate loading of a 3,000 lb pallet and

The restraint criteria capability of a 463L pallet/ERFS

a 1,200 lb pallet. If the load consists entirely of pallets

loaded to 7,500 pounds is as follows.

weighing in excess of 2,150 lbs, the pallets must be

Direction

Load Factor

spaced longitudinally such that the distance, in inches,

between the forward edge of one pallet and the forward

Forward

6g plus 1.5g down

edge of the subsequent pallet will not be less than

Aft

3g plus 1.5g down

W/45.2 when

W is the average pallet load in pounds. For

Lateral

2.25g plus 1.5g down

example, load of pallets weighing 3,000 lbs each would

need to be spaced 3000/45.2 =

66 inches center-to-

Down

center apart. Pallets that are spaced longitudinally will

require tiedowns for longitudinal, lateral, and vertical

forces. In this situation there is no requirement to use

the barrier systems.

6-80. Wheeled Vehicles. Refer to table 6-4 to select

the proper configuration for system components during

6-37

TM 55-1520-240-10

loading. Winch or manually load the vehicles into the

e. Repeat as required.

helicopter.

6-85. Extended Range Fuel System (ERFS),

6-81. Personnel.

ERFS II and FARE Kit Weight and Balance

Data.

The internal cargo handling system (HICHS), is

compatible for personnel only or for both cargo and

Refer to figure 6-1, table 6-3 and 6-3.1.

personnel. If both are loaded, the cargo should be forward

The operator, upon configuration of ERFS II and FARE kit,

of the personnel for safety.

must compute various fuel amounts to calculate

6-82. Miscellaneous Cargo.

combinations of weight and balance matching the mission

requirements. table 6-3 lists the weights, ARM and

Place on a pallet or skid as desired. If a 6/E (463L) pallet

moments of ERFS II and FARE kit installations.

is used, secure the pallet with the locks or retractable

flanges. straps or chains may be used as required.

WARNING

6-83. Mixed Cargo.

Some combinations of ERFS II configuration

and auxiliary fuel load will cause the helicop-

Any of the previous cargos may be mixed as desired. The

ter to exceed weight and balance limits. It is

only limitation is space.

the responsibility of the flight crew to ensure

6-84. Load Dumping From Ramp.

the helicopter center of gravity remains with-

in operating limits at take-off and landing.

CAUTION

Standard configuration for the ERFS II consists of three

Damage to the helicopter or load could occur

tank assemblies, fuel transfer hose assembly, fuel control

when load dumping from the ramp. Make sure

panel, restraint system, FARE kit, and unusable fuel, with

taxi surface is level and free of obstacles.

Tank 1 C.G. at 250 inches, Tank 2 C.G. at 330 inches,

Tank 3 C.G. at 410 inches, and FARE kit C.G. at 464

Dumping from the ramp is not a routine operation, but

inches.

under urgent conditions can be accomplished as follows:

6-85.1. Restraint System Limits.

a. Helicopter at full stop.

b. Remove ramp extensions and rollers if installed.

The limitations of the restraint system are 8 G’s forward,

3 G’s aft, 8 G’s vertical, and 8 G’s lateral, measured with

c. Load released, but under control and moved to aft

each tank one half full of fuel.

cabin ramp with ramp slightly in up position.

6-85.2. Breaking Loads of Self Sealing Breakaway

WARNING

Valves.

Crew members must remain clear of load.

The breaking loads of the self sealing breakaway valves

d. Helicopter taxis forward at approximately 5 knots

utilized in the ERFS II fuel and vent assemblies are:

ground speed. When 5 knots is reached, the ramp should

moment bending 750 lbs (±150 lbs) at 7 inches, and

be lowered and load pushed out the rear f the helicopter.

tension 4,300 lbs.

Table 6-3. Extended Range Fuel System (ERFS) Weight and Balance Data

Configuration

Weights/Balance

Station

Moments/1000

Fuel Tank 1

511.3

230.0

117.6

Fuel Tank 2

511.3

290.0

148.3

Fuel Tank 3

511.3

350.0

178.9

Fuel Tank 4

511.3

410.0

209.6

FMCP

190

9.1

Vent Lines

320

4.8

Pump Discharge Lines

290

5.8

Feed Lines/Manifold

290

20.3

Forward Area Refueling

800

502

401.6

Equipment (FARE)

(2 Pumps, 2 Filters, and 2

Fuel Cans)

HICKS

878

379.9

333.5

3/463L Pallets (290 lbs ea.)

870

323

281.0

6-38 Change 14

TM 55-1520-240-10

Table 6-3.1. Extended Range Fuel System II (ERFS II) Weight and Balance Data

Item

Weight (LBS)

Station (ARM)

Moment/1000

Single-point Refuel Hose

23.0

240.0

5.5

Total Weight and Moment

23.0

5.5

ERFS II Tank 1 (Empty)

607.0

250.0

151.8

Unusable Fuel (5.5 gal JP-8)

37.0

250.0

9.0

Fuel Control Panel (FCP)

20.0

217.0

4.3

Vent Hose

10.0

235.0

2.4

Elect Harness, Hel to FCP

7.0

235.0

1.6

Elect Harness, FCP to Tank

8.0

238.0

1.9

Wiring Harness, Fuel Qty

5.0

240.0

1.2

Restraint Assembly

81.0

250.0

20.3

Total Weight and Moment

775.0

192.5

ERFS II Tank 2 (Empty)

607.0

330.0

200.3

Unusable Fuel (5.5 gal JP-8)

37.0

330.0

12.2

Elect Harness, FCP to Tank

8.0

278.0

2.2

Fuel Hose

15.0

285.0

4.3

Vent Hose

10.0

305.0

3.1

Restraint Assembly

81.0

330.0

26.7

Total Weight and Moment

758.0

248.8

ERFS II Tank 3 (Empty)

607.0

410.0

248.9

Unusable Fuel (5.5 gal JP-8)

37.0

410.0

15.2

Elect Harness, FCP to Tank

8.0

319.0

2.6

Fuel Hose

15.0

375.0

5.6

Vent Hose

10.0

385.0

3.9

Restraint Assembly

81.0

410.0

33.2

Total Weight and Moment

758.0

309.4

Fuel Hose, Main to ERFS II

29.0

363.0

10.5

Fuel Hose, Fuel Transfer

13.0

400.0

5.2

Total Weight and Moment

42.0

15.7

FARE Kit

592.0

464.0

274.7

(Pump Module, hose, cou-

plings, filters, meters, and

nozzles)

Total Weight and Moment

592.0

274.7

TOTAL ERFS II

2,948.0

1046.6

(including FARE) Weight

and Moment

Change 14

6-38.1/(6-38.2 blank)

TM 55-1520-240-10

Table 6-4. Loading Sequence Configuration

463L Pallet Configurations

Comment

Configuration

Component

Down

Load

Outboard Rollers

Warehouse Guides

Down

Ramp Extension/Ramp Jacks

In Place as Required

Ramp Extension/Ramp Extension

In Place as Required

Rollers

Locks

Up (Unlock)

Retractable Flange

Rotate Outboard (Unlock)

5k/10k Rings

Down (Stowed Position)

Restraint

Outboard Rollers

Warehouse Guides

Ramp Extension/Ramp Jacks

Ramp Extension/Ramp Extension

Rollers

Locks

Down (Locked)

Retractable Flange

Rotate Inboard (Locked)

5k/10k Rings

Flight

Outboard Rollers

Warehouse Guides

Ramp Extension/Ramp Jacks

Stow in Helicopter

Ramp Extension/Ramp Extension

Rotate Ramp Extension on Ramp,

Rollers

Rollers on Underside (Stowed Posi-

tion)

Locks

Retractable Flange

5k/10k Rings

Unload

Outboard Rollers

Warehouse Guides

Ramp Extension/Ramp Jacks

In Place as Required

Ramp Extension/Ramp Extension

In Place as Required

Rollers

Locks

Up (Unlock)

Retractable Flange

Rotate Outboard (Unlock)

5k/10k Rings

Warehouse Pallet Configurations

Comment

Configuration

Component

Outboard Rollers

Down

Load

Warehouse Guides

Ramp Extension/Ramp Jacks

In Place as Required

Ramp Extension/Ramp Extension

In Place as Required

Rollers

Locks

Down (Unlocked)

Retractable Flange

Rotate Outboard (Unlock)

5k/10k Rings

Restraint

Outboard Rollers

Warehouse Guides

6-39

TECHNICAL MANUAL MAINTENANCE MANUAL FOR ARMY CH-47D HELICOPTER (1992) - page 10