TM 1-1510-225-10 3B-198 The  Stormscope  system  should  never  be used to attempt thunderstorm penetration.   The  FAA  and  AIM  recommend  to  avoid  by at least 20 miles any thunderstorm identified  as  severe  or  giving  an  intense radar echo. CAUTION Persistent clusters of two or more discharge   points  indicate  thunderstorms.   There are several atmospheric phenomena that  can  cause  isolated  discharge  points.   Clusters  of  two  or  more  discharge  points indicate   thunderstorm   activity   when   they reappear    persistently    after    clearing    the screen. Additionally, should the heading stabilization fail, it is necessary to press the CLEAR button for properly oriented data following an aircraft heading change. Press the   MENU  button  to  return  to  the  main menu. NOTE The date is set before the time. (4)   Time/Date Mode.  The TIME/DATE mode can   be   selected   only   from   the   main   menu.      The time/date mode menu displays four items: stopwatch, elapsed time, time of day, and day, month, and year.   Refer   to   Figure   3B-155.      When   first   selecting   the time/date mode, the stopwatch digits will be highlighted.    To  use  the  stopwatch  function,  press  the START  button  to  start  or  stop.    Pressing  the   RESET  button  will  immediately  reset  the  timer.    To  use  the elapsed    time    feature,    press    the    NEXT    button    to highlight the elapsed time digits and press the START button   to   start   or   stop   the   counter.      Pressing   the RESET button will reset the elapsed timer. Figure 3B-155.  Time/Date Mode To set the current date or the correct time, press the  NEXT  button to highlight the digits to be changed.   Press the  UP or DOWN button to step the digits to the proper   value.      When   either   the   time   or   date   are highlighted, the    RESET   and  START  button  legends are replaced with UP and DOWN. (5)   Options   Mode.    The  options  mode  can only  be  selected  from  the  main  menu.    The  system continuously    self-tests    many    functions.        Refer    to Figure 3B -156. Results are indicated by CONTINUOUS  TEST:  OK  or  FAULT.    CONTINUOUS TEST:   OK   indicates   that   all   internal   self-test  items have  been  operating  properly.    The  continuous  self- test  is  intended  to  advise  only  of  major  component failures.    The  pilot  initiated  self-test is more extensive than the continuous self-test and is recommended as a check   on   system   operation   whenever   thunderstorm activity is noted on the display.  Press the  TEST button when in the options mode to manually initiate the test. Figure 3B-156.  Options Mode WARNING