Expiration Dates

To determine service-life expiration dates, both the shelf life and installed life must be computed. First, compute the shelf life of the CAD by using its lot number to determine the month and year of manufacture. Refer to table 1-1 to ensure correct interpretation of the lot number since there are currently two methods used to derive lot numbers. Obtain the established shelf life (number of months and years) for the individual CAD from the NAVAIR 11-100-1 series manual. Add this figure (shelf life) to the

Table 1-1.-Derivation of Lot Number

month and year of manufacture determined from (date) will be the installed-life expiration date for the CAD lot number. The resulting sum (date) is the CAD in question. the shelf-life expiration date of the CAD in question. Example:

_Example:

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 CADs hermetically sealed container was opened. The resulting sum (date) will be the installed-life expiration date for the CAD in question.

Then, compare the two dates derived (shelflife and installed-life). Whichever date occurs first is the CAD service-life expiration date.

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 manufacture 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) should be computed. The time limit that is exceeded first will be the service-life expiration date of the CAD. The service-life expiration date must be entered in the aircraft logbook.

Use permanent ink for marking CADs with container opened dates and service-life expiration dates. Do not scribe, scratch, or eletroetch these dates, as damage will occur to the CAD's corrosion resistance 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 OPNAVINST 4790.2 (series). When a CAD's hermetically sealed container is opened, the container opened 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.