TM 1-1510-225-10 3D-67 calibrated  airspeed  isn’t  known,  use  the indicated airspeed. 4.   Use the left outer knob to move the cursor to  the  first  ALT  position,  and  then  enter the  indicated  altitude  using  the  left  inner and  outer  knobs.    If  the  indicated  altitude was   previously   entered   on   the   CAL   1 page, it will already be displayed. 5.   Turn the left outer knob to move the cursor to  the  first  BARO  position  and  then  enter the  current  altimeter  setting  using  the  left inner   and   outer   knobs.      If   the   altimeter setting  was  made  on  the  CAL  1  page,  it will already be displayed. 6.   Rotate   the   left   outer   knob   to   move   the cursor to the first TEMP position, and then enter  the  outside  air  temperature  (in  ºC) by  using  the  left  inner  and  outer  knobs.   The  first  digit  of  the  temperature  is  either zero  (0)  if  the  temperature  is  above  zero or  a  minus  (-) if the temperature is below zero.  For maximum accuracy, the total air temperature  should  be  entered.    This  is the  temperature  of  the  air  including  the effect of heating due to movement through the   air.      Because   of   the   two    types   of temperature, a temperature entry made on the  CAL  1  page  is  not  transferred  to  the CAL  2  page.    The  TAS  is  now  displayed as illustrated in Figure 3D-97. 7.   Press the left  CRSR button to turn off the left cursor function. CAL 2     TAS CAS:  187KT ALT:24000FT BARO:29.92” TEMP: -32^o C TAS   265KT Figure 3D-97.  CAL 2 Page NOTE If the AETMS is installed and interfaced to the KLN 90B, the OTH 9 page displays the TAS for the present conditions.  c.   The Calculator 3 Page.    The  CAL  3  page  is used  to  calculate  the  wind  direction  and  speed.    In addition,  the  headwind  or  tailwind  component  of  the wind is displayed.  Refer to Figure 3D-98. CAL 3    WIND TAS   261KT HDG    343^o HDWND  21KT WIND  042^o t        53KT Figure 3D-98.  CAL 3 Page 1.   Select the CAL 3 page on the left side. 2.   Press the left  CRSR button to turn on the cursor function. 3.   Enter  the  TAS  by  using  the  left  inner  and outer   knobs.      If   the   CAL   2   page   was previously used to calculate the TAS, it will already be displayed. 4.   Use the left outer knob to move the cursor to  the  first  HDG  position,  and  then  enter the  aircraft’s  heading  using  the  left  inner and outer knobs. The headwind (HDWND)  or  tailwind  (TLWND)  and  the wind direction and speed are now displayed.  The wind direction is relative to true North. 5.   Press the left  CRSR button to turn off the cursor function. NOTE Wind calculations are only correct when an accurate  heading  and  true  airspeed  have been entered. If    the    KLN    90B    is    interfaced    with    the AETMS,   line   three   of   the   CAL   3   page   is blank.    Heading  is  automatically  inputted and used in the wind calculation. If    the    KLN    90B    is    interfaced    with    the AETMS,  the  OTH  9  page  displays  present wind information directly. d.  The Calculator 4 page.  The CAL 4 page is used  to  determine  vertical  navigation  descent/ascent