TECHNICAL MANUAL MAINTENANCE MANUAL FOR ARMY CH-47D HELICOPTER (1992) - page 9
TM
55-1520-240-10
Figure 4-28.
Static Line Retriever System
4-30
TM 55-1520-240-10
the cyclic sticks and also to the CARGO HOOK
ARMING switch at the hoist operator’s station. OFF
position is used to close the mid cargo hook. RESET
position is used to turn off the FWD, MID, and/or AFT
HOOK OPEN caution capsule(s).
b. CARGO HOOK SEL Switch.
The CARGO
HOOK SEL (select) switch is on the CARGO HOOK
panel on the overhead switch panel. It is a five position
rotary switch marked HOOK SELECT. The switch
positions are FWD, MID, AFT, TANDEM, and ALL.
The position of this switch determines which hook or
hooks open when the CARGO HOOK RELEASE
switch on either cyclic stick or the hoist operator’s grip
is pressed.
c. CARGO HOOKARM Switch.
A CARGO HOOK
ARM (arming) switch is on the hoist operator’s panel
(fig. 4-25) in the cargo compartment. The hoist opera-
tor’s control panel CARGO HOOK ARM switch has
three marked positions: ARM, RMTE (remote), and
RESET. When the cockpit CARGO HOOK MASTER
switch is at ARM, and the hoist operator’s switch is
moved to ARM, power is applied to the CARGO
HOOK RELEASE switch, on the winch/hoist control
grip. When the switch is at RMTE, power is removed
from the CARGO HOOK RELEASE switch and the
cargo hooks can be operated from the cockpit only.
RESET position is used when the pilot requests that the
center cargo hook be closed from the hoist operator’s
station. When the switch is set to RESET, the CARGO
HOOK OPEN cautions will go out.
Figure 4-29. Center Cargo Hook Loading Pole
(Typical)
d. CARGO HOOK RELEASE Switches.
A CARGO
HOOK RELEASE switch is on each of the following:
spring-loaded keeper prevents accidental loss of cargo
the pilot’s and copilot’s cyclic grip, and the winch/hoist
through slippage of sling rings. Each hook has a hook-
control grip . Any one of these switches can be used to
loaded sensor. The sensor will close and light a hook
operate the cargo hooks. Each of these switches are the
loaded advisory light when the hook load exceeds
momentary type. When either the pilot’s or copilot’s
approximately
150 pounds. Stops on the hook allow the
CARGO HOOK RELEASE switch is pressed with the
hook to swing approximately
80° between full forward
CARGO HOOK MASTER switch at ARM, the hook or
and full aft and approximately
50° full right to full left.
hooks selected on the HOOK SELECT switch will
open. The forward and aft hooks will open, then close.
4-41. Cargo Hook Controls.
The center hook, if selected, will open and remain open
until the cargo hook MASTER switch on the overhead
The cargo hook control can be operated from the
panel is set to OFF or the cargo hook ARM switch on
cockpit by a switch on each cyclic stick grip and switches
on the overhead panel (fig. 4-20). The hooks can be
the hoist operators panel is set to RESET.
operated from the cargo compartment by a switch on
the winch/hoist control grip (fig. 4-24) and switches on
the hoist operators panel (fig. 4-25). Normal power to
control the cargo hook system is supplied by the 28-volt
The forward and aft hooks may fail to open if
DC bus, through the CARGO HOOK NORM RE-
the slings are slack when the release sole-
LEASE PWR and CONT circuit breakers on the No. 2
noids are energized (a load of approximately
PDP. Power to operate and control the emergency
20 pounds is required for opening). The
release is provided by the 28-volt DC bus through the
hooks can be opened by selecting the desired
CARGO HOOK EMER RELEASE PWR and CONT
hook(s) and depressing the release switch as
circuit breakers on the No. 1 PDP.
the aircraft is lifted to apply tension to the
slings.
a. CARGO HOOK MSTR Switch.
The CARGO
HOOK MSTR (master) switch is on the CARGO
HOOK panel (fig. 4-20) of the overhead panel. The
e. CARGO HOOK EMERG Switch.
The emergency
switch has three positions marked ARM, OFF, and
cargo hook release switch is on the CARGO HOOK
RESET. When the switch is set to ARM, power is
control panel. It is a guarded switch and it is labeled
applied to the CARGO HOOK RELEASE switches on
EMERG REL ALL (emergency release all). The switch
4-31
TM 55-1520-240-10
Figure 4-30. Center Cargo Hook and Cargo Hook Release
4-32
TM
55-1520-240-10
Figure
4Forward and Aft Cargo Hooks
is used to simultaneously open the three hooks, if an
WARNING
emergency situation develops. The three hooks will open
regardless of CARGO HOOK MSTR or HOOKWhen the center cargo hook is opened with the
positions. Setting the switch to REL externalloadofftheground, the cargo hook
gency hook release relay. The relaywill whip back and forth.izes release
solenoids in the forward and aft hooks and a solenoid valve
in the center hook. The solenoid valve in theCAUTION
releases the aircharge stored in the lower half of the hydraulic
When the center cargo hook is opened using
actuator, transferring the charge to the upper (release) half of
the manual emergency release handle, the
the actuator to open the hook. After this method of opening
hook must be closed manually. No attempt
the hook, the hook actuat
2,000
to
should be made to close the hook using the nor-
2,100
psi. The emergency hook release relay will automati-
mal hydraulic or pneumatic method, since
cally deenergize after a 10 second time delay. This prevents
damage to the cargo hook can result.
damage to the hook release solenoids.
4-43. Manual Emergency Release Systems.
CAUTION
a.anual cargo hook release mechanisms requiring
Before external load operations, crewmem-
independent operation, (forward and aft and “D” ring).
The
bers shall familiarize themselves with the
center hook is equipped with a ma
manual emergency cargo release mechanism
hook release handle
(“D” ring), sec
installed on the helicopter.
assembly. It is used to release the
4-42. Manual Emergency Release Systems.
The
utility hydraulic or electrical sy
triple cargo hook system has two msioned cargo hook release lever con
systems configurations: one systemkeeps the hook locked in the closed
ring to release the center hook, aconnects the lever arm to the-
releas
ward and aft hooks. The other syplace on the support beam by metal c
mechanisms requiring activation ofdle is pulled upward, thellever mov
three hooks (fig. 4-30).
to allow the cargo hook to swing fre
Change
9
4-33
TM 55-1520-240-10
forward and aft hook release lever is located on the
right side of the rescue hatch. The manual release
lever for the forward and aft hooks is in the rescue
1. CARGO HOOK MSTR switch - ARM.
hatch. The handle is connected by cables to the manual
2. CARGO HOOK SEL switch
- FWD.
release mechanism in the forward and aft hooks. The
lever has three positions: vertical, forward, and aft. In
3. Press the CARGO HOOK RELEASE switch
the stowed position, the lever is pointing forward. The
on the pilot’s cyclic stick - Check that the
vertical position is the normal position when external
FWD HOOK OPEN caution capsule comes on
cargo is-carried on the forward or aft hook. The aft
and the hook opens.
spring-loaded-to-ready position releases the forward
NOTE
and aft hooks simultaneously, loaded or not.
The forward and aft hooks will not open unless a force is
b. Single handle cargo hook release system.
This
applied. As long as one of the CARGO HOOK RELEASE
switches are pressed, the forward and aft hooks will make a
release system incorporates the release mechanisms for
chattering sound. This sound indicates the hook solenoids
all three cargo hooks. The “D” ring on the center hook
are operating normally.
has been replaced with a cable routed to the release
4. CARGO HOOK SEL switch - MID.
lever on the right side of the rescue hatch. The lever has
the same functions and positions as the forward and aft
5. Press the CARGO HOOK RELEASE switch
release lever. Activation of the lever by pulling aft will
on the copilot’s cyclic stick. Check that the
open all three cargo hooks.
MID HOOK OPEN caution capsule comes on
and the hook opens.
4-44. Cargo Hook Cautions. The cargo hook caution
capsules are on the master caution panel. They are
6. CARGO HOOK SEL switch - Am.
labeled FWD HOOK OPEN, MID HOOK OPEN, and
F 7. CARGO HOOK switch on HOIST OPERA-
AFT HOOK OPEN. A lit caution capsule indicates that
TORS PANEL - ARM.
the corresponding hook has opened. The cautions can
be extinguished by setting the CARGO HOOK MSTR
F 8. Press the CARGO HOOK RELEASE switch
switch to RESET or by setting the CARGO HOOK
on the WINCH/HOIST CONTROL GRIP .
switch on the hoist operators panel to RESET.
Check that the AFT HOOK OPEN caution
capsule comes on and the hook solenoid acti-
4-45. Hook Loaded Advisory Lights. Two advisory
vates. RESET and release to OFF.
lights marked HOOK LOADED are on the CARGO
HOOK control panel (fig. 4-20). The lights are marked
9. CARGO HOOK MSTR switch - RESET and
HOOK LOADED. When on, the light indicates that the
release to OFF. Check all HOOK OPEN
corresponding (forward or aft) hook has a load of above
caution lights go out and the hooks close. Then
approximately 150 pounds on it. The lights are turned
set ARM.
on by sensors in the forward and aft hooks.
10. CARGO HOOK SEL switch - TANDEM.
11. Press the CARGO HOOK RELEASE switch
on the pilot’s cyclic stick. Check that the FWD
If the DUAL HOOK FAULT light indicates a malfunc-
tion of the forward or aft hook, releasing the load using
and AFT HOOK OPEN caution capsules come
other than the manual release handle is prohibited.
on and the forward and aft hook solenoids
activate.
4-46. Dual Hook Fault Caution. A caution capsule
labeled DUAL HOOK FAULT is on the master caution
12. CARGO HOOK MSTR switch - RESET and
panel. This light provides continuous monitoring of the
release to OFF. Check both HOOK OPEN
electrical continuity of the release solenoids in the
caution capsules go out and the hooks close.
forward and aft hook. When on, it indicates a loss of
Then set to ARM.
electrical release capability of the forward and/or aft
13. CARGO HOOK SEL switch - ALL.
hook in both normal and emergency modes. When the
capsule is on, loads on the forward or aft hooks can only
14. Press the CARGO HOOK RELEASE switch
be released by the manual release system.
on the copilot’s cyclic stick. Check that all
HOOK OPEN caution capsules come on and
4-47. Cargo Hooks Operational Check.
the hooks open or the solenoids activate.
15. CARGO HOOK MSTR switch - RESET and
release to OFF. Check all HOOK OPEN
When stowing or positioning the cargo hook, do not
cautions go out and the hooks close.
grasp the hook assembly by the synchronizing assembly
shaft. Serious injury can result if the hook is operated
16. To confirm safety of the cargo hook system,
while the hand is in this position. The nylon web strap is
the pilot, copilot, and flight engineer each
to be used when positioning or stowing the hook.
press a CARGO HOOK RELEASE switch to
Before external load operations, perform the following
attempt to open cargo hooks with the CARGO
check of the cargo hooks.
HOOK MSTR switch at OFF.
4-34
TM
55-1520-240-10
4-49. Emergency Operation of Cargo Hooks.
4-48. Normal Operation of Cargo Hooks.
Normal operation of the cargo hooks from the cockpit
Refer to Chapter 9 for emergency operation of cargo
or from the cargo compartment is as follows:
hooks.
1.
CARGO HOOK MSTR switch
- ARM. (If
4-50. Helicopter Internal Cargo Handling System
used from the cockpit or the cargo compart-
(HICHS).
ment.)
2.
HOIST OPERATORS PANEL CARGO
An internal cargo handling system is provided for quick
HOOK switch
- ARM. (If used from the
loading securing and unloading of palletized cargo (fig.
cargo compartment.)
4-32 and 4-34). The system consists of a set of rail
3.
HOOK SEL switch
- Rotate to hook or hooks
assemblies and guide roller assemblies that are secured
to be released.
to the helicopter floor. For descriptive information,
service/maintenance instructions, operation, installation
4.
CARGO HOOK RELEASE switch - Press.
and removal instructions, refer to TM 55-1680-358-12 &
(From either the cockpit or the cargo compart-
P.
ment.)
5.
Master caution panel - Check HOOK OPEN
The system has three main sections: a cabin section, a
cautions come on.
ramp section, and a ramp extension section (fig. 4-34).
6. Loads -
Check released. If the forward or aft
The cabin section has outboard rail/ rollers along both
hooks did not open because of sling slack,
sides of the cabin, and inboard guide rollers running
along the center of the cabin. There are six outboard rail
press the release switch and lift the helicopters
to apply a strain to the sling and pull the hooks
/ roller assemblies, three on each side of the cabin. Each
open.
of the six rail / roller assemblies has its own dedicated
Figure 4-32. HICHS with 463L Palletized
4-35
TM 55-1520-240-10
Figure 4-33. Fixture Configuration
4-36
TM 55-1520-240-10
location in the helicopter. The left and right side rail
4-52. System Configurations. The HICHS can be
/roller assemblies are symmetrically opposite. There are
placed in any of four configurations. These are loading,
four inboard guide roller assemblies mounted in the
restraint, flight, and unloading. Refer to Chapter 6 for
center of the cabin. All of the outboard and inboard
configurations applicable to 463L pallets, warehouse
roller assemblies are installed by being bolted to the
pallets, and wheeled vehicles.
existing tiedown fitting locations in the cabin floor.
To accomplish the configurations described above and
The system is equipped with a set of locking devices and
in the referenced tables, several components must be
tiedown fittings for securing loaded cargo.
set in a predetermined position. These components are
listed below in conjunction with the illustration that
NOTE
defines the component location and or position.
All cargo must be properly restrained to
a.
Outboard rollers -
fig, 4-33.
ensure safe operation of the helicopter and
the safety of personnel. Loads must be re-
b.
Warehouse pallet guides - fig. 4-33.
strained in accordance with procedures and
c.
Ramp support assembly - fig. 4-33.
guidelines in Chapter 6 and FM 55-450-2,
Helicopter Internal Loads.
d.
Pallet lock assembly - fig. 4-34.
e.
Retractable flange assembly - fig. 4-32.
The ramp section has two inboard roller assemblies
f.
10K fitting assemblies - fig. 4-35.
along the center of the ramp and two outboard guide /
roller assemblies along the sides of the ramp. A ramp
- fig. 4-35.
g. 5K fitting Assemblies
support assembly is used to support the ramp when
4-53. Hatch Access. Remove, if necessary, any cargo
loading or unloading the helicopter with the ramp in the
forward of sta 377.250 to at least sta 157.750.
horizontal position.
The ramp extension section has two ramp extension
Remove three centerline ring plug assemblies to free
roller assemblies and two ramp extension support as-
the forward hatch inboard guide roller assembly (fig.
semblies to support the ramp extensions when loading
4-34). Stow the removed parts ahead of sta 272.250. The
and unloading with the ramp in the horizontal position.
hatch is now accessible and the removed parts can be
re-installed by reversing the preceding steps.
4-51. HICHS Cargo Types. The HICHS allows rela-
tively quick and easy loading of pallitized cargo. The
4-54. System Stowage. Flip-up the outboard rail /
following pallet types may be used:
roller assemblies and secure the seat support tube as
shown in fig. 4-33. Secure loading pole to clips located at
a. Three 463L pallets, 88 x 108 inches.
the top of the buffer board between sta 300 and 400 on
b. Six HCU-12/E or HCU/C pallets, 54 x 88 inches.
right side of helicopter with quick release pin. Inboard
guide roller assemblies can be stowed on the floor
c. Eight to ten warehouse wooden pallets, 40 x
48
beneath the troop seats. Secure ramp extension rollers
inches.
to the underside of the ramp extensions with quick
The HICHS has provisions for locking and securing
release pins. Stow ramp extension supports on the left
463L pallets. This type of pallet does not-need to be tied
side of the helicopter in brackets mounted between sta
down but the cargo must be secured to the pallet.
520 and 534. Stow ramp support at sta 550 left side.
Combinations of different pallet types may be used.
Miscellaneous cargo and equipment may be carried
4-55. Load Configuration and Sequence. Chapter
providing that they do not exceed weight or floor
6 contains the detailed descriptions and procedures for
loading restrictions, and can be properly tied down.
load configuration and sequence.
4-37
TM 55-1520-240-10
Figure 4-34. Internal Cargo Handling System
4-38
TM 55-1520-240-10
Figure 4-35. Tiedown Fittings HICHS
4-39
TM 55-1520-240-10
SECTION IV
EXTENDED RANGE FUEL SYSTEM (ERFS) AND ERFS II
consists of five functional components: the fuel tank
WARNING
assembly with fuel and vent hoses, restraint system,
ERFS II Fuel Control Panel, and FARE kit assembly.
The ERFS is a non-crashworthy auxiliary fuel
References and illustrations provided describe the three
system. The use of non-crashworthy internal
tank and FARE kit installation. Power is supplied to the
extended range fuel system may compromise
ERFS II from the No. 1 DC BUS and No. 1 AC BUS
the helicopters crashworthiness and may in-
through LH Utility Receptacles and wiring harness to the
crease the risk of burns in a potentially sur-
ERFS II Fuel Control Panel. Refer to TM 55-1520-240-23
vivable accident.
and tM 1-1560-312-10 for installation and maintenance
4-56. Extended Range Fuel System.
procedures.
The ERFS provides mission flexibility as an extended
4-57. ERFS Capabilities.
range mission kit and a forward area refueling source. The
a. The ERFS provides up to 2320 gallons, (580 gallons
ERFS is mounted on the left side of the cabin between sta
maximum per tank) of usable fuel for extended range
109 and 450, depending on the helicopter CG limits. The
missions.
ERFS is a modular, interconnected system composed of
up to four 600 gal non-crashworthy metal tanks, four
b. The ERFS can be installed, operated, removed,
electrically operated fuel pumps, and a vent system with
transported, handled, and stored in climatic conditions of
associated wiring and plumbing. The tanks are secured
-32_C to +52_C.
using 5K and
10K pound cargo straps. The fuel
c. The ERFS can be installed and used in a one tank
management control panel (FMCP) is housed in an
or multiple tank configuration as the mission requires.
aluminum box and is mounted on the forward most tank.
Refer to TM 55-1560-307-13&P for installation, operation,
d. Fuel quantity can be accurately monitored in flight
and maintenance procedures.
within four percent of the actual quantity using the liquid
level indicators.
WARNING
e. The ERFS can be refueled using the splash fill or
pressure fill techniques.
Chains will not be used to tie down the
f.
The system can also be defueled using standard
ERFS.
equipment.
CAUTION
g. The ERFS has redundant fuel feed capability in all
FMCP will not be operated without fuel in the
pump/tank combinations.
tank(s), or with tank cam lever in the CLOSED
h. Fuel transfer pump system can operate with APU,
position.
engine, or external power applied.
CAUTION
i.
The ERFS can be used as a forward area refueling
equipment (FARE) system, providing 2320 gallons of fuel
A fuel sample is required before the first flight
for refueling other helicopters.
of the day.
4-57.1. Fuel Tank Assembly.
CAUTION
The ERFS II fuel tank assembly consists of an outer alu-
Hot refueling is not recommended.
minum honeycomb and fiberglass shell container, ballisti-
NOTE
cally self-sealing bladder, plumping module, fuel hose,
For clarity, the tanks are numbered front to rear
vent hose assembly, and ground cable. Each tank mea-
1,2,3,4. In order to maintain helicopter CG,
sures 58 inch L x 62 inch W x 64 inch H with the capacity
suggested tank burn is 4, 1, 3, 2.
of 800 to 820 gallons of usable fuel and empty weight of
approximately 607 pounds (fig. 4-36). ERFS II tanks are
4-56.1. Extended Range Fuel System II.
designed to be loaded and unloaded by four persons (with
The Extended Range Fuel System II (ERFS II) is an
restraint system in place) in no more than 10 minutes and
internal tank fuel system that provides the CH-47D with
require no tools. The tanks should not be unloaded with
the ability to fly for an extended period of time without
any quantity of remaining fuel. When the tanks are
having to land for refueling. The ERFS II may be installed
installed there is an aisle up the right side of the aircraft
in one, two or three tank applications in addition to the
which is approximately 25 inches wide. the plumbing mod-
Forward area Refuel Equipment (FARE) kit installation.
ule consists of an aluminum access cover secured to an
Through the use of a FARE kit, the CH-47D can also be
energy-absorbing aluminum tube or column. The in-tank
used to ferry fuel to forward areas to support refueling
plumbing components are attached to a column in the
operations of other aircraft and equipment. The system
center of the
4-40
Change 14
TM 55-1520-240-10
Figure 4-36. ERFS II Fuel Tank
Change 14
4-41
TM 55-1520-240-10
tank permitting easy removal and maintenance on com-
4-59. ERFS II Fuel Control Panel.
ponents. A 75 psi fuel cap, dual transfer pumps, fuel
All transfer of ERFS II fuel into the helicopter main fuel
quantity probe, fuel sampling tube, and fuel pressure
tanks is controlled by the ERFS II Fuel Control Panel (fig.
switch are the internal parts of each of the tanks. Refuel-
4-37). The control panel is located and mounted on the
ing the ERFS II tanks is performed by either the helicopter
forward most ERFS II tank facing forward. It has individual
Single Point Refueling System or gravity.
switches that control the operation of the transfer pumps
a. Fuel Hoses. An interconnecting fuel hose manifold
and circuit breakers to protect each of the pumps in the
connects the ERFS II tanks together. A two inch hose con-
tank. Illumination is controlled by a dimmer rheostat on the
nected at the forward end of the ERFS II fuel manifold is
fuel control panel and is night vision goggles (NVG) com-
connected to the helicopter Single Point Refueling Sys-
patible. Electrical cables run from cargo compartment AC
tem in the vicinity of STA 255 on the left side of the cargo
and DC utility outlets at STA 358 and 320 to the ERFS II
compartment. Fuel transfer hoses connected at the aft
fuel control panel, and from the panel to connectors on
end of the manifold carry fuel to the aircraft fuel system
each tank. A fuel quantity gauge is installed on the panel
quick disconnects at STA 380 on both left and right sides
to provide readings in pounds of fuel for the individual
of the cargo compartment.
tanks and their combined total fuel remaining.
CAUTION
4-60. Fuel Transfer to Helicopter Main Tanks.
Up to 4 OZ. of fuel can be trapped between the
a. Manual FUEL/DEFUEL valve in all installed ERFS II
closed “Dry Break” valves in the Unisex cou-
tanks - CLOSED.
plings. Care should be taken to minimize
NOTE
spillage of this trapped fuel when separating
the couplings.
An OPEN manual FUEL/DEFUEL valve on the
b. Vent Hose Assembly. Aircraft overboard vents and
transferring ERFS II tank will significantly re-
connections are installed on the left side of the cabin area
duce the transfer rate because of fuel circula-
through the fuselage at STA 254.0, 330.0, and 410.0.
tion inside the tank. An OPEN valve on a non-
Overboard fuel vent caps must be removed anytime inter-
transferring tank will result in fuel transfer into
nal fuel tanks are installed. Vent hoses are connected to
that tank if it is not full.
the tank vent line at the self-sealing breakaway valve on
top of the tank assembly and one of the three aircraft over-
b. Unisex valves in ERFS II fuel transfer hose assem-
board vent connections.
bly - OPEN.
CAUTION
c. Select the ERFS II tank from which fuel is to be trans-
ferred.
Trying to pressure refuel the tanks without
connecting the vent line could overpres-
d. PUMP switch for the selected tank - OVERRIDE.
surize the tanks.
Hold in this position until PRESS LOW light goes out (nor-
The vent hose assembly allows the venting to atmosphere
mally less than five seconds). When released, the spring-
of fuel vapor, thus providing vent air to relieve internal tank
loaded switch will return to the ON position and fuel trans-
pressures. Fuel hoses and manifold are self-sealing incor-
fer will continue.
porating Unisex couplings. Each Unisex coupling, ball-
e. Monitor the helicopter fuel indicators to verify fuel
cock valve, permits hose removal without fuel spillage.
transfer.
The manifold also provides connection to the FARE pump
module. The fuel/defuel valve is a manually operated
f.
PUMP switch for selected tank - OFF when directed
vented valve that simultaneously opens a high flow rate
by the pilot or when the PRESS LOW light illuminates.
fuel path in the fuel/defuel line, and a high flow rate vent
g. FUEL QUANTITY switch - Set to 1, 2, or 3 for se-
path out of the tank. The valve must be open for pressure
lected tank to confirm desired amount of fuel transferred.
refueling of the tanks, FARE operations, or suction defuel-
ing. An automatic fuel shutoff valve, with dual high level
4-61. Forward Area Refuel (FARE) Kit Assembly.
shutoff controls is located inside the tank. Inside each of
the tanks is an open vent valve to allow fuel to vent over-
The FARE kit contains a pump module with a self-priming
board in the event of high level shutoff valve failure.
pump rated at 120 GPM and Flowmeter. the pump can be
4-58. Restraint System.
used to either fuel or defuel the ERFS II tanks. The pump
Each tank restraint system consists of an aluminum frame
module easily mounts on any one of the tanks when used.
and straps of polyester webbing with connecting hard-
A manually operated valve reverses the fuel flow and
ware and ratcheting buckles. This system provides longi-
permits defueling of the hoses after FARE operation. Two
tudinal, vertical, and lateral restraint. the forward, vertical,
in-line, multiple cartridge filters capable of filtering out 5
and lateral restraint ratings are 8g’s and the aft rating is
micron absolute particulates are included as part of the
greater than 3g’s. Each of the buckles are connected to
FARE kit. The 45 inch x 44 inch x 35 inch container for
twelve 5,000 pound tiedown rings on the helicopter cargo
FARE component storage is secured to the cargo floor
floor.
(fig. 4-38).
4-42
Change 14
TM 55-1520-240-10
Figure 4-37. ERFS II Fuel Control Panel
Change 14
4-43
TM 55-1520-240-10
Figure 4-38. FARE Fuel System Schematic
4-44
Change 14
TM 55-1520-240-10
4-62. FARE Transfer.
g. FRE PUMP switch - REMOTE.
CAUTION
To begin FARE transfer.
Some fuel will remain trapped in the FARE
h. Remote Control Handle trigger switch - Squeeze.
pump module, suction hose, filters, and col-
When FARE transfer is complete:
lapsible hoses after suctioning and rolling of
the FARE hoses has been completed. To
i. FARE Valve Control Handle - SUCTION.
avoid spilling trapped fuel, the valves in the
Unisex couplings must remain closed and
j. Valves in the Unisex couplings adjoining the
the couplings capped after the FARE system
nozzle(s), and filter(s) - CLOSE. Remove nozzles and fil-
is disassembled. All trapped fuel should be
ters from dispensing hoses, replace dust caps, and stow
drained into an appropriate container when
in FARE container. Reconnect hoses. Valves in the Uni-
the operational situation permits.
sex couplings, except at nozzle end - OPEN. Valve in Uni-
sex coupling at far end of hose assembly - CLOSE.
WARNING
k. Remote Control Handle trigger switch - Squeeze to
suction fuel from hose assemblies and return it to tank.
The manually operated FUEL/DEFUEL valve
While the FARE pump is running, slightly open the Unisex
must be place din the CLOSED position fol-
valves at the nozzle ends of the collapsible hoses to per-
lowing FARE operation. Failure to do so
mit the pump to evacuate most of the fuel prior to rolling
could permit significant fuel leakage in the
the hose.
event of a crash and the vent self-sealing
breakaway valve fails to actuate.
l. Collapsible Fuel Hose Assemblies - Lift and tightly
a. Single-Point Pressure Refueling Hose Assembly -
roll from the nozzle end toward the pump module while the
Unisex valve at ERFS II tank - check CLOSE.
pump is suctioning fuel from the hose. Close the valves in
the Unisex couplings as they are reached in the disassem-
b. Valve in the base of the Unisex “T” coupling on tanks
bly process. Disconnect the hoses, replace dust caps,
that are NOT the fuel source - CLOSE.
and stowin the FARE container. Repeat this process until
c. Valve in the base of the Unisex “T” coupling on tank
all collapsible fuel hose assemblies are recovered.
that is the fuel source - OPEN.
m. Remote Control Handle trigger switch - Release.
d. Manual FUEL/DEFUEL Valve on the tank that is the
fuel source - OPEN.
n. FARE PUMP switch - OFF.
e. FARE Valve Control Handle - OFF-LOAD.
o. Manual FUEL/DEFUEL valve(s) - CLOSED.
f. Flowmeter DISPLAY button - Press until TOTAL 2
is displayed. Press and hold three seconds to zero batch
p. Valve in the base of the Unisex “T” coupling on all
total.
tanks - check OPEN.
Change 14
4-45/(4-46 blank)
TM
55-1520-240-10
CHAPTER
5
OPERATING LIMITS AND RESTRICTIONS
SECTION I GENERAL
5-1. Purpose.
derive maximum utility from the
cerning maneuvers, weight, and ce
This chapter identifies or refers to all important oper-
tations are also covered in this
ating limits and restrictions that shall be observed
during ground and flight operations.
5-3. Minimum Crew Requirement.
5-2. General.
The minimum crew required to fly
The operating limitations set fpilots, and flight engineer. Addi
the direct result of design anarequired, will be added at the d
experience. Compliance with thesemander,inlaccordanceewith perti
pilot to safely perform the as
the Army Regulations.
5-1
TM 55-1520-240-10
SECTION II SYSTEM LIMITS
5-4. Instrument Markings.
made in DA Form 2408-13 unless the rotor system accel-
erates to 111 percent or above. Even though no action is
5-5. Instrument Marking Color Codes. Operating lim-
required when RRPM exceeds 108 percent power off but
itations and ranges are identified by the colored markings
remains less than 111 percent, willful operation should
on the dials of the engine, flight and utility system instru-
not be conducted in this range.
712
Operation be-
ments. The RED markings on the dials of these instru-
tween 96 and 92 percent (MIN BEEP) is permitted when
ments indicate the limit above or below which continued
water taxiing.
operation is likely to cause damage or shortened life. The
GREEN markings on instruments indicate safe or normal
5-8. Inoperative Cruise Guide Indicator. Flight at or
range of operation. The YELLOW markings on instru-
below 98 percent RRPM with an inoperative cruise guide
ments indicate the time limited range or when special
indicator is prohibited.
attention should be given to the operation covered by the
instrument. Operation is permissible in the yellow range,
5-9. Starting and Shutdown Limits.
but should be avoided. BLUE is a maximum indication
associated with sustained operation of the related air-
The APU shall not be started with a tailwind in excess of
craft system for a prescribed period of time. Limitations
25 knots. Main engines shall not be started with a tailwind
(fig. 5-1) which are marked on the various instruments
in excess of 10 knots. The rotor blade start-up and shut-
are not necessarily repeated in the subsequent text.
down limits of Figure 5-7.1 shall be observed. If it be-
When further explanation of certain markings is required,
comes necessary to shut down in conditions outside the
refer to the specific area of discussion.
limits show in Figure 5-7.1, the following precautions are
recommended:
5-6. Instrument Glass Alignment. All instruments
with range markings on the glass have short white align-
a. Aircraft should be landed in an area which is clear,
ment marks extending from the dial glass onto the rim of
as level as possible, and at least 300 feet away from any
the indicator. These slippage marks appear as a single
vertical obstructions, abrupt changes in ground terrain,
line when limitation markings on the glass properly align
trees, bushes, fences etc.
with the proper increments on the dial face. However, the
slippage marks appear as separate radial lines when a
b. Aircraft should be oriented such that the wind
dial glass has rotated.
would be coming in at the left side. If the pilot is unsure
of the wind direction after landing, a crew member should
5-7. Rotor Limitations.
be dispatched beyond the rotorwash to make a true wind
direction determination before the engines are secured.
Refer to figure 5-1 for limitations. Should 108 percent
power off be inadvertently exceeded, no entry need be
5-2
Change 19
TM 55-1520-240-10
111
Figure 5-1. Instrument Markings (Sheet 1 of 5)
Change 19
5-3
TM 55-1520-240-10
Figure 5-1. Instrument Markings (Sheet 2 of 4)
5-4
TM 55-1520-240-10
Figure 5-1. Instrument Markings (Sheet 3 of 4)
5-5
TM 55-1520-240-10
Figure 5-1. Instrument Markings (Sheet 4 of 4)
5-6
TM 55-1520-240-10
SECTION Ill POWER LIMITS
5-10. Engine Rating and Power Level Limits.
107 percent is exceeded. An N1 overspeed can cause
overtemperature and/or overtorque. A power turbine
For variations in torque available with temperature and
(N2) overspeed may exist, depending on power being
pressure altitude, refer to the Torque Available charts
used, when
106 percent RRPM is exceeded.
in. Chapter 7.
5-13. Engine Temperature Limitations. See fig. 5-1
5-11. Emergency Power.
and
5-2.
Emergency power is only to
be used during actual
5-14. Fuel Limitations. Only those fuels listed in
emergency conditions. After 30 minutes of emergency
Chapter 2 shall be used. Emergency fuel shall not be
power time have accumulated, the engine must be
used for more than
six hours cumulative time.
inspected.
5-12. Engine Limitations. See fig. 5-1 for limitations.
5-15. Transmission Torque Limitations (Steady-
A gas producer (Nl) overspeed exists when an N1 of
State). See fig. 5-1 for limitations.
Figure 5-2. Operational PTIT Limits, T55-L-712 Engines
5-7
TM 55-1520-240-10
SECTION IV LOADING LIMITS
5-16. Center-of-Gravity Limitations.
c. The center cargo hook is limited to a maximum
load of 26,000 pounds.
See fig. 6-25 for center-of-gravity (CG) limits in terms of
gross weight (GW) and arm-inches (fuselage stations).
5-19. Winch/ Rescue Hoist Limitations.
5-17. Maximum Gross Weight.
a. The winch shall not exceed:
The maximum allowable operating gross weight is
50,000
(1) 3,000 pounds, straight line pull.
pounds.
(2) 6,000 pounds, one pulley.
5-18. Cargo Hook Limitations. The limits presented
(3) 9,000 pounds, two pulleys.
below are structural limitations only.
(4) 12,000 pounds, three pulleys.
a. The structural limit of the forward
and aft hook is
17,000 pounds each.
b. The rescue hoist is limited to a maximum
load of 600 pounds.
b. The maximum single load that can be suspended as
a tandem
load from the forward
and aft hooks is
25,000
c. Refer to Chapter 4 for system configuration
pounds.
and operation.
5-8
TM 55-1520-240-10
Section V. AIRSPEED LIMITS
5-20. AIRSPEED OPERATiNG LIMITS.
5-21.
Airspeed Limitations With an Inoperative
Cruise Guide Indicator.
The airspeed operating limits chart, fig. 5-5, shows the
maximum allowable airspeeds with an inoperative cruise
guide indicator.
5-22. Airspeed Limitations With An Operative or
Inoperative Cruise Guide Indicator.
The following airspeed limitations apply with an opera-
Figure 5-3. Tandem Hook Rigging Without
tive or inoperative cruise guide indicator:
Redundant Sling
a. Maximum airspeed in
sideward
flight is 45 knots.
b. Maximum airspeed in
rearward
flight is 45 knots.
c. Maximum
crosswind
or tailwind for hover is
45
knots.
d. Maximum airspeed with the lower section of the
cabin entrance door open and locked is
60 KIAS.
e. The rescue hatch door shall not be opened or closed
above
90 KIAS. Otherwise the limitations specified in a.
and b. above apply.
Figure 5-4. Tandem Hook Rigging With
Forward Hook Redundant Sling
f. The windshield wipers shall be shut off at airspeeds
above
130 knots.
5-25.
High Density Loads. Maximum airspeed
g. Cabin door escape panel - assure that airspeed is
with high density cargo (jeep, gamma goat, M114, M198)
less than 100 KIAS before closing door in flight.
is dependent on load weight and rigging procedure.
5-23.
External Cargo Airspeed Limits.
a. Tandem rigging:
5-24. Mil-Van Type Loads. Maximum airspeed
(1) Maximum speed for weights
up to
7000
with Mil-Van type load is dependent on load weight and
pounds is
120 KIAS.
rigging procedure. If a sling or hook should fail while carry-
(2) Maximum speed for weights
from
7000
ing a tandem load, limit airspeed to a maximum of
60
pounds to maximum weight is
Vh.
KIAS. When carrying large external loads, such as the Mil-
Van, maximum airspeed for sideward and rearward flight
b. Tandem rigging with forward redundant rigging or
is 20 knots.
both forward and aft redundant rigging: Maximum air-
speed is Vh for all weights up to maximum authorized.
a. Tandem rigging (fig. 5-3).
5-26. Longitudinal Cyclic Trim (LCT) Actuator
(1) Maximum airspeed for Mil-Van weight
up to
Airspeed Limits.
7000 pounds is
70 KIAS.
The airspeed operating limits chart, fig. 5-6, shows the
(2) Maximum airspeed for Mil-Van weight
from
maximum allowable airspeeds with either LCT, fully
7000 pounds to maximum load is
110 KIAS.
retracted. Do not manually extend the LCT beyond the
GND position on the cyclic trim indicators at indicated air-
b. Tandem rigging with forward redundant sling (fig.
speeds below 60 knots. Use of extended cyclic trim at low
5-4).
airspeeds will result in high aft rotor blade stresses.
(1) Maximum airspeed for Mil-Van weight
up to
5-27. Use of Airspeed Limitations Chart.
7000 pounds is
100 KIAS.
The use of these charts is illustrated by the example on
(2) Maximum airspeed for Mil-Van weight
from
each chart. To determine the maximum operating
7000 pounds to maximum load is at
Vh.
airspeed, it is necessary to know the free air temperature,
Change 2 5-9
TM 55-1520-240-10
(FAT), pressure altitude, (PA), and gross weight, (GW).
for GW below
50,000 pounds. Go to the insert graph
Enter the chart at known FAT, move right to known
and enter it at known GW. Move right to the sloping
PA, move down following the graph lines to known GW,
line, then deflect down and read speed increase. To
then move left and read maximum indicated airspeed. If
determine maximum operating airspeed, add this value
the cruise guide indicator is inoperative, two airspeed
to that previously determined.
limits must be determined and the lower limit used. One
5-28. AFCS Limitations.
is the structural limit based on GW; the other is based
on blade compressibility limit at lower temperatures.
The airspeed limit when operating on
single AFCS
is
After determining the structural limit, move up or down
100 KIAS or Vne, whichever is slower. The helicopter
to the dashed line representing FAT, then deflect left
may be operated with both AFCS off up to 160 KIAS or
and read airspeed. This airspeed should be increased
Vne, whichever is slower.
5-10
TM 55-1520-240-10
AIRSPEED OPERATING LIMITS
AIRSPEED
WITH INOPERATIVE CRUISE GUIDE INDICATOR
OPERATING
LIMITS
PROGRAMMED LONGITUDINAL CYCLIC TRIM 100% ROTOR RPM
CH-47D
EXAMPLE
WANTED
MAX INDICATED AIRSPEED FOR GIVEN
TEMP, PRESS ALTITUDE, AND GROSS
WEIGHT
KNOWN
FAT = -30°C
PRESS ALTITUDE = 8,800 FT
GROSS WEIGHT = 36,000 LB
ENTER FAT AT= -30 “C
MOVE RIGHT TO
PRESS ALTITUDE=.8,600
MOVE DOWN TO GROSS WEIGHT LINE
(38,000 LB), MOVE LEFT AND
READ IAS=148KT
MOVE DOWN TO TEMP LINE (-30°C)
MOVE LEFT AND READ IAS=125 KT
USE INSERT GRAPH TO ADJUST TEMP
LIMIT SPEED FOR CHANGE IN GROSS
WEIGHT.
ENTER AT GW=38,000 LB MOVE RIGHT,
THEN DOWN TO READ INCREMENTAL
SPEED INCREASE-4.3 KT (IAS).
NOW, IA8=125+4=129 KT AT
GROSS WEIGHT=38,000 LB.
USE LOWER VALUE AS MAXIMUM IAS.
MAX IAS-129 KT
Figure 5-5. Airspeed Limitations - Inoperative Cruise Guide Indicator
5-11
TM 55-1520-240-10
AIRSPEED OPERATING LIMITS
AIRSPEED
WITH RETRACTED LONGITUDINAL CYCLIC TRIM
OPERATING
LIMITS
CH-47D
NOTE: USE OF CRUISE GUIDE INDICATOR TO EXCEED
THESE AIRSPEED LIMITS PROHIBITED
EXAMPLE
WANTED
MAX INDICATED AIRSPEED FOR GIVEN
TEMP, PRESS ALTITUDE, AND GROSS
WEIGHT
KNOWN
FAT=20°C
PRESS ALTITUDE = 2,000FT
GROSS WEIGHT = 42,000 LB
METHOD
ENTER FAT AT 20°C, MOVE RIGHT TO
PRESS ALTITUDE=2,000 FT
MOVE DOWN TO GROSS WEIGHT LINE
(42,000 LB), MOVE LEFT AND
READ IAS=74 KT
Figure 5-6. Airspeed Limitations - Longitudinal Cyclic Trim Retracted
5-12
TM 55-1520-240-10
SECTION VI MANEUVERING LIMITS
5-29. Aerobatics Prohibition.
d. The maximum ground speed for running landings
is 60 knots.
Acrobatics arc prohibited with this helicopter.
e. The maximum nose-up attitude during landings is
5-30. Bank Limitations.
20°.
The following bank angle limits apply:
5-32. Flight Control Limitations.
a. With an operative cruise guide indicator, bank
When operating at or above an airspeed of 100 knots,
angles are as limited by the cruise guide indicator, but
the thrust control is not to be lowered at a rate which
no greater than
60 degrees. When operating with
alti-
exceeds 2.5 inches per second. There is no limiting rate
tude hold, limit bank angles to
45 degrees maximum.
for movement less than 2.0 inches.
b. With an inoperative cruise guide indicator, use the
bank angle limits defined by fig. 5-7.
5-33. Ground Operation Limitations.
a. To prevent droop stop pounding while taxiing,
5-31. Landing Limitations.
flight control movements are not to exceed
0.75 inch
a. The maximum rate of descent at touchdown for
right or left for the directional pedals,
2 inches longitu-
gross weights
up to
33,000
pounds is
492 feet per
dinally aft of neutral and
1.00 inch laterally right or left
minute.
for the cyclic stick, and not below the ground detent for
the thrust control rod.
b. The maximum rate of descent at touchdown for
gross weights from 33,000 to 40,000
pounds is
450 feet
b. When ground taxiing less than
75 feet of an
per minute.
obstruction, a blade watcher and taxi director shall be
positioned as shown in figure 8-1.
c. The maximum rate of descent at touchdown for
gross weights
above
40,000
pounds is
360 feet per
minute.
Figure 5-7. Bank Angle Limitations
5-13
TM 55-1520-240-10
SECTION Vll ENVIRONMENTAL RESTRICTIONS
5-34. Engine Inlet Screen Limitation.
enable safe flight in light-icing conditions. Continuous
flight in light-icing conditions below
5°C is not recom-
Refer to table 5-1 for information on engine bypass
mended since blade damage can occur from asymmetric
panel removal.
ice shedding. Intentional flight into known icing condi-
tions with rotor blade erosion protection materials
5-35. Flight Under Instrument Meteorological
installed is prohibited. Icing conditions include “trace,”
Conditions (lMC).
“light, “ “moderate,” and “heavy.”
This helicopter is qualified for flight in instrument
5-37. Thunderstorm Operation.
meteorological conditions provided the following condi-
tions exist:
To ensure adequate lightning strike protection, the
lightning protection cables and straps must be installed
a. Both AFCS are operational.
and intact on all rotor blades. If any lightning cables or
straps are missing or broken, avoid flight in or near
NOTE
thunderstorms, especially in areas of observed or antic-
Should one AFCS fail during IMC flight, the
ipated lightning discharges.
flight may be continued to destination.
Should both AFCS fail during IMC flight, a
5-38. Operation With Skis. If skis are installed, the
landing should be made as soon as practical.
following limits apply:
a. The maximum
allowable airspeed is limited to
130
knots indicated airspeed or Vne, whichever is lower,
b. Two vertical gyros and two vertical gyro indicators
regardless of gross weight.
(VGI) are installed and operative.
b. The maximum
allowable gross weight for
ground
5-36. Flight in Ice.
operation is
50,000 pounds.
Pitot tube and Advanced Flight Control Systems (AFCS)
c. The maximum
allowable rate of descent at touch-
yaw port heating, and windshield anti-icing systems
down in snow is
480 feet per minute at gross weights up
Table 5-1. Bypass Panel Removal Requirement
5-14
Change 4
TM
55-1520-240-10
to
33,000
poun
decreasing
linearly to
240
feet perd. The maximum t
5 knots when oper
minu
t
46,000
pounds gross weight. Foon hard prepared surfaces.
46.000 pounds to
50,000
pounds, the rate of descent is
240
feet per minute.
USE WHEN:
NOTE:
CHART B MUST BE USED IF
A WIND IS FROM 125° TO 015° (CLOCKWISE)
ANY OF THE CONDITIONS
RELATIVE TO NOSE OF AIRCRAFT
LISTED FOR CHART A ARE
AND
NOT MET.
B. AIRCRAFT IS ON CLEAR LEVEL
GROUND AND AT LEAST 300 FEET
FROM VERTICAL OBSTRUCTIONS OR
ANY SUDDEN TERRAIN CHANGES.
Figure
5
Rotor Blade Start-Up & Shutdown Limits
Change
9
5-15
TM 55-1520-240-10
SECTION Vlll WATER
OPERATION LIMITATIONS
5-39. WATER OPERATION LIMITATIONS.
landings are prohibited
when fuel in the main tanks is
less than 50 percent.
5-40. Night Operation on Water. Night operation
5-46. Rotor Starting and Shutdown Limitations.
on water is permissible provided:
Rotor starting or shutdown will not be conducted when
a. Both AFCS are operational.
water conditions exceed Sea State 1 or wind exceeds
6
knots. Maximum gross weight for starting and shutdown
b. Pilot and copilot radar altimeter systems are oper-
is 28,550 pounds.
ational.
c. A visible horizon is present at the landing site.
d. Two or more highly visible, stationary objects are
on the water surface to provide necessary visual cues for
landing.
5-41. Sea State Limits. Operation on water is re-
stricted to a maximum of Sea State 2. Refer to table 5-2
for information on sea states.
5-42. Operation Time Limit. Operation on water is
restricted to 30 minutes total flotation time without
draining the helicopter.
5-43. Grosss Weight Limitations. Maximum gross
weight for water operations is as follows:
a. Normal operations -
36,000 pounds.
b. Emergency rescue missions -
46,000 pounds.
5-44. Taxiing Limitations. Taxiing will not be con-
ducted in water conditions above Sea State
1 or in wind
above
6 knots. Fast taxiing will be conducted in a
straight line only and to a maximum speed of
10 knots
when the lower nose enclosure is left in the water.
5-45. Landing Limitations. Water landings can be
performed within the limitations presented on fig. 5-8.
The touchdown speeds presented do not reflect indi-
cated airspeed but actual forward velocity at touch-
down. Running landings will only be conducted onto
calm water. The ramp, lower rescue door, and main
Figure 5-8. Water Landing Speed Limitations lip
cabin door shall be closed during water landing. Water
To 46,000 Pounds Gross Weight
Table 5-2. Description of Sea States
SEA
WIND VELOCITY
AVERAGE WAVE
STATE SEA DESCRIPTION
WIND DESCRIPTION
(KNOTS)
HEIGHT (FT)
Sea like a mirror (calm)
calm
Less than 1
0.0
0
Ripples with appearance of scales; no foam crests
Light Air
1-3
0.05
(smooth)
1
Small wavelets; crests of glassy appearance, not
Light Breeze
4-6
0.2
breaking (slight)
2
Large wavelets; crests begin to break; scattered
Gentle Breeze
7-10
0.6
whitecaps
3
Small waves, becoming longer, numerous white-
Moderate Breeze
11-16
1.4
caps (moderate)
5-16
TM 55-1520-240-10
SECTION IX
ADDITIONAL LIMITATIONS
5-47. Additional Limitations.
5-53. Maximum Capacity and Usable Fuel.
5-48. Air-to-Ground Towing.
The maximum capacity of one ERFS II tank assembly is
Air-to-ground towing operations are prohibited.
825.5 US Gallons.
5-49. APU Operation.
The usable fuel in one ERFS II tank assembly is 800 US
APU operation in flight is prohibited except during emer-
Gallons when single point pressure refueled.
gencies.
NOTE
5-50. Pitot Tube and AFCS Sideslip Port Anti-Ic-
ing Limitation.
the usable fuel may be increased by 20 US
Gallons if the ERFS II tank is gravity refueled.
The PITOT switch shall not be on for more than 5 minutes
on the ground.
5-54. Maximum Pressure Refueling Rate.
5-51. Single Point Refueling.
The maximum pressure refueling rate should not exceed
The maximum rate for pressure refueling is 300 gal/min
300 GPM.
at 55 psi.
5-55. Maximum Fuel Pressure.
5-52. Extended Range Fuel System (ERFS).
The maximum fuel pressure should not exceed 55 PSI.
WARNING
5-56. Maximum Internal Pressure.
Installing the non-crashworthy/non self seal-
ing ERFS increases the potential for explo-
CAUTION
sion and burn injuries during a crash. There-
fore, the number of personnel on board the
Trying to pressure refuel the tanks without
helicopter should be kept to the minimum re-
connecting the vent lines could over pressur-
quired to perform the required mission.
ize the tanks.
Over water flights with ERFS should be limited to 5.6
The maximum pressure inside the ERFS II tank should
hours.
not exceed 5 PSI.
NOTE
All CH-47D Aircraft are authorized for NVG
5-57. Maximum Suction Defueling Pressure.
use when delivered with the exception of air-
craft S/N 84-24187 and prior which are re-
CAUTION
quired to have MWO 55-1520-240-50-3.
Conducting suction defueling at pressures
5-52.1. Extended Range Fuel System II (ERFS II).
greater than -11 PSIG could damage the
The following paragraphs contain important operating lim-
internal components of the ERFS II tank
its and restrictions that shall be observed during the op-
assembly.
eration of the ERFS II. Compliance with these limits will
allow the operator to safely perform the assigned missions
The maximum allowable suction defueling pressure is -11
and derive the maximum utility from the ERFS II.
PSIG.
Change 14
5-17/(5-18 blank)
TM 55-1520-240-10
CHAPTER 6
WEIGHT/BALANCE AND LOADING
SECTION I GENERAL
6-1. Purpose.
6-3. Classification of Helicopter.
This chapter contains sufficient instructions and data so
Army Model CH-47D is in Class 1. Additional directives
that the aviator, knowing the basic weight and moment
governing weight and balance of Class 1 aircraft forms
of the helicopter, can compute any combination of
and records are contained in AR 95-3, TM 55-1500-342-
weight and balance.
23, and DA PAM 738-751.
6-2. Helicopter Compartment and Loading Dia-
gram.
Figure 6-1 defines the compartments, shows the refer-
ence datum line, and depicts other information essential
for helicopter weight/balance and loading.
6-1
TM 55-1520-240-10
Figure 6-1. Aircraft Compartment and Loading Diagram
6-2
Change 14