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|  MIL-D-70789A (AR)
alternative(s) provides equivalent assurance, the provisions of
this specification shall apply. All approved alternative
provisions shall be specifically incorporated into the
contractor's quality program plan or detailed inspection system,
as applicable.
4.7.2
Failures.
All failures shall be reported and
analyzed. A summary of all failures shall be provided to the
government as required in the contract. In addition to paragraph
4.4 the following shall apply to failures occurring during ESS.
If no failures occur that require removal of the DRU from the
temperature chamber, at the conclusion of the temperature cycling
sequence, the standard deviation about the mean of the azimuth,
pitch and roll data (20 recorded data each) shall be calculated.
No datum shall be excluded, and a single calculation shall be
made for each attitude, combining both high and low temperature
data. If the standard deviation for azimuth exceeds 1.0 roil, or
the standard deviation for either pitch or roll exceeds 0.5 roil,
the unit shall be rejected and, after adjustment/repair,
subjected to the entire random vibration and temperature cycling
sequence.
If a failure(s) requires the DRU to be removed from the
temperature chamber for adjustment, replacement or repair of a
part or assembly, at the conclusion of the temperature cycling
sequence, the standard deviation about the mean of the azimuth,
pitch, and roll data shall be calculated using only the data
recorded after the DRU is returned to the temperature chamber (a
minimum of 6 recorded data each). Data recorded before
removal(s) shall be excluded, but no datum shall be excluded from
the calculations after the DRU is returned to the temperature
chamber for the final temperature cycling sequence. A single
calculation shall be made for each attitude, combining both high
and low temperature data. If the calculated value of azimuth is
1.0 mil or less, and the calculated values for pitch and roll are
0.5 mil or less, the unit shall have passed the test. If any of
these values are exceeded, the contractor shall be permitted at
his discretion to perform additional cycles to increase the total
sample size up to a total of 20 recorded data each. At the
conclusion of each additional cycle, the standard deviation of
the mean of each attitude shall be recalculated, conibining both
high and low temperature data and excluding no datum of any
attitude recorded beginning when the DRU was returned to the
temperature chamber. If the recalculated value of the azimuth is
1.0 mil or less, and the recalculated values for pitch and roll
are 0.5 mil or less, the unit shall have passed the test. If any,
of these values are exceeded, the contractor shall be permitted
to perform additional cycles to attempt to bring the results of
the calculations within the stated specifications. If after
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