Transponder Operating Controls and Indicators
MASTER six-position, pull-to-turn, rotary switch.
OFF - Removes power from control panel and transponder (protected pull-to-turn).
STBY - Applies power to control panel and transponder, but disables transponder from
transmitting. Control panel is operational and monitors the operator s selections. Puts TCAS in
Standby. Returns FAIL message if BIT is run in STBY.
NORM - Enables transponder to reply to all enabled modes (M-1, M-2, M-3/A, M-C, M-4, or
M-S). Mode S defaults to "enabled" during power-up if aircraft is on the ground (Mode S
TA - Enables transponder to reply to all enabled modes (M-1, M-2, M-3/A, M-C, M-4, or M-S).
Enables TCAS processor, if installed, to provide Trafic Advisory (TA) warnings.
TA/RA - Enables transponder to reply to all enabled modes (M-1, M-2, M-3/A, M-C, M-4, or
M-S). Enables TCAS processor, if installed, to provide Trafic Advisory and Resolution Advisory
EMER - Enables transponder to generate an emergency code in all SIF modes and Mode S. In
addition, the TCAS processor will be enabled to operate in TA mode (if operational) (protected
Eight Character Alphanumeric Display With power applied, provides visual indication of loaded
codes and equipment status. Display is incremented through either the Mission Menu or
Maintenance Menu functions via the menu selection switch Select A (SEL A) or Select B
(SEL B), respectively.
SEL A/SEL B (Menu Selection Switch) spring loaded three-position switch
SEL A - Enables selection of Mission Menu functions. Enables E-TCAS, M1 and M3/A code data,
and ATC and TCAS Broadcast modes to be displayed and changed. Momentary (up) position.
Middle (null) - Enables normal operation of display.
SEL B - Enables selection of Maintenance Menu functions. Enables display intensity, M2 code
data, Mode S data, and maintenance functions to be displayed and changed. Enables and
disables ANT TEST and CP TEST. Momentary (down) position.
S1, S2, S3, and S4 spring loaded three-position switches.