TM 1-1520-240-10
4-3-16
Figure 4-3-12. Center Cargo Hook Loading Pole
(Typical)
and emergency release mechanisms. The normal mech-
anisms can be operated by either pilot or by the hoist
operator. In an emergency, both hooks can also be re-
leased from the cockpit through a dedicated emergency
release circuit or manually by the hoist operator. A
knurled knob on the side of each hook allows the hook to
be opened by a ground crewman. A spring-loaded keep-
er prevents accidental loss of cargo through slippage of
sling rings. Each hook has a hook-loaded sensor. The
sensor will close and light a hook loaded advisory light
when the hook load exceeds approximately 150 pounds.
Stops on the hook allow the hook to swing approximately
80_ between full forward and full aft and approximately
50_ full right to full left.
4-3-11. Cargo Hook Controls.
The cargo hook control can be operated from the cockpit by
a switch on each cyclic stick grip and switches on the over-
head panel (fig. 4-3-3). The hooks can be operated from the
cargo compartment by a switch on the winch/hoist control
grip (fig. 4-3-7) and switches on the hoist operators panel
(fig. 4-3-8). Normal power to control the cargo hook system
is supplied by the 28-volt DC bus, through the CARGO
HOOK NORM RELEASE PWR and CONT circuit breakers
on the No. 2 PDP. Power to operate and control the emer-
gency release is provided by the 28-volt essential bus
through the CARGO HOOK EMER RELEASE PWR and
CONT circuit breakers on the No. 1 PDP.
a.
Cargo Hook MSTR Switch. The CARGO HOOK
MSTR (master) switch is on the CARGO HOOK panel
(fig. 4-3-3) of the overhead panel. The switch has three
positions marked ARM, OFF, and RESET. When the
switch is set to ARM, power is applied to the CARGO
HOOK RELEASE switches on the cyclic sticks and also
to the CARGO HOOK ARMING switch at the hoist opera-
tor’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 pan-
el 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 HOOK ARM Switch. A CARGO HOOK
ARM (arming) switch is on the hoist operator’s panel (fig.
4-3-8) in the cargo compartment. The hoist operator’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.
d.
CARGO HOOK RELEASE Switches. A CARGO
HOOK RELEASE switch is on each of the following: the
pilot’s and copilot’s cyclic grip, and the winch/hoist con-
trol grip. Any one of these switches can be used to oper-
ate the cargo hooks. Each of these switches are the
momentary type. When either the pilot’s or copilot’s CAR-
GO HOOK RELEASE switch is pressed with the CARGO
HOOK MASTER switch at ARM, the hook or hooks se-
lected on the HOOK SELECT switch will open. The for-
ward and aft hooks will open, then close. The center
hook, if selected, will open and remain open until the
cargo hook MASTER switch on the overhead panel is set
to OFF or the cargo hook ARM switch on the hoist opera-
tors panel is set to RESET.
