hot wheel assembly.   Upon ignition, misting fluid will accelerate  a  fire,  resulting  in  rapid  fire  growth  and excessive damage to the aircraft if it is not extinguished rapidly. WARNING A broken hydraulic line that causes misting of petroleum-based fluids around an overheated brake assembly can cause a potentially dangerous   and   destructive   fire. Intermittent application   of   water   fog   should   be   used   to extinguish   this   type   of   wheel   assembly   fire. Rapid cooling of a hot inflated aircraft tire/wheel     assembly     presents     an     explosion hazard.   Therefore, fire-fighting personnel must exercise   good   judgment   and   care   to   prevent injuries.  The  vaporized  products  of  hydraulic fluid decomposition will cause severe irritation to the eyes and respiratory tract. The  following  safety  information  pertains  to  all aspects of wheel assembly fire-fighting operations: ·  Rapid cooling may cause an explosive failure of a wheel assembly. ·  When water fog is used on a wheel assembly fire, an intermittent application of short bursts (5 to 10 seconds) every 30 seconds should be used. ·  The    effectiveness    of    Halon    1211    may    be severely     reduced     under     extremely     windy conditions  if  the  Halon  cannot  be  maintained on the fire source. ·  You must take protective measures to prevent hydraulic fluid from coming into contact with the eyes.   Seek medical attention immediately should the fluid come in contact with the eyes. ·  Positive-pressure,   self-contained   breathing apparatus    must    be    worn    in    fighting    fires associated with hydraulic systems. ·  Although   Halon   1211   may   extinguish hydraulic   fluid   fires,   reignition   may   occur because  this  agent  lacks  an  adequate  cooling effect. ·  In   a   fire,   F-14,   S-3,   and   C-5   aircraft   with beryllium   brakes   may   produce   irritating   or poisonous  gases.    These  gases  are  toxic,  and they are respiratory and eye irritants. ·  Because  heat  is  transferred  from  the  brake  to the wheel, agent application should be concentrated  on  the  brake  area.    The  primary objective is to prevent the fire from spreading upward  into  wheel  wells,  wing,  and  fuselage areas. Q12-16.   Where    should    you    direct    the    fire-fighting agent for an internal engine fire? Q12-17.   What  is  the  primary  agent  used  to  combat class C electrical fires? Q12-18.   What  is  the  greatest  hazard  associated  with overheated aircraft wheels and tires? Q12-19.   In  what  direction  should  you  approach  an aircraft  with  overheated  brakes  or  a  wheel fire? Q12-20.   What   are   the   four   materials   that   usually contribute to wheel assembly fires? SUMMARY In   this   chapter,   you   have   learned   about   aircraft crash, rescue, and fire-fighting techniques and procedures.     Fire  chemistry,  fire-fighting  agents,  and equipment used in dealing with naval aircraft were also covered. 12-21