TM 55-1550-222-10 d Taxiing.     Whenever   possible,   taxiing   in   deep snow, light weight dry snow or slush should be avoided, particularly  in  colder  FAT  conditions.    If  it  is  necessary to  taxi  through  snow  or  slush,  do  not  set  the  parking brake when stopped.  If possible, do not park the aircraft in   snow   or   slush   deep   enough   to   reach   the   brake assemblies.    Chocks  or  sandbags  should  be  used  to prevent  the  aircraft  from  rolling  while  parked.    Before attempting   to   taxi,   activate   the   brake   deice   system, insuring that the bleed air valves are OPEN and that the condition levers are in HIGH IDLE.  An outside observer should   visually   check   wheel   rotation   to   ensure   brake assemblies have been deiced. e. Before Takeoff. 1. If icing conditions are expected, activate all anti- ice  systems  before  takeoff,  allowing  sufficient  time  for the equipment to become effective. 2. If   the   possibility   of   ice   accumulation   on   the horizontal stabilizer or elevator exists, takeoff will not be attempted. f Takeoff.    Takeoff  procedures  for  cold  weather operations are the same as for normal takeoff.  Taking off  with  temperature  at  or  below  freezing,  with  water, slush    or    snow    on    the    runway,    can    cause    ice    to accumulate  on  the  landing  gear  and  can  throw  ice  into the wheel well areas.  Such takeoffs shall be made with brake deice on and with the ice vanes extended. Before flight     into     icing     conditions,     the     pilot     and     copilot windshield  anti-ice  switches  should  be  set  at  NORMAL position. g. During Flight 1. After  takeoff  from  a  runway  covered  with  snow or slush, it may be advisable to leave brake deice ON to dislodge  ice  accumulated  from  the  spray  of  slush  or water.          Monitor     BRAKE     DEICE     annunciator     for automatic termination of system operation and then turn the  switch  OFF.    During  flight,  trim  tabs  and  controls should     also     be     exercised     periodically     to     prevent freezing.    Ensure  that  anti-icing  systems  are  activated before  entering  icing  conditions.    Do  not  activate  the surface deice system until ice has accumulated at least 0.5    INCH.        The    propeller    deice    system    operates effectively as an anti-ice system and it may be operated continuously in flight.  If propeller imbalance due to ice does   occur,   it   may   be   relieved   by   increasing   RPM briefly, then returning to desired setting.  Ice vanes must be extended when operating in visible moisture or when freedom  from  visible  moisture  cannot  be  assured,  at  + 5°C FAT or less.  Ice vanes are designed as an anti-ice system,  not  a  deice  system.  After  the  engine  air  inlet screens   are   blocked,   lowering   the   ice   vanes   will   not rectify the condition. 2. Stalling     airspeeds     should     be     expected     to increase   when   ice   has   accumulated   on   the   aircraft causing   distortion   of   the   wing   airfoil.      For   the   same reason,   stall   warning   devices   are   not   accurate   and should not be relied upon.  Keep a comfortable margin of airspeed above the normal stall airspeed.  Maintain a minimum     of     140     KNOTS     during     sustained     icing conditions  to  prevent  ice  accumulation  on  unprotected surfaces  of  the  wing.    In  the  event  of  windshield  icing, reduce airspeed to 226 KNOTS or below. h. Descent.  Use  normal  procedures  in  Section  II. Brake    icing    should    be    considered    if    moisture    was encountered   during   previous   ground   operations   or   in flight, in icing conditions with gear extended. i. Landing.    Landing  on  an  icy  runway  should  be attempted  only  when  absolutely  necessary  and  should not be attempted unless the wind is within 10°  of runway heading.  Application of brakes without skidding the tires on  ice  is  very  difficult,  due  to  the  sensitive  brakes.    In order  not  to  impair  pilot  visibility,  reverse  thrust  should be used with caution when landing on a runway covered with snow or standing water.  Use procedures in Section II for normal landing. j. Engine  Shutdown.    Use  normal  procedures  in Section II. k. Before  Leaving  the  Aircraft.    When  the  aircraft is  parked  outside  on  ice  or  in  a  fluctuating  freeze-thaw temperature  condition  the  following  procedures  should be   followed   in   addition-to   the   normal   procedures   in Section II.  After wheel chocks are in place, release the brakes  to  prevent  freezing.    Fill  fuel  tanks  to  minimize condensation, remove any accumulation of dirt and ice from the landing gear shock struts, and install protective covers to guard against possible collection of snow and ice. 8-53.    DESERT  OPERATION  AND  HOT  WEATHER OPERATION. Dust,  sand,  and  high  temperatures  encountered  during desert operation can sharply reduce the operational life of the aircraft and its equipment.  The 8-23