TM 1-1500-204-23-1 3-8. Hydraulic     Fluid     Servicing.          Hydraulic     fluid servicing    precautions    are    explained    in    the    following paragraphs. WARNING To  avoid  contamination,  do  not  use previously  opened  cans  of  hydraulic fluid.  A new sealed can of fluid must be opened and used.  When opening can,    clean    top,    and    use    a    clean sharp, unplated instrument to prevent contamination. a. Do    not    overfill    reservoir    or    spill    fluid    in surrounding   areas.      When   fluid   is   spilled,   absorb   with clean rags. b. When filling reservoirs, extreme care shall be taken  to  ensure  that  no  dirt  or  foreign  matter  enters  the system. c. Refer     to     applicable     aircraft     maintenance manual for additional servicing and maintenance instructions.  Use only specified hydraulic fluid. 3-9. Pneumatic System Servicing.  Safety precautions for  servicing  pneumatic  reservoirs  are  contained  in  the following paragraphs. a. Never   use   pressure   oxygen   to   inflate   gear shock struts, pressure accumulators, etc. b. Use    only    clearly    labeled    compressed    air cylinders or compressed air hoses of known origin. c. Ensure   that   locking   mechanism   on   aircraft valve  stem  is  engaged  prior  to  installing  hose  to  valve stem.  Always engage locking mechanism after servicing. d. Fill  system  slowly  to  reduce  heat  generated by filling too rapidly. e. Exercise care not to overcharge the system. f. Completely discharge pressure prior to removing a component from the system. 3-10.  Engine   Operation.      For   operation   and   specific instructions   on   a   particular   fixed   or   rotary   wing   Army aircraft,   refer   to   the   applicable   maintenance   manual. Safety  procedures  and  general  operating  procedures  for reciprocating   and   turbine   engines   are   contained   in   the following paragraphs. a. Safety  Procedures.    Safety  procedures  prior to  starting,  during  starting,  during  engine  operation,  and after   operating   engines   are   covered   in   the   following paragraphs. (1) Safety procedures prior to starting.  The following safety procedures should be accomplished prior to starting. (a) Head    aircraft    so    that    exhaust blast is directed to least inhabited areas. (b) Place  approved  chocks  fore  and aft of main landing gear wheels. (c) Clear    aircraft    and    surrounding areas of covers, tools, rags, work stands etc , and remove mooring ropes. (d) Secure  access  doors  by  closing or    removing    prior    to    ground    testing    turbine-powered aircraft engines. (e) Do   not   allow   personnel   on   any external   portion   of   an   aircraft   during   engine   start   or operation. (f) Station    ground    crew    member, equipped    with    a    carbon    dioxide    or    equivalent    fire extinguisher   to   one   side   and   forward   of   engine   being started.    This  crew  member  will  observe  for  fire  and  fire hazards, such as fuel from overflow lines, fuel/oil leakage, chock slippage, and other irregular conditions. CAUTION If  aircraft  utility  fire  extinguisher  is utilized  for  an  engine  start,  another fire   extinguisher,   rated   capacity   of 10-B  or  more,  will  be  located  within 50   feet   of   all   fixed   or   rotary   wing Army aircraft.  Fire fighting capability must be maintained. NOTE If ground crewmember does not have radio communication, he must stand in view of aircraft operator. (g) When appropriate, station a responsible  ground  crewmember  off  to  one  side,  away from  danger  areas,  and  aft  of  operating  turbine  powered aircraft,  to  warn  approaching  traffic.    Use  a  danger  flag when necessary. 3-16