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 2-2 to ensure correct interpretation of the lot number since there are currently two methods 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 month and year of manufacture determined from the CAD lot number. The resulting sum (date) is the shelf-life expiration date of the CAD in question. Example: Lot number/ date of manufacture 0579 + Shelf life in Years +6 used to derive lot numbers. Obtain the established Shelf-life expiration date 0585

Table 2-2.- Derivation of Lot Number

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.

Then, compare the two dates derived (shelf life 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 manufac-ture as determined from the lot number.