TM 55-1510-219-10 WARNING If  the  oxygen  system  pressure  is below  200  PSI,  do  not  attempt  to service system.  Make an entry on DA Form 2408-13. 4.  Insure  that  supply  cylinder shutoff valves on the aircraft are open. 5.  Fill system slowly to prevent overheating by adjusting    recharging    rate    with    pressure regulating valve on oxygen servicing unit. 6.    Close  pressure  regulating  valve  on  oxygen servicing    unit    when    pressure    gage    on oxygen system indicates the pressure obtained using the Oxygen System Servicing Pressure Chart (fig.  2-30). NOTE Fill oxygen system to 1800 PSI at 70°F.  For every degree above 70°, increase   pressure   3.5   PSI   to   a maximum   of   2000   PSI;   and   for every degree F below 70°, decrease pressure 3.5 PSI. 7.        Disconnect    oxygen    hose    from    oxygen servicing unit and filler valve. 8.  Install protective cap on oxygen filler valve. 9.  Install oxygen access door. 2-99.  GROUND HANDLING. Ground handling covers all the essential information concerning  movement  and  handling  (fig.    2-31)  of  the aircraft  while  on  the  ground.    The  following  paragraphs give, in detail, the instructions and precautions necessary to accomplish ground handling functions. a.  General Ground Handling Procedure.  Accidents resulting     in     injury     to     personnel     and     damage     to equipment    can    be    avoided    or    minimized    by    close observance  of  existing  safety  standard  and  recognized ground handling procedures. Carelessness or insufficient knowledge of the aircraft or equipment being handled can be fatal.  The applicable technical manuals and pertinent directives should be studied for familiarization with the aircraft, its components, and the ground   handling   procedures   applicable   to   it,   before attempting to accomplish ground handling. b.      Ground   Handling   Safety   Practice.        Aircraft equipped    with    turboprop    engines    require    additional maintenance   safety   practices.      The   following   list   of safety   practices   should   be   observed   at   all   times   to prevent possible injury to personnel and/or damaged or destroyed aircraft: (1)    Keep  intake  air  ducts  free  of  loose  articles such as rags, tools, etc. (2)  Stay clear of exhaust outlet areas. (3)  During ground runup, make sure the brakes are firmly set. (4)  Keep area fore and aft of propellers clear of maintenance equipment. (5)        Do    not    operate    engines    with    control surfaces in the locked position. (6)      Do   not   attempt   towing   or   taxiing   of   the aircraft with control surfaces in the locked position. (7)  When high winds are present, do not unlock the control surfaces until prepared to operate them. (8)        Do    not    operate    engines    while    towing equipment is attached to the aircraft, or while the aircraft is tied down. (9)  Check the nose wheel position.  Unless it is in the centered position, avoid operating the engines at high power settings. (10)  Hold control surfaces in the neutral position when   the   engines   are   being   operated   at   high   power settings. (11)    When  moving  the  aircraft,  do  not  push  on propeller    deicing    boots.        Damage    to    the    heating elements may result. c.      Moving   Aircraft   on   Ground.      Aircraft   on   the ground shall be moved in accordance with the following: (1)  Taxiing.  Taxiing shall be in accordance with Chapter 8. 2-84