TM 1-1520-218-10 3C-206 climb, or whenever the aircraft is out of the operating altitude range of the radio altimeter. (2)   Hundred   Foot   Increment   Aural   Altitude Advisories   ( Mode   2).      The   aural   advisories   "One Thousand,    Nine    Hundred,    Eight    Hundred,    Seven Hundred,  Six  Hundred,  Five  Hundred,  Four  Hundred, Three Hundred, Two Hundred, One Hundred" indicate that  the  aircraft  is  at  the  associated  radio  altitude  in feet   AGL.      This   advisory   is   cancelled   when   valid information   from   the   radio   altimeter   is   lost,   during climb, or whenever the aircraft is out of the operating altitude range of the radio altimeter. (3)   Aural "Localizer" Advisory (Mode 3).   The aural advisory "Localizer" indicates that the aircraft has deviated   from   the   center   of   the   localizer   beam   in excess  of  1.3  to  1.5  dots.    The  localizer  advisory  is armed when a valid localizer signal is detected and the aircraft is below 1000 feet AGL.  It will be repeated no more that three times at 4-second intervals unless the aircraft is returned to less than 1.3 to 1.5 dots from the center of the localizer course.  The localizer advisory is disabled  when  a  valid  localizer  signal  has  been  lost, during   climb,   below   the   decision   height   set   on   the radio   altimeter,   or   if   the   navigation  receiver  is  not tuned to a localizer frequency. (4)   Aural  "Check  Gear"  Advisory  (Mode  4).   The  aural  "Check  Gear"  advisory  indicates  that  the aircraft   has   descended   to   500   feet   AGL   and   the landing  gear  is  not  down.    This  advisory  is  repeated once at 100-foot intervals down to 100 feet AGL. (5)   Aural    "Glideslope"    Advisory    (Mode    5).   The   aural   advisory   "Glideslope"   indicates   that   the aircraft  has  exceeded  1.3  to  1.5  dots  above  or  below the  center  of  the  glideslope  beam.    The  glideslope advisory  is  armed  when  a  valid  glideslope  signal  is detected  and  the  aircraft  is  below  1000  feet  AGL.    It will be repeated no more than three times at 4-second intervals unless the aircraft is returned to less than 1.3 to   1.5   dots   from   the   center   of   the   beam.      The glideslope  advisory  is  disabled  upon  loss  of  a  valid glideslope   signal,   during   climb,   on   a   localizer   back course,   below   the   decision   height   set   on   the   radio altimeter or, if the navigation receiver is not tuned to a localizer  frequency.    This  advisory  is  inhibited  by  the weight on wheels strut switch. (6)   Aural Advisory "Minimum, Minimum" (Mode  6).     The  aural  advisory  "Minimum,  Minimum" indicates   that   the   aircraft   is   at   the   radio   altitude selected by the crew using the radio altimeter indicator DH   knob.      This   advisory   is   cancelled   when   valid information   from   the   radio   altimeter   is   lost,   during climb, whenever the aircraft is above 1000 feet AGL, or whenever the aircraft is out of the operating altitude range of the radio altimeter. (7)   Aural "Altitude, Altitude" Advisory (Mode 7).       The    aural    advisory    "Altitude,    Altitude" indicates the approach to a pre-selected altitude as the aircraft  reaches  a  point  1000  feet  from  the  selected altitude  or,  after  reaching  the  selected  altitude,  when the   aircraft   deviates   more   than   250   feet   from   the selected altitude. (8)   Aural  "Check  Trim,  Check  Trim,  Check Trim"   Advisory.      The   aural   advisory   "Check   Trim, Check  Trim,  Check  Trim"  indicates  that  the  autopilot has had a trim failure. (9)   Aural   "Autopilot"   Advisory.      The   aural advisory   "Autopilot"   indicates   that   the  autopilot  has disengaged. d.  Emergency  Procedures.     If  an  emergency or   malfunction   makes   it   necessary   to   disable   the GPAAS,   pull   the    GPAAS   POWER   circuit   breaker located  on  the  instrument  panel.    GPAAS  audio  may be turned off by pressing the VOICE OFF switch. 3C-32.  TRAFFIC ALERT AND COLLISION AVOIDANCE SYSTEM (TCAS II). a.   System Overview. (1)   The Traffic Alert and Collision Avoidance System is an airborne system that interrogates mode A/C  and  mode  S  transponders  in  nearby  aircraft  and uses  the  replies  to  identify  and  display  potential  and predicted   collision   threats   to   the   flight   crew.      The system  protects  a  volume  of  air  space  around  your own aircraft.  Aural and visual advisories are provided to the flight crew to assure adequate separation when a system analysis of the intruding aircraft closure rate, derived from transponder replies, predicts a penetration of the protected airspace.  The TCAS II is controlled   through   the   TTC-920   Transponder/TCAS control panel located on the pedestal. (2)   Traffic   alerts   and   resolution   advisories are    indicated    on    the    TVI-920    Transponder/TCAS Display.  Traffic alerts provide the flight crew with the relative  bearing  and  distance  to  intruding  aircraft  that are  approximately  40  seconds  from  Closest  Point  of Approach  (CPA).    This  alert  provides   aid  in  visually acquiring  the  intruding  aircraft.    No  maneuvers  are commanded.    The  resolution  advisory  provides  threat resolution    information    in    the    form    of    a    vertical maneuver    (corrective)    or    restricted    vertical    speed range (preventive) that will increase aircraft separation when  the  threat  aircraft  is  approximately  25  seconds from CPA.