SECTION I. GENERAL
The avionic systems in the CH 47D helicopters consist
of the communications equipment providing HF, VHF
AM/FM, and UHF-AM communications. The navigation
equipment includes LF-ADF, VOR ILS, Marker Beacon,
Doppler/GPS, and Omega. VHF-FM homing is provided
through the AN/ARC-201 FM communication radio.
Transponder equipment consists of an IFF receiver-
transmitter with inputs from the barometric altimeter for
altitude encoding. Absolute height is provided by a radar
altimeter. For mission avionics equipment, refer to Chap-
ter 4, Mission Equipment.
3-1-2. Avionics Equipment Configuration.
Equipment configuration in the CH-47D helicopter is
listed in table 3-1-1.
3-1-3. Avionics Power Supply.
Power to operate the avionics systems is supplied by the
No. 1 and No. 2 DC buses, the DC essential bus, and No.
1 and No. 2 115-volt and 26-volt AC buses (Chapter 2).
The No. 1 VHF AM/FM, interphone and UHF sets can be
operated by selecting the BATT switch to ON. To operate
the remaining avionics equipment, the APU generator or
the main helicopter generators, must be operating, or AC
ground power must be connected. All circuit breakers
must be in.