TM 1-1510-223-10 Section V.  ADVERSE ENVIRONMENTAL CONDITIONS 8-47.  INTRODUCTION. The purpose of this section is to inform the pilot of the  special  precautions  and  procedures  to  be  followed during   the   various   weather   conditions   that   may   be encountered in flight This section is primarily narrative, only   those   checklists   that   cover   specific   procedures characteristic  of  weather  operations  are  included.    The checklist in Section II provides for adverse environmental operations. 8-48.  COLD WEATHER OPERATIONS. To  ensure  adequate  bleed  air  pressure  to the    deice    boots,    do    not    simultaneously actuate    the    surface    and    antenna    deice systems in the manual mode. Operation   of   the   surface   deice   system   in ambient   temperatures   below   -40   °   C   can cause    permanent    damage    to    the    deice boots. NOTE Under    conditions    where    one    bleed    air source   is   inoperative,   sufficient   bleed   air pressure for deice boot inflation may not be available.      Prior   to   deice   boot   inflation, check the regulated bleed air pressure gage for   a   minimum   of   16   PSI.      If   insufficient pressure exists, increasing engine N, and/or decreasing    aircraft    altitude    will    increase bleed air pressure. Operational  difficulties  mav  be  encountered  during extremely  cold  weather,  unless  proper  steps  are  taken prior to, or immediately after flight All personnel should understand    and    be    fully    aware    of    the    necessary procedures and precautions involved. a. Preparation  For  Flight.    Accumulations  of snow,  ice,  or  frost  on  aircraft  surfaces  will  adversely affect   takeoff   distance,   climb   performance,   and   stall speed   to   a   dangerous   degree.      Such   accumulations must be removed before flight In addition to the normal exterior  checks,  following  the  removal  of  ice,  snow,  or frost,  inspect  wing  and  empennage  surfaces  to  verify that  these  remain  sufficiently  cleared.    Also,  move  all control  surfaces  to  confirm  full  freedom  of  movement Ensure that tires are not frozen to wheel chocks or to the ground.  Use ground heaters, anti-ice solution, or brake deice   to   free   frozen   tires.      When   heat   is   applied   to release tires, the temperature should not exceed 71°  C (160°  F).    Refer  Chapter  2  for  anti-icing,  deicing,  and defrosting treatment. b. Engine Starting.  When starting engines on ramps  covered  with  ice,  PROP  levers  should  be  in  the FEATHER position to prevent the tires from sliding. c. Warm-up and Ground Test. Warm-up procedures and ground test are the same as those outlined in Section II. 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, ensure  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  to  the 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 8-30