TM 55-1510-220-10 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. Slowly  adjust  the  valve  position  so  that pressure increases at a rate not to exceed 200 PSIG per minute. 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- :32). NOTE To    compensate    for    loss    of    aircraft cylinder pressure as the oxygen cools to ambient  temperature  after  recharging, the cylinder should be charged initially to approximately 10% over  prescribed pressure.      Experience   will   determine what initial  pressure  should be used  to compensate for the subsequent pressure loss  upon  cooling.    A  small  top-off  will create little heat.  A complete recharge will   create   substantial   heating.      The final stabilized cylinder pressure should be   adjusted   for   ambient   temperature per figure 2-32. 7. Disconnect   oxygen   hose   from   oxygen servicing unit and filler valve. 8. Install   protective   cap   on   oxygen   filler valve. 9. Install oxygen access door. 2-102.  GROUND HANDLING. Ground   handling   covers   all   the   essential   information concerning movement and handling of the aircraft while on the ground.        The    following    paragraphs    give    in    detail,    the instructions  and  precautions  necessary  to  accomplish  ground handling   functions.      Parking,   covers,   ground   handling   and towing equipment are shown in figure 2-33. 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   he 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  surface  in the locked position. (6) Do not attempt towing or taxing of the aircraft with control surfaces until prepared to operate them. (7) When high winds are present, do not unlock the control surface 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. Change 2   2-88