TM  55-1510-221-10 Table 2-11. Standard Alternate and Emergency Fuels ENGINE ARMY  STANDARD  FUEL ALTERNATE   TYPE EMERGENCY  FUEL TYPE *MAX.   HOURS PT6A MIL-T-5624 MIL-T-5624 MIL-G-5572 150 Grade  JP-4 Grade  JP-5 Any  AV  Gas *  Maximum  operating  hours  with  indicated  fuel  between  engine  overhauls  (TBO). 2-91. FILLING FUEL TANKS. a. Army  Standard  Fuels.  Army  standard  fuel is JP-4. W A R N I N G b.  Alternate   Fuels,   Army   Alternate   fuels   are JP-5  and  JP-8. Prior  to  removing  the  fuel  tank  filler  cap, the  hose  nozzle  static  ground  wire  shall  be attached  to  the  grounding  lugs  that  are located  adjacent  to  the  filler  opening. Fill  tanks  as  follows: C. Emergency  Fuel.  Avgas  is  emergency  fuel and  subject  to  150  hour  time  limit. 2-94.  USE  OF  FUELS. Fuel  is  used  as  follows: a. Attach  bonding  cables  to  aircraft. b. Attach  bonding  cable  from  hose  nozzle  to ground  socket  adjacent  to  fuel  tank  being  filled. Do  not  insert  fuel  nozzle  completely  into fuel  cell  due  to  possible  damage  to  bottom of  fuel  cell.  Nozzle  should  be  supported and   inserted   straight   down   to   prevent damage  to  the  anti-siphon  valve. c. Fill  main  tank  before  filling  respective  aux- iliary  tanks  unless  less  than  a  full  fuel  load  is desired. d. Secure  applicable  fuel  tank  filler  cap.  Make sure  latch  tab  on  cap  is  pointed  aft. e. Disconnect  bonding  cables  from  aircraft. 2-92. DRAINING MOISTURE FROM FUEL SYS- TEM. To  remove  moisture  and  sediment  from  the  fuel system,  12  fuel  drains  are  installed  (plus  one  for  the ferry  system,  when  installed). 2-93.  FUEL  TYPES. Approved  fuel  types  are  as  follows: a. Fuel  limitations.  There  is  no  special  limita- tion  on  the  use  of  Army  standard  fuel,  but  certain limitations   are   imposed   when   alternate   or   emer- gency  fuels  are  used.  For  the  purpose  of  recording, fuel  mixtures  shall  be  identified  as  to  the  major component  of  the  mixture,  except  when  the  mixture contains  leaded  gasoline.  The  use  of  any  fuels  other than   standard   will   be   entered   in   the   FAULTS/ REMARKS  column  of  DA  Form  2408-13,  Aircraft Maintenance  and  Inspection  Record,  noting  the  type of  fuel,  additives,  and  duration  of  operation. b. Use of Kerosene Fuels. The use of kerosene fuels  (JP-5  type)  in  turbine  engines  dictates  the  need for  observance  of  special  precautions.  Both  ground starts  and  air  restarts  at  low  temperature  may  be more  difficult  due  to  low  vapor  pressure.  Kerosene fuels  having  a  freezing  point  of  minus  40  degrees  C (minus  40  degrees  F)  limit  the  maximum  altitude  of a  mission  to  28,000  feet  under  standard  day  condi- tions. c. Mixing  of  Fuels  in  Aircraft  Tanks.  When changing  from  one  type  of  authorized  fuel  to another,  for  example  JP-4  to  JP-5,  it  is  not  necessary to  drain  the  aircraft  fuel  system  before  adding  the new  fuel. d.  Fuel  Specifications.  Fuel   having   the   same NATO   code   number   are   interchangeable.   Jet   fuels conforming  to  ASTM  D-1655  specification  may  be used  when  MIL-T-5624  fuels  are  not  available.  This usually  occurs  during  cross-country  flights  where  air- craft  using  NATO  F-44  (JP-5)  are  refueling  with NATO  F-40  (JP-4)  or  Commercial  ASTM  Type  B fuels.  Whenever  this  condition  occurs,  the  engine 2-81