TM 1-1510-218-10 3-59 CAUTION The  KLN  90B  fuel  calculations  are  based on the present rate of fuel flow, the present groundspeed,  the  present  distance  to  the destination  airport  along  the  programmed route,   and   the   amount   of   fuel   onboard entered  at  departure.    Before  takeoff,  the unit  must  be  properly  initialized  with  the amount   of   fuel   on   board.      Since   many factors   influence   the   required   amount   of fuel to reach the destination, check the fuel pages often for significant changes.  Some factors     affecting     the     amount     of     fuel required are power changes, altitude changes, headwind/tailwind component changes, and routing changes.  (a)  OTH   5   Page.         The   OTH   5   page displays   the   following   information.      Refer   to   Figure 3-75. OTH 5 KLFT   LBS FOB:   1800 REQD    740 L FOB  1060 RES:    500 EXTRA   560 Figure 3-75.  OTH 5 Page 1.   The     destination     waypoint.          An arrow is displayed to the left of the identifier    if    the    waypoint    is    the active waypoint. 2.   The fuel units as received from the AETM. 3.   The fuel presently on board (FOB).   To   change    the    present    fuel    on board: a.     Turn to the OTH 5 page. b.     Press the left  CRSR button to turn on the cursor function. c. Enter     the     current     fuel     on board using the left inner and outer knobs. d.     Turn the cursor function off. 4.   The    fuel    required    to    reach    the destination waypoint at the current rate  of  fuel  flow  and  the  present groundspeed (REQD). 5.   The landing fuel on board (L FOB) is  the  original  fuel  on  board  minus the  total  fuel  required  to  reach  the destination. 6.   The  desired  fuel  reserve  (RES)  is the amount of reserve fuel the pilot has   entered.      The   fuel   must   be entered in the same units displayed on the first line.  To enter the  reserve,  press  the  left    CRSR button, rotate the left outer knob to move    the    cursor    over    the    RES field.   Use  the  left  inner  and  outer knobs   to    enter    the    desired    fuel quantity.        Press    the    left    CRSR button   to   turn   off   the   left   cursor function. 7.   The calculated extra fuel (EXTRA) is   the   landing   fuel   on   board   (L FOB) minus the fuel reserve (RES). (b)  OTH   6   Page.         The   OTH   6   page displays   the   following   information.    Refer  to  Figure 3-76. 1.   The  endurance  (ENDUR)  in  hours and   minutes.      The   endurance   is calculated based on the amount of fuel remaining after subtracting out the  reserve  (RES)  entered  on  the OTH  5  page  or  the  OTH  6  page from the present fuel on board. OTH 6 FUEL DATA ENDUR 2:10 RANGE  580 NM/LB 0.44 RES:   500 Figure 3-76.  OTH 6 Page