TM 1-1510-218-10 2-57 NOTE Both switches shall be off during crossfeed operation. (4)   Fuel   Transfer   Control   Switches.       Two switches, placarded    AUX  TRANSFER  OVERRIDE  / AUTO  C D T1 and  AUX XFER OVRD / AUTO  T2 , on the  fuel  management  panel  control  operation  of  the fuel  transfer  pumps.    During  normal  operation,  both switches are in   AUTO,  which  allows  the  pump  to  be automatically  actuated  by  fuel  flow  to  the  engine.    If either    transfer    system    fails    to    operate,    the    fault condition   is   indicated   by   two   illuminated   MASTER CAUTION   lights   on   the   glareshield   and   a   steady illuminated yellow  #1 or #2 NO FUEL XFR light on the caution annunciator panel. (5)   Fuel Crossfeed Switch. The fuel crossfeed   valve   is   controlled   by   a   3-position  switch located   on   the   fuel   management   panel,   placarded CROSSFEED OFF.  Under normal flight conditions the switch is left in the OFF position.   During 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 is placarded for fuel    selection    with    a    simplified    diagram    on    the overhead  fuel  control  panel.    Place  the  standby  fuel 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,  to  energize  the crossfeed valve and energize the standby pump on the side     from     which     crossfeed     is     desired.        During crossfeed     operation,     auxiliary     tank     fuel     will     not crossfeed   if   the   FUEL   FIREWALL   valve   is   closed.   When the crossfeed mode is energized, a  green FUEL CROSSFEED   light    on    the    caution/advisory    panel, Figure     2-17,     will     illuminate.         Crossfeed    system operation  is  described  in  Chapter  9.    The  crossfeed valve   is   protected   by   a   5-ampere   circuit   breaker, placarded    CROSSFEED    VALVE,    located    on    the overhead circuit breaker panel. g.  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  on  each  engine  firewall.      The   firewall  shutoff valves close automatically 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  battery  bus,  which  is connected   directly   to   the   battery.      The   valves   are protected  by  circuit  breakers,  placarded   FIREWALL VALVE   #1   or  # 2,   on   the   overhead   circuit   breaker panel,  Figure  2-16, and   FIREWALL  SHUTOFF  #1 or #2 on the hot battery bus circuit breaker board. h.  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.      Refer   to   Table   2-4   for   their locations. Table 2-4.  Drains and Their Locations DRAIN LOCATION Leading edge tank Outboard of nacelle underside of wing Integral tank Underside  of  wing  forward of aileron Firewall fuel filter Underside of cowling forward of firewall Sump strainer Bottom    center    of    nacelle forward of wheel well Gravity feed line Aft of wheel well Aux tank At wing root just forward of the flap (2)   An    additional    drain    for    the    extended range fuel system line extends through the bottom of the   wing   center   section   adjacent   to   the   fuselage.   Anytime the extended range system is in use, a part of the   preflight   inspection   would   consist   of   draining   a small  amount  of  fuel  from  this  drain  to  check  for  fuel contamination.  Whenever the extended range system is removed from the aircraft and the fuel line is capped off  in  the  fuselage,  the  remaining  fuel  in  the  line  shall be drained. (3)   Each    ferry    fuel    tank    has    a    10-foot 1/4-inch flex hose with a quick drain installed in the aft end.  When the ferry fuel system is in use, the preflight inspection  also  includes  draining  a  small  amount  of fuel  from  these  drains  to  drain  off  any  moisture  that may have been inadvertently introduced into the tanks.   Place  the  aft  end  of  the  hoses  out  through  the  cabin