A  line  will  be  drawn  through  the  service- life expiration date shown and the new computed expiration   date   entered   citing   the   authority for  the  change;  for  example,  message  num- ber,  rapid  action  change  number,  or  change number.  Each  new  expiration  date  will  super- sede  the  previous  date.  The  latest  expiration date  entered  in  the  aircraft  logbook  will always be the final date the CAD may remain installed in the aircraft. When  a  contingency  service-life  extension  has been  authorized  for  a  specific  CAD,  the  new computed service-life expiration date (month and year) will be added to the original aircraft logbook entry  for  that  CAD.  When  an  additional  service- life  extension  has  been  granted  for  a  specific CAD, the new service-life expiration date (month and year) will be added to the original aircraft logbook entry. CAD  MAINTENANCE  POLICY Learning Objective: Identify CAD main- tenance   policy   to   include   SMDC   and FCDC  maintenance  and  inspection  re- quirements and safety precautions. CAD   maintenance   policy   prohibits   un- authorized  maintenance  or  adjustment  to  a  CAD at   any   of   the   three   levels   of   maintenance: organizational, intermediate, or depot. Author- ized maintenance actions are limited to removal, inspection, and replacement unless specifically detailed  in  the  aircraft  MIM  or  by  a  technical directive. CADS  and  items  of  equipment  in  ejection systems are for one-time use only. They are never to be refurbished or used again after firing. This is equally true of functional equipment, rigid lines, plumbing  lines,  and  hoses.  Ejection  seats  and escape system components that have been used in  an  ejection  or  fired,  regardless  of  apparent condition, are prohibited from reuse and must be disposed of as directed by OPNAVINST 4790.2, OPNAVINST 3750.6, and the applicable CAD and rocket manual. Because of the extreme stress and strain to the ejection  seats  and  escape  system  components during ejection, they cannot be reused. This stress could   reduce   the   structural   or   mechanical 2-26 reliability  y  of  these  items.  In  the  case  of  an inadvertent  firing  of  a  cartridge  or  CAD,  all contaminated  ballistic  lines  and  devices  must  be replaced because of the corrosive nature of the explosive. The  service  life  of  wire-braid,  teflon-lined hoses installed in ballistic applications is the same as that of the aircraft in which it is installed, unless it is used. A hose is considered to be used if the device  to  which  it  is  attached  is  fired,  either intentionally or accidentally. If this occurs, the hose and related fittings must be replaced. Before you install a hose or fitting (line, T, elbow, etc.), make sure that it is not contaminated by hydraulic fluid, oil, or a similar type of contaminant. All hoses in the escape system must be inspected for accidental damage at every phased inspection, upon seat removal, after removal of any part of the escape system, and for disconnection of any hose. When CADs are not installed in an aircraft, the  inlet  and  outlet  ports  must  be  sealed  with protective  closures  to  prevent  the  entrance  of moisture   and   foreign   matter.   For   shipping purposes,  the  safety  pins  and  protective  closures provided  with  the  replacement  CAD  must  be returned with the replaced CAD to ensure it is in a  safe  condition  during  handling  and  storage. During ejection system maintenance actions, all disconnected  CADs  and  associated  ballistic  lines must  be  protected  with  flexible  plastic  plugs  that conform  to  MIL-C-5501/l0A  and  flexible  plastic caps  that  conform  to  MIL-C-5501/l1.  NAV- AIR  11-100-1.1  provides  information  relating  to these caps and plugs. SMDC  AND  FCDC  MAINTENANCE AND  INSPECTION  REQUIREMENTS The major components of an SMDC assembly are  the  stainless  steel  tubing  (SST),  outer and   inner   ferrules,   a   silicone   rubber   seal, a 0.004-inch thick SST booster cup, an explosive booster  charge,  and  a  sheathed  explosive detonating  cord.  A  sectioned  drawing  of  a standard  SMDC/FCDC  tip  assembly  is  shown in  figure  2-19.  The  SMDC  assemblies  used in  the  canopy  and  hatch  severance  system are  similar  in  design  and  construction  except for  the  length  and  bend  configuration  of the  stainless  steel  tubing  and  silver  sheathed explosive detonating cord.