TM 55-1510-220-10 Section V.  ADVERSE ENVIRONMENTAL CONDITIONS 8-67.  INTRODUCTION. The  purpose  of  this  part  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   part   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. 8-68.  COLD WEATHER OPERATIONS. CAUTION Operation  of  the  surface  de-ice  system  in ambient    temperatures    below    -40°C    can cause   permanent   damage   to   the   de-ice boots. Operational   difficulties   may   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 speeds 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.    Assure that tires are not frozen to wheel chocks or to the ground. Use  ground  heaters,  anti-ice  solution,  or  brake  de-ice,  to free  frozen  tires.    When  heat  is  applied  to  release  tires, the temperature should not exceed 71°C  (160°F).    Refer to    Chapter    2    for    anti-icing,    deicing,    and    defrosting treatment. b. Engine Starting.  When starting engines on ramps covered    with    ice,    propeller    levers    should    be    in    the FEATHER  position  to  prevent  the  tires  from  sliding.    To prevent exceeding torque limits when advancing CONDITION   levers   to   HIGH   IDLE   during   the   starting procedure,   place   the   power   lever   in   BETA   and   the propeller    lever    in    HIGH    RPM    before    advancing    the condition lever to HI IDLE. 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  de-ice  system,  insuring  that  the bleed  air  valves  are  OPEN  and  that  the  condition  levers are in HI IDLE.  An outside observer should visually check wheel   rotation   to   insure   brake   assemblies   have   been deiced.    The  condition  levers  may  be  returned  to  LOW IDLE as soon as the brakes are free of ice. 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.      If   icing conditions are expected, activate all anti-ice systems  before  takeoff,  allowing  sufficient time for the equipment to become effective. f. Takeoff.      Takeoff   procedures   for   cold   weather operations are the same as for normal takeoff.  Taking off with  temperatures  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 de-ice on and    with    the    ice    vanes    extended    to    preclude    the possibility of ice build-up on engine air inlets.  Monitor oil temperatures   to   insure   operation   within   limits.      Before flight  into  icing  conditions,  the  pilot  and  copilot  WSHLD ANTI-ICE switches should be set at NORMAL position. g. During Flight. (1)    Brake  de-ice.    After  takeoff  from  a  runway covered   with   snow   or   slush,   it   may   be advisable   to   leave   brake   de-ice   ON   to dislodge ice 8-29