Failure Criteria - In addition to the requirements of MIL-STD-781, the
following requirements shall be used to determine when a failure has occurred during the test:
(1) Whenever performance characteristics fall below the acceptance
requirement (220.127.116.11) at least one failure has occurred. If subse-
quent analysis reveals that several parts have deteriorated, each
shall be counted a failure, unless one caused the other parts to fail.
Preventive Maintenance - During the period of the tests no preventive
maintenance measures are required.
Special Tests - Special tests shall be conducted on a quantity of equip-
ments for the purpose of checking the effect of any design or material change on the per-
formance of the equipment and to assure adequate quality control. The equipment selected
for special tests may be selected from equipments previously subjected to the sampling or
reliability assurance tests.
Special Test Schedule - Selection of equipments for special tests shall be
made as follows:
(1) On an early equipment after an engineering or material change.
(2) Whenever failure reports or other information indicate additional
tests are required. (This will be determined by the procuring
Scope of Tests - Special tests shall consist of such tests as approved by
the procuring activity. Test procedures previously approved for the preproduction tests
shall be used where applicable. When not applicable, the contractor shall prepare a test
procedure and submit It to the procuring activity for approval prior to conducting the tests.
Equipment Failure - Should a failure occur during either the sampling,
reliability y assurance or special tests, the following action shall be taken:
(1) Determine the cause of failure.
(2) Determine if the failure is an isolated case or design defect.
(3) Submit to the procuring activity for approval, proposed corrective
action intended to reduce the possibility of the same failure(s)
occurring in future tests.
(4) Where practical, include a test in the individual test to check all
equipment for this requirement until reasonable assurance is ob-
tained that the defect has been satisfactorily corrected.
Life Test - The contractor shall furnish all samples and shall be respon-
sible for accomplishing the life test. The test shall be of 300-hours duration and shall be
conducted on equipments that have passed the individual test. The life test shall be performed