TM 1-1520-238-10
3-1
CHAPTER 3
AVIONICS
Section I. GENERAL
3.1 DESCRIPTION.
This chapter covers the avionics equipment configuration
installed in the AH-64A helicopter. It includes a brief de-
scription of the avionics equipment, its technical charac-
teristics, capabilities, and locations. For mission avionics
equipment, refer to Chapter 4, Mission Equipment.
The communications equipment provides intercommu-
nication between crewmembers and VHF AM-FM and
UHF AM radio communication. If installed, VHF FM Single
Channel Ground and Airborne Radio Set (SINCGARS) is
also provided. The navigation equipment includes an Au-
tomatic Direction Finder (ADF), a Doppler Navigation Sys-
tem (DNS) and a Heading Attitude Reference Set
(HARS). Transponder equipment consists of an Identifica-
tion Friend or Foe (IFF) receiver transmitter. Height above
ground level is provided by a radar altimeter. Each anten-
na is described with its major end item. Antenna locations
on the airframe are shown (fig 3-1).
3.2 AVIONICS EQUIPMENT CONFIGURATIONS.
Avionics equipment configurations are shown in Table
3-1.
3.3 AVIONICS POWER SUPPLY.
Power to operate most of the avionics equipment is pro-
vided by the emergency dc bus. This allows for backup
battery power that is used in the event of a complete elec-
trical failure. External power may also be applied. Func-
tion selector should be OFF before applying helicopter
power.
3.4 EMERGENCY OPERATION.
If both generators or both transformer-rectifiers (T/R’s)
fail, turn off all nonessential radio equipment to prevent
excessive drain on the battery.
