TM 1-1500-204-23-1 annually  or  when  there  is  a  possibility  of  mechanical damage.    If  any  damage  is  found,  it  must  be  repaired immediately. g. Static Grounding of Aircraft.    All  aircraft  parked in a hangar must be grounded (earthed) at all times. h. Static Grounding of Ground Support Equipment . Ground    support    equipment    in    a    hangar    must    be grounded  at  all  times  when  in  contact  with  the  aircraft being worked on. i. Emergency Evacuation of Aircraft from Hangar . A plan for the emergency evacuation of aircraft from a hangar  must  be  established  and  implemented  by  the maintenance  officer  using  the  expertise  of  the  aviation safety    officer    and    other    applicable    elements.    Care 2-7. Jacking  and  Hoisting.    General  instructions  for lacking   and   hoisting   are   explained   in   the   following paragraphs.      For   specific   instructions   on   a   particular aircraft, refer to the applicable maintenance manual. a. Jacking.    Use  the  following  procedures  for  in and out of hangar jacking: (1) Do   not   stand,   sit,   or   lie   inside   or   on aircraft during raising or lowering operations. (2) Ensure that all stress panels are installed on aircraft. (3) Disengage   aircraft   brakes   and   remove chocks. (4) Place  all  jacks  on  a  level  surface  so  that an  imaginary  line  drawn  through  any  2  feet  of  jack  will be parallel to fuselage or load to be jacked.  Jack only at specified jack points. (5) Position  auxiliary  supports  as  necessary to  adequately  prevent  accidental  injury  to  personnel  or damage to aircraft. NOTE Place   tail   stands   under   all   aircraft equipped  with  tricycle  landing  gear. Secure a ground-supported weight to tail    of    conventional    gear    aircraft. When    tail    wheel    is    to    remain    in contact   with   ground,   lock   it   after aircraft reaches desired height. Leave tail wheel free to roll fore and aft     during     jacking     and     lowering operations. (6) Operate all jacks simultaneously, both up and down, to prevent binding of aircraft struts.  Binding may be corrected by tapping strut with a rawhide mallet or kicking tire. (7) Ensure  that  there  is  sufficient  clearance above aircraft to complete desired operation. WARNING Aircraft on jacks shall be so labeled, and    access    restricted    to    prevent injury to personnel. CAUTION Unauthorized persons will not be in, on   or   under   aircraft   supported   by jacks.    Areas  shall  be  restricted  by proper warning signs and barriers to preclude entry into the area. NOTE The    use    of    auxiliary    supports    is recommended,  but  not  required,  as standard     jacks     are     designed     to withstand   all   vertical   loads.      When several  people  are  to  be  working  on the   aircraft,   auxiliary   supports   are highly recommended. (8) Do not jack aircraft when wind velocity is greater  than  maximum  amount  specified  in  applicable maintenance   manual.      When   applicable   maintenance manual   does   not   list   a   maximum   wind   velocity,   a velocity    of    15    miles    per    hour    will    be    considered maximum. 2-10            Change 3 must be taken to ensure the safe evacution of as many aircraft as possible in an emergency.