Next, determine the installed-life expiration date  of  the  CAD  by  referring  to  the  NAVAIR 11-100-1  series  manual.  Obtain  the  installed-life figure (number of months or years) and add that figure to the date (month) the CAD’s hermetically sealed container was opened. The resulting sum (date) will be the installed-life expiration date for the CAD in question. Example: Date opened 0879 + Installed life in months +42 Installed-1ife  expiration  date 0283 Then, compare the two dates derived (shelf life and installed life). Whichever date occurs first is the CAD service-life expiration date. Example: Shelf  life 0585 Installed Life 0283 Service-life  expiration  date 0283 Since only the month and year are used in computing   service-life   dates,   the   date   the hermetically sealed container is opened and the expiration date must be computed to the last day of  the  month  involved.  If  the  date  the  sealed container was opened is not available, the installed life must be computed from the date of manufac- ture as determined from the lot number. MARKING  EXPIRATION  DATES Before installing a CAD in an aircraft system, both CAD service-life expiration dates (shelf life and installed life) must be known. The time limit that is exceeded first is the service-life expiration date of the CAD. This date must be entered into the  aircraft  logbook. Use  permanent  indelible  ink  for  marking CADS with container open dates and service-life expiration   dates.   DO not   scribe,   scratch,   or electroetch  these  dates,  as  damage  will  occur to  the  CAD’s  corrosion-resistant  surface.  The marking pen, NSN 7520-00-043-3408, is available from GSA supply and is recommended for this purpose. When  you  install  a  CAD  in  an  aircraft system, a log entry must be made on OPNAV Form   4790/26A   as   directed   by   OPNAV- INST 4790.2. When a CAD’s hermetically sealed container  is  opened,  the  container  open  date and   the   service-life   expiration   date   (month and   year)   must   be   marked   with   indelible ink  on  the  container  and  on  each  CAD  in  the container. SERVICE-LIFE  EXTENSION Contingency service-life extensions for the CADS listed in the NAVAIR 11-100-1, not to ex- ceed  30  days,  may  be  granted  by  the  com- manding  officer  or  his  authorized  representative. These extensions may be applied to a specific CAD  on  a  one-time-only  basis  when  replace- ments  are  not  available  and  failure  to  extend the   service   life   would   disrupt   flight   opera- tions.   The   contingency   authority   is   granted on  the  condition  that  Naval  Ordnance  Station (NAVORDSTA),  Indian  Head,  Maryland;  NAV- AIRSYSCOM,  Washington,  D.C.;  and  SPCC, Mechanicsburg,  Pennsylvania  be  immediately notified by message or speed letter when such authority is exercised. When  the  situation  warrants,  an  additional service-life  extension  beyond  the  30-day  con- tingency extension may be requested by message from the NAVORDSTA. All extensions beyond 30 days must be approved by the NAVORDSTA or NAVAIRSYSCOM. All approved additional service-life  extensions  will  be  transmitted  by message to the activity making the request. When a service-life extension is granted, an entry must be made in the aircraft logbook. When an aircraft is  transferred  with  a  service-life  extension  in effect,  the  gaining  activity  must  be  notified,  and no  new  contingency  service-life  extensions  may be granted by the commanding officer of the gain- ing  activity. SERVICE-LIFE  CHANGE The  permanent  service  life  of  a  CAD may   be   changed   only   by   a   rapid   action change   (RAC),   interim   rapid   action   change (IRAC), or formal change to NAVAIR 11-100-1 as  directed  by  Commander,  Naval  Air  Sys- tems   Command   (COMNAVAIRSYSCOM), Washington,  D.C.  If  the  change  affects  those items  installed  in  an  aircraft,  the  change will  be  recorded  in  the  aircraft’s  logbook. 2-25