T-34C AIRCRAFT SYSTEMS FAMILIARIZATION
Cockpit Interphone Communication System
The Cockpit ICS allows communication between the two crewmembers. It is operable any time
the DC system is powered and is normally the first thing checked after the battery is turned on.
The Radio TRANSMITTER/INTERPHONE select switch, located on the inner face of the PCL,
permits communication to the other cockpit on the ICS or transmissions to other aircraft or
ground facilities on the UHF or VHF radio.
Two modes of operation are possible--the Manual mode (COLD MIKE - CM) in which the toggle
switch on the PCL must be depressed downward to utilize the ICS, or the automatic mode (HOT
MIKE - HM) in which a "hands-off" operation is possible. Selection of these two modes is done
from the audio control panel on the multifunction panel located on the right console (Figure 11-
1). Audio volume adjustment for that cockpit is made with the VOLUME knob. A third
operation is possible by holding the interphone function switch forward in the CALL position - all
other audio signals are reduced, the ICS volume is increased and both cockpit microphones are
automatically in "HOT MIKE."
Avionics Control Transfer System
An avionics control transfer system (Figure 11-2) is incorporated in the T-34C to allow one
cockpit to control all the communication and navigation equipment, except the ICS, VHF radio,
NACWS, and GPS. (This system also transfers control of the compass switches.) The avionics
master switch controls the electrical power to operate the avionics systems and is located only on
the front cockpit avionics control panel. The avionics master switch must also be on for operation
of the RMI. Once the pilot in front has turned the avionics master switch on, a green indicator
light will illuminate, indicating that avionics command is in the front cockpit (Figure 11-3).
Transfer of avionics command may now take place with the pilot in the aft cockpit pushing his
control transfer switch momentarily to the TAKE COMMAND position. The green indicator
light in the aft cockpit will now illuminate and the front cockpit light will be extinguished.
Avionics control may be taken, but not given.
NOT TRANSFERRED (GIVN)
Figure 11-2 Avionics Transfer