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|  MIL-D-81347C(AS)
Test Repoting - The contractor shall submit to the procuring
4.4.2.5
activity a report of the demonstration. This is report shall include all pertinent data and observations,
major problem areas and recommendations for corrective action as required.
Reliability Assurance Tests - Reliability Assurance Tests shall
4.4.3
be conducted in accordance with MIL-STD-781 for both the Qualification phase and the Production
Acceptance phase. The Qualification phase shall include a Life Test of the Keyset and Panel mono-
function switches. Classification of failures shall be in accordance with MIL-STD-781 and AR-34.
General Requirements
4.4.3.1
4.4.3.1.1
Test Details - Test level E of MIL-STD-781 shall be used
except that the lower temperature limit shall be -25C 2C and the maximum vibration for Logic Units
1, 2 and 3 shall be a maximum of 2g l0%. The Logic Unit 4 vibration shall be at any nonresonant
frequency between 20 and 60 Hz and at a level in accordance with MIL-E-5400 Curve I between 20 and
32 Hz or at 2g between 32 and 60 Hz. No vibration shall be applied to the keysets and panels and
measurements on these units shall be taken at room temperature only. Test chambers for keysets and
panels shall be capable of maintaining the ambient and forced air temperatures at the specified test
level temperatures 3C during the test. The rate of the temperature change of the thermal medium in
both the heating and cooling cycles shall average not less than 2C/minute. The length of the heat por-
tion of the cycle, performance characteristics to be measured, special failure criteria etc. , shall be
part of the test procedures to be submitted by the contractor and approved by the Procuring Activity
prior to commencement of testing,
Preventive Maintenance - No preventive maintenance shall be
4.4.3.1.2
allowed during any phase of the reliability testing except when approved in advance by the procuring
activity. An unapproved preventive maintenance action shall be considered prima facie evidence of a
failure.
Qualification Phase
4.4.3.2
4.4.3.2.1
Reliability Demonstration
Logic Units 1, 2, 3, and 4 - A group of four Logic Units com-
4.4.3.2.1.1
prised of one Logic Unit 1, one Logic Unit 2, one Logic Unit 3 and one Logic Unit 4 shall be tested for
a fixed length test operating time of 1436 hours each. The Accept criterion shall be 12 or fewer
failures for the group: the Reject criterion shall be 13 or more failures.
Keyset and Panel Components - The following Keyset and Panel
4.4.3.2.1.2
components shall undergo demonstration testing for a cumulative test time of 3.9 times their specified
MTBF's:
(1) 6 Volt Regulated Power Supply - Specified MTBF of
1000 hours.
(2) Blower - Specified MTBF of 2000 hours.
(3) Lamp Driver - Specified MTBF of 5000 hours.
(4) Binary Decoder - Specified MTBF of 4000 hours.
(5) Projection Readout - Specified MTBF of 3000 hours.
The Accept criterion for the 6 Volt Regulated Power Supply and
Blower shall be six or fewer failures: the Reject criterion shall be seven or more failures. Accept-
Reject criteria shall not apply to the lamp drivers, binary decoders and projection readouts. The
tests of these components shall be performed for the purpose of obtaining reliability and quality infor-
mation only.
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