TM 55-1510-222-10 in  the  auxiliary  tank  for  that  side  will  not  be  available (usable) for crossfeed. 2. Standby pumps - Off. 3. Crossfeed switch - As required. 4. Fuel    crossfeed    annunciator    illuminated    - Check. NOTE With  the  fire  pull  handle  pulled,  the FUEL PRESS annunciator will remain illuminated   on   the   side   supplying fuel. 5. Fuel   pressure   annunciator   extinguished   - Check. 6. Fuel quantity - Monitor. e. NAC LOW Annunciator Illuminated. Illumination    of    the    #1    or    #2    NAC    LOW    caution annunciator     indicates     that     the     affected     tank     has approximately  30  minutes  of  usable  fuel  remaining  at sea   level,   at   normal   cruise   power   consumption   rate. Proceed as follows: WARNING Failure    of    the    fuel    tank    venting systems  will  prevent  the  fuel  in  the wing  tanks  from  gravity  feeding  into the   nacelle   tank.   Fuel   vent   system failure may be indicated by illumination   of   the   #   1   or   #2   NAC LOW  caution  light  with  greater  than 30 minutes of usable fuel indicated in the main tank fuel system.  The total usable   fuel   remaining   in   the   main fuel  supply  system  with  the  low  fuel caution  light  illuminated  may  be  as little   as   140   pounds,   regardless   of the    total    fuel    quantity    indicated. Continued flight may result in engine flameout due to fuel starvation. 1. Land as soon as practicable. 9-27.  ELECTRICAL SYSTEM EMERGENCIES. a. DC  GEN  Annunciator  Illuminated.    When  a DC GEN annunciator illuminates, perform the following: 1. Generator switch - OFF, RESET, then ON. 2. Generator switch (no reset) - OFF. 3. Mission control switch - ORIDE. 4. Operating loadmeter - 100% maximum. b. Both DC Generator Lights Illuminated (reset failed). 1. All nonessential equipment - Off. 2. Land as soon as practicable. c. Excessive Loadmeter Indication (over 100%).    If  either  loadmeter  indicates  over  100%,  per- form the following: 1. Battery switch - OFF (monitor loadmeter). 2. Loadmeter over 100% - Nonessential electrical equipment off. 3. Loadmeter under 100% - Battery switch ON. d. Inverter    Annunciator    Illuminated.        When either  #    or  #2  INVERTER.    annunciator  illuminates, perform the following: 1. Affected inverter switch - Off. e.      Instrument     AC     Annunciator     Illuminated. Illumination    of    the    INST    AC    warning    annunciator indicates   that   both   26   VAC   transformer   circuits   are inoperative.    The  primary  power  indicating  instruments, torque  and  fuel  flow,  will  be  inoperative.    Under  these conditions,  power  must  be  controlled  by  indications  of the N.  and TGT gages.  Perform the following: 1. N.  and TGT indications - Check. 2. Other engine instruments - Monitor. f. Circuit Breaker Tripped.  If a circuit breaker trips, perform the following: 1. Bus feeder breaker tripped - Do not reset. NOTE Circuit  breakers  should  not  be  reset more   than   once   until   the   cause   of circuit malfunction has been determined and corrected. 2. Nonessential circuit - Do not reset. 3. Essential circuit - Reset once. g. Battery  Charge  Annunciator  illuminated.    If the BATTERY CHARGE caution annunciator illuminates during normal cruise flight, perform the following: 1. Battery  ammeter  -  Check,  note  indication, and monitor for increasing load.  If load 9-10