TM 1-1510-225-10 3C-12 (h)  Power    Warning    Flag    –    In    view, indicates   power   off,   caged   condition,   open   motor winding, or loss of power.  Retracted, indicates normal operation. (i)   Roll  Index  –  Rotates  with  aircraft  to provide  measurement  of  angular  displacement  by  the roll pointer during maneuvers. (3)   Standby Attitude Indicator Functions           ANG  .  Refer to Figure 3C-6. 1.  Attitude Sphere 2.  Roll Index 3.  Roll Pointer 4.  Horizon Line 5.  Pitch Knob 6.  Pitch Scale 7.  Symbolic Miniature Aircraft Figure 3C-6.  Standby Attitude Indicator  ANG (a)  Attitude Sphere – Moves with respect to  the  symbolic  miniature  aircraft  reference  to  display pitch and roll attitude. (b)  Roll  Index  –  Rotates  with  aircraft  to provide  measurement  of  angular  displacement  by  the roll pointer. (c)  Roll Pointer  – Indicates vertical in any roll attitude. (d)  Horizon    Line     –     Indicates     earth’s horizon relative to aircraft pitch attitude. (e)  Pitch  Knob  –  Rotated  to  adjust  the miniature aircraft. (f)   Pitch Scale – Measures pitch displacement of miniature aircraft. (g)  Miniature Aircraft – Represents aircraft   nose   and   wings.      Indicates   roll   and   pitch attitude  relative  to  the  horizon.    Adjustable  through pitch knob for varying pitch attitudes. 3C-16.  DATA NAV SYSTEM. a.     Introduction.      The   Data   NAV   equipment enables  the  operator  to  use  the  color  weather  radar indicator    to    display    radar    returns,    checklists,    or navigation  symbology/alpha-numeric.    The  navigation data  is  derived  from  external  VOR/DME,  or  TACAN devices   as   selected   by   the   two   HSI   source   push switches   located   outboard   of   each   HSI.      Refer   to Figure 3C-7. The  four  principal  display  modes  in  which  the radar  indicator  operates  are  Radar  Returns  (WXD), Navigation (NAV), Checklists, and Auxiliary. b.    Data NAV Switches and Controls.  (1)   OFF   /   NORM   INDEX   /   NORM   LIST   / WXD  /  EMER  INDEX  /  EMER  LIST  /  NAV  /  AUX.   Rotary    switch    used    to    turn    Data    NAV    Interface Computer off or on by selection of checklist, weather (WXD),  navigation  (either  NAV  or  with  weather),  or Auxiliary operation. (2)   NAV 1 – The pilot's navigation information  is  displayed  via  the  latching  push-button switch, NAV 1 (green). (3)   DES  IN  /  DES  OUT   –  Momentary  left- right  3-position  switch  used  to  move  the  designator along radial established by RAD control. (4)   NAV   2   –   Latching   push-button   switch used to select NAV 2 station (yellow). (5)   CS 1 – Latching push-button switch used to  select  course  line  (green)  and  readout  for   NAV  1 station. (6)   CS 2 – Latching push-button switch used to  select  course  line  (yellow)  and  readout  for   NAV  2 station. (7)   DES  NAV  1  /  DES  NAV  2.   Slide-switch used to select designator for  NAV 1 or NAV 2 station.