made  of  nonslip,  nonmarking,  jet-fuel-resistant rubber.  The  steel  box  toe  is  constructed  of  cold- rolled  carbon  steel  to  provide  a  safety  margin through greater compression resistance. The boot is  designed  for  use  by  all  aircrew  members. Fitting The  boot  is  fitted  to  the  aircrew  member and  normally  corresponds  to  his  regular  shoe size. Maintenance The aircrew member is responsible for main- tenance  of  the  boot.  Maintenance  is  limited to  cleaning  and  polishing.  Polish  used  for everyday  care  of  shoes  is  acceptable.  There  are no authorized repairs, as the sole and heel should outwear  the  upper  boot.  Broken  or  worn  laces may  be  replaced. SV-2  SURVIVAL  VEST The  SV-2B  survival  vest  provides  maximum useful storage for survival equipment, consistent with  minimal  bulk  and  weight.  In  addition,  the survival  vest  provides  for  integration  of  a  life preserver,  anti-g  coveralls,  and  the  chest-mounted oxygen  regulator.  It  does  not  interfere  with  use of either the regular or integrated-type parachute harness. The SV-2B vest is the latest authorized configuration  for  this  series  of  survival  vest. Configuration The SV-2B survival vest is constructed basi- cally  of  nylon  cloth.  An  adjustable  harness, leg straps, and an entrance slide fastener provide a  means  of  fitting  and  securing  the  vest  to  the aircrew member. Elastic straps on the rear allow greater  comfort  and  mobility  of  the  wearer. Pockets  are  provided  for  stowage  of  survival  items (fig.  4-4).  When  required,  the  chest-mounted oxygen  regulator  is  located  inside  a  pocket  secured to  the  vest  by  means  of  hook  and  pile  tape. Fittings The basic SV-2B survival vest is designed to fit chest sizes from 40 to 48 inches. By changing the  elastic  straps  on  the  rear,  the  vest  may  be adapted  to  a  wider  size  range.  To  fit  an  SV-2B properly,  have  the  aircrew  member  wear  all  his normal   flight   gear,   including   the   MA-2   torso harness,  if  used.  Put  the  SV-2B  vest  on  as  if  it were  a  jacket.  Pass  the  leg  straps  through  the crotch and attach the snap hooks. Adjust the leg and shoulder straps so that they are snug and the bottom of the vest is just above the hips. Examine the  SV-2B  for  proper  fit.  If  it  is  too  loose,  the elastic straps must be shortened. If it is too tight, you  must  lengthen  the  elastic  straps.  The  pro- cedures  for  this  adjustment,  as  well  as  main- tenance,   calendar   inspections,   and   cleaning, are  covered  in-depth  in  the   Aircrew   Personal Protective   Equipment   Manual,   N A V A I R 13-1-6.7. ANTIEXPOSURE   ASSEMBLIES Antiexposure  assemblies  are  composed  of several  garments  that  protect  the  aircrew  member in  the  event  of  immersion.  Constant  wear assemblies   provide   additional   protection   from cold  weather.  The  constant  wear  assemblies consist of a waterproof outer garment worn over a  ventilation  liner  and/or  cold  weather  underwear. The  quick-donning  antiexposure  suit  is  carried in  the  aircraft,  and  donned  only  in  case  of emergency.  It  consists  of  a  waterproof  outer garment   equipped   with   permanently   attached boots  and  wrist  and  neck  seals.  An  inflatable  hood and  antiexposure  mittens  are  stowed  in  the pockets.  In  case  of  emergency,  the  assembly  is donned  over  the  regular  flight  clothing. Either   continuous-wear   or   quick-donning antiexposure  suits,  as  appropriate,  are  provided for flight personnel and passengers when there is a  significant  risk  of  crashing  in  the  water,  and when  any  of  the  following  conditions  prevail: 1.  The  water  temperature  is  50°F  or  below. 2. The outside air temperature (OAT) is 32°F (wind  chill  factor  corrected)  or  below. If the water temperature is between 50° and 60°F,   the   commanding   officer   of   the   unit concerned   considers   the   following   search   and rescue  (SAR)  factors: 1. The maximum probable rescue time. This should  be  a  function  of  mission  distance,  SAR equipment,  and  SAR  location. 2. The lowest temperatures that will occur in the  mission  area  during  the  time  period  of  the flight. 3.  Then  by  using  table  4-1,  he  determines whether antiexposure suits are required. 4-6