PRIMUS
r
1000 Integrated Avionics System
A28--1146--112--00
PRIMUS
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II Radio System
C--36
AD--51036--R2@
Tuning Backup Control Head
Figure C--16
Normal Mode
In the normal mode, the tuning backup control head can be used to
control the co--pilot’s COM 2 and NAV 2 frequencies. The frequencies
selected by a crew member using the tuning backup control head are
displayed on both the tuning backup control head and the No. 2 RMU.
Frequencies selected by the co--pilot on the No. 2 RMU, or by the pilot
using the No. 1 RMU in the cross--side operating mode, are also
displayed on the tuning backup control head. The normal mode is not
annunciated.
Emergency Mode
In the emergency mode, the tuning backup control head becomes the
exclusive source for frequency control of the COM 2 and NAV 2 units.
In this mode, No. 2 RMU inputs are inhibited, the tuning backup control
head annunciates EMRG, and the No. 2 RMU annunciates AUX ON
(this annunciation is adjacent to the COM 2 and NAV 2 annunciations).
If the pilot is operating the No. 1 RMU in the cross--side mode, AUX ON
is displayed on the No. 1 RMU as well.