MD Helicopters 369-500, Инструкция по техническому обслуживанию

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CSP-HMI-3
MD Helicopters, Inc
.
MAINTENANCE MANUAL
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97-01-00
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Neither this document nor any part hereof may be reproduced or transferred to
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purpose except as specifically authorized in writing by MD Helicopters, Inc.
Copyright
©
1999 − 2016 by MD Helicopters, Inc.
HEADSET − MICROPHONES, HEADSET ADAPTERS AND HEADSET
CABLES
DESCRIPTION AND OPERATION
1. Description and Operation
The pilot's headset-microphone plugs into a
jack located on the forward side of the canted
bulkhead. The jack is part of a headset cable
assembly incorporated into the wiring harness.
The headset cable assembly is wired to an ICS
control panel installed at the pilot's station
thru TB7. To communicate with the crew over
the interphone or to transmit to other aircraft
or ground stations over the COMM radios, the
pilot actuates a RADIO-ICS rocker switch on
his cyclic stick and speaks into the micro­
phone. The middle (relaxed) position of the
rocker switch is the listening position. The
rocker switch is wired to the ICS control panel
thru TB5. In some helicopters, the copilot also
plugs his headset directly into the jack of a
headset cable assembly, and communicates
and transmits using the RADIO-ICS rocker
switch on his cyclic stick. In some helicopters,
an observer plugs his headset into the jack of a
headset cable assembly wired directly to a
third ICS control panel installed at the
observer station. The observer may communi­
cate over the interphone and transmit over the
COMM radios in the same manner as the pilot
and copilot, using his headset-microphone and
a RADIO-ICS toggle switch; the toggle switch
functions in the same manner as the rocker
switches located on the pilot's and copilot's
cyclic sticks.
In most helicopters, the copilot's and passen­
gers' headsets must interface with the ICS by
means of adaptors. A headset adaptor is a
coiled cord with a RADIO/ICS switch and jack
on one end and a plug on the other end. The
headset-microphone is plugged into the jack
end, while the other end is plugged into one of
several jacks located on the forward and aft
sides of the canted bulkhead. Each jack is part
of a headset cable assembly incorporated into
the wiring harness. The headset cable assem­
blies are wired to the ICS control panel thru
TB7. The copilot communicates over the
intercom and transmits over the COMM radios
using his microphone and the RADIO-ICS
switch on his adaptor. If the copilot plugs his
headset-microphone into the jack without
using an adaptor, he must communicate and
transmit using the RADIO-ICS rocker switch
on his cyclic stick. The passengers may
communicate over the intercom using the
RADIO-ICS switch on their adaptors, but do
not have access to the COMM radios for
transmission.
In some helicopters, the copilot and observer
have footswitches which enable them to
transmit without having to use their RADIO-
ICS switches. The footswitches are wired to
the ICS control panels thru TB100.
NOTE:
Refer to ICS installations listed in the
optional equipment table to determine
which headset-microphones, headset adap­
tors, and headset cable assemblies are com­
patible with which installations.
A. Headset − Microphones
(Ref. Figure 1) Either one of two optional types
of headset-microphones (carbon or dynamic
microphone) is used with VHF communica­
tions installations. Each type contains two
earphones attached to a coiled retractable cord
with a headset plug. The headset plug contains
a standard U-174/U phone plug to mate with
the headset jack of an adaptor (Ref. Figure 2),
or with the headset jack of a cable assembly
(Ref. Figure 3). A noise-cancelling microphone
is mounted on the end of an adjustable wire
boom on the headset. Each of the two ear­
phones on the headset is encircled with a
padded headband. Consult the optional
equipment table for specific applications (Ref.
Sec. 01-00-00). Consult the ICS wiring
diagrams in this manual for wiring informa­
tion.
B. Headset Adaptors
(Ref. Figure 2) Each headset adaptor consists
of a switch and jack assembly case with an
attached coiled cord. The case contains a
RADIO-ICS switch and a headset jack. The
neutral (middle) switch position is the listen
position. The jack is a four-contact phone jack
that mates with the standard U-174/U phone