TM 1-1510-224-10 NOTE Both  STANDBY  PUMP  switches  shall be  OFF  during  crossfeed  operation. The    loss    of    fuel    pressure    due    to failure    of    an    engine-driven    boost pump    will    illuminate    the    MASTER WARNING annunciators on the glareshield,   and   will   illuminate   the respective    #1    FUEL    PRESS    or    #2 FUEL    PRESS    annunciator    on    the warning  annunciator  panel.    Turning on the STANDBY PUMP will extinguish the FUEL PRESS annunciator.  The MASTER WARNING annunciators must be manually reset. (3)    Fuel    transfer    control    switches.        Two switches   on   the   fuel   management   panel   (fig.   2-20), placarded    AUX    XFER    OVRD    -    AUTO,    individually control   operation   of   the   fuel   transfer   pumps.      During normal   operation   both   switches   are   in    AUTO,   which allows the system to be automatically actuated.  If either transfer   system   fails   to   operate,   the   fault   condition   is indicated   by   the   MASTER   CAUTION   annunciators   on the  glareshield  and  a  steadily  illuminated  amber   #1  NO FUEL  XFR or   #2  NO  FUEL  XFR   annunciator   on   the caution annunciator panel. (4)          Fuel     crossfeed     switch.          The    fuel crossfeed   valve   is   controlled   by   a   3-position   switch located    on    the    fuel    management    panel    (fig.    2-20), placarded   CROSSFEED   -   OFF.      Under   normal   flight conditions  the  switch  is  left  in  the  OFF  position.    During emergency-single    engine    operation,    it    may    become necessary to supply fuel to the operative engine from the fuel system on the opposite side.  The crossfeed system Figure 2-23.  Auxiliary Fuel Tank Fuel Gage is  placarded  for  fuel  system  selection  with  a  simplified diagram  on  the  overhead  fuel  control  panel.    Place  the STANDBY   PUMP   switches   in   the   off   position   when crossfeeding. A lever lock switch, placarded CROSSFEED, is moved from the center  OFF position to the left or to the right, depending on direction of fuel flow. This    opens    the    crossfeed    valve    and    energizes    the standby   pump   on   the   side   from   which   crossfeed   is desired.      During   crossfeed   operation   with   firewall   fuel valve closed, auxiliary tank fuel will not crossfeed.  When the    crossfeed    mode    is    energized,    a    green     FUEL CROSSFEED annunciator on the caution/advisory panel will illuminate.  Crossfeed system operation is described in  Chapter  9.    The  crossfeed  valve  is  protected  by  a  5- ampere circuit breaker, placarded CROSSFEED, located on the overhead circuit breaker panel (fig. 2-9). f.  Firewall Shutoff Valves. CAUTION Do  not  use  the  fuel  firewall  shutoff valve to shut down an engine, except in  an  emergency.    The  engine-driven high-pressure fuel pump obtains essential   lubrication   from   fuel   flow. When   an   engine   is   operating,   this pump    may    be    severely    damaged (while  cavitating)  if  the  firewall  valve is closed before the CONDITION lever is     moved     to     the     FUEL     CUTOFF position. The  fuel  system  incorporates  a  fuel  line  shutoff valve  mounted  aft  of  each  engine  firewall.    The  firewall shutoff valves close when the fire extinguisher T-handles on   the   instrument   panel   are   pulled   out.      The   firewall shutoff   valves   receive   electrical   power   from   the   main buses,   and   also   from   the   hot   battery   bus   which   is connected   directly   to   the   battery.         The   valves   are protected     by     5-ampere     circuit     breakers,     placarded FIREWALL VALVE #1 and  #2,  on  the  overhead  circuit breaker panel (fig. 2-9). g.      Fuel   Tank   Sump   Drains.      A   sump   drain wrench  is  provided  in  the  aircraft  loose  tools  to  simplify draining a small amount of fuel from the sump drain. (1)   There are five sump drains and one filter drain in each wing (table 2-3). (2)      An   additional   drain   for   the   extended range fuel system line extends through the bottom of the wing  center  section  adjacent  to  the  fuselage.    Any  time the 2-48