7. Essential electrical equipment - On (in- dividually until fire source is isolated). 8. Land as soon as practicable. e.  Smoke  and  Fume  Elimination.  To  elimi- nate  smoke  and  fumes  from  the  aircraft,  perform  the following: 1. 2. Crew oxygen - 100% and ON. Bleed  air  valve  switches  -  ENVIRO OFF. 3. 4. 5. Vent blower switch - AUTO. Aft vent blower switch - OFF. Cabin   temperature   mode   selector switch - OFF. 6. If smoke and fumes are not eliminated: Cabin pressure dump switch - CABIN PRESS DUMP. TM  55-1510-221-10 2. Land as soon as possible. d.  Electrical  Fire.  Upon  noting  the  existence or  indications  of  an  electrical  fire,  turn  off  all affected electrical circuits, if known. If electrical fire source is unknown, perform the following: 1.  Crew  oxygen  -  100%. 2. Master switch - OFF (visual conditions only). 3.  All  nonessential  electrical  equipment  - OFF. NOTE With loss of DC electrical power, the air- craft  will  depressurize. All  electrical instruments,  with  the  exception  of  the propeller RPM, Nt RPM, and TGT gages will be inoperative. 4.  Battery  switch  -  ON. 5.  Generator  switches  (individually)  - RESET, then ON. 6. Circuit breakers - Check for indication of  defective  circuit. As  each  electrical  switch  is  returned  to ON  (note  loadmeter  reading)  and  check for evidence of fire. NOTE Opening  storm  window  (after  depressuriz- ing)  will  facilitate  smoke  and  fume removal. 7. Engine oil pressure - Monitor. 9-21. FUEL SYSTEM. a.  Fuel  Pressure  Warning  Annunciator  Light Illuminated. Illumination of the #1 FUEL PRESS or #2 FUEL PRESS warning light usually indicates fail- ure of the respective engine-driven boost pump. Per- form the following: 1. Standby pump switch - ON. 2.  Fuel  pressure  warning  annunciator light - Check extinguished. 3.  If  fuel  pressure  warning  light  is  still illuminated:   Record   unboosted   time. b.  No  Fuel  Transfer  Caution  Light  Illumi- nated.  Illumination  of  a  #1  NO  FUEL  XFR  or  #2 NO FUEL XFR annunciator light with fuel remain- ing in the respective auxiliary fuel tank indicates a failure of that automatic fuel transfer system. Pro- ceed as follows: 1. AUX   TRANSFER   switch   (affected side)  -  OVERRIDE. 2. Auxiliary fuel quantity - Monitor. 3. AUX TRANSFER switch (after respec- tive  auxiliary  fuel  has  completely  trans- ferred)  -  AUTO. c. Nacelle Fuel Leak. If nacelle fuel leaks are evident, perform the following: 1. Perform engine shutdown. 2. Fire pull handle - Pull. 3. Land as soon as practicable. d.  Fuel  Crossfeed.  Fuel  crossfeed  is  normally used  only  during  single-engine  operation.  The  fuel from the dead engine side may be used to supply the live engine by routing the fuel through the crossfeed system. During extended flights, this method of fuel usage will provide a more balanced lateral load con- dition in the aircraft. For fuel crossfeed, use the fol- lowing procedure: 1. AUX  TRANSFER  switches  -  AUTO. 9-10