particular defect class For example if the sampling
table indicates acceptance for the Major-A defect
class, but requires an additional sample to reach
and accept or reject decision for Major-B defects,
Major-A defectives so observed on the second sam-
ple will not contribute to lot rejection of the
headed Major-A and Major-B. The numbers under
Major-A defect class When a rejection number is
the column headed AC refer to the maximum allow-
reached in a second stage sample. inspection will be
able number of defective item(s) in the sample that
discontinued
are permissible for acceptance. Conversely. the
(3) Inspection method Perform technical inspec-
numbers under the columns headed RE refer to the
tion of the selected samples Functional or per-
minimum number of defective item(s) in the sam-
formance tests should he avoided unless there are
ple required to cause rejection of the lot.
significant indications that components of the items
(b) Double sampling plan. A double sampling
have deteriorated to a degree that operational prob-
plan, corresponding to the appropriate lot size is
lems will exist
used if a successive stage cumulative acceptance
c Defect Classification Refer to Appendix B and
and rejection numbers are indicated The same
C for listings of defects and their classifications De-
sample size is used to determine the acceptance for
fects should be classified as critical (when critical
both Major-A and Major-B defectives The inter-
pretation of the columns headed by AC and RE is
defects are considered), Major-A, Major-B or Minor,
the same as that described for the single sampling
even if they are not considered to belong fully in
these classes at the time of the inspection, but can
plan in (a) above If at the first sampling stage, the
reasonably be expected to be in these classes prior
number of defective items found IS between the two
to the next scheduled inspection period When in-
numbers indicated in the column headed by AC and
spection or testing of an item reveals a critical de-
RE, an additional sample must be selected to arrive
fect, the lot represented will be rejected Defects
at an accept or reject decision for only one particular
noted during the inspection and classified as minor
defect class. If an additional sample is required
will not be cause for rejection of the lot
for only one particular defect class, the inspection
12. Other Instructions. a Rejected Lots Units
of the second sample will be restricted to only that
4
