of the SUU-58/B dispenser, Mk 339 Mod 1 fuze, Kit Modification  Unit  KMU-428/B,  and  60  mines  (45 BLU-91/B  and  15  BLU-92/B).  The  fuze  initiation time is preset and is activated upon weapon release from  the  aircraft.  Fuze  time  settings  are  primary mode  (1.2  seconds)  and  option  mode  (4.0  seconds). The  KMU-428/B  adapts  the  mines  to  the  dispenser;  it also  provides  mine  activation/self-destruct  time selection. SUU-58/B Subsonic Free-Fall Dispenser The SUU-58/B consists of a cargo section with a nose fairing assembly attached, a tail cone assembly, and fuze  arming  wires  with  extractors.  There  are  two observation  windows-one  for  viewing  the  safe/arm indicator and the other to observe the fuze time-setting dials.  The  cargo  section  houses  the  BLU-91/B  and BLU-92/B  mines.  The  tactical  weapons  have  two yellow bands around the nose cone fairing. BLU-91/B and BLU-92/B Mines The  target  sensors  are  the  primary  difference between   the   two   mines.   The   BLU-91/B   uses   an armor-piercing warhead and a magnetometer type of sensor; the BLU-92/B has a fragment type of warhead with trip wires as the primary target sensor. PRACTICE  BOMBS LEARNING   OBJECTIVE:   ldentify   the different  types,  purpose,  and  use  of  practice bombs  to  include  subcaliber  and  full-scale practice bombs. Practice  bombs  are  used  to  simulate  the  same ballistic properties of service bombs. Practice bombs are  manufactured  as  either  solid,  cast-metal  bodies  or thin, sheet-metal containers. They can be filled with wet sand to obtain the necessary weight. Since practice bombs  contain  no  explosive  filler,  a  practice  bomb signal   cartridge   (smoke)   can   be   used   for   visual observation  of  weapon-target  impact. The primary purpose of practice bombs is safety when  training  new  or  inexperienced  pilots  and ground-handling  crews.  Other  advantages  of  practice bombs include their low cost and an increase in available target  locations. Although  not  classified  as  practice  bombs,  the  Mk 80  (series),  inert  filled,  LDGP  bombs  are  used  for full-scale  practice  bombing.  These  bombs  are physically the same as the Mk 80 (series) LDGP service bombs, but they do not contain explosive filler and are painted  blue.  These  bombs  provide  full-scale  training for assembly and loading crews and pilots. The general types of practice bombs are subcaliber or full-scale practice bombs. Subcaliber means that the practice bomb is much smaller in size and weight than the  service  bomb  it  simulates.  Full-scale  practice bombs are representative of service bombs in their size and  weight. SUBCALIBER  PRACTICE BOMBS There   are   two   types   of   subcaliber   practice bombs-the  Mk  76  Mod  5  and  BDU-48/B.  The  two types are used for practice and are quite different in design  and  appearance  from  each  other.  Each  type  is discussed  in  the  following  paragraphs. Mk 76 Mod 5 The Mk 76 Mod 5 is a 25-pound, solid, metal-cast, practice bomb (fig. 1-41). Its body is teardrop shaped and centrally bored to permit the insertion of a practice bomb signal cartridge. The afterbody, which covers the tail tube, is crimped to the bomb body and has welded-on conical tail fins. The bomb is designed with single lug suspension, using the Mk 14 suspension lug. The Mk 76 Mod 5 practice bomb is designed for impact firing only. It uses the Mk 1 firing pin assembly to initiate the practice bomb signal cartridge. The bomb signal and the firing pin assembly are held in the bomb by means of a cotter pin. The  bomb  is  painted  blue.  The  identification nomenclature is stenciled in white letters on the bomb body. Figure 1-41.—Mk 76 Mod 5 practice bomb. 1-45