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Forum: Reliability & Maintainability Questions and Answers

Topic: Reliability & Maintainability Questions and Answers

Topic Posted by: Reliability & Maintainability Forum ( )
Organization: System Reliability Center
Date Posted: Mon Aug 31 12:47:36 US/Eastern 1998

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Original Message:

Posted by: Pat Green ( )
Date posted: Wed Apr 28 10:07:40 US/Eastern 1999
The company I am employed by manufactures optical equipment which is fitted to Rotary as well as fixed wing cargo aircraft. We were contracted to perform a sand and dust test on the quartz lense of the specific LRU in question in accordance with MIL STD 810E method 510.3. The lense was sandblasted to a opaque condition and the result of the test was a fail for the LRU. Is there any method that one can equate this test to any type of operation or flying hours. Is this test a requirement for all airborne optical equipment.


Subject: Sand And Dust Testing
Reply Posted by: Bruce Dudley ( )
Organization: Reliability Analysis Center
Date Posted: Wed Apr 28 15:21:19 US/Eastern 1999
The sand and dust test from MIL-STD-810 is a representative test for all airborne equipment that is expected to operate in a world wide environment. There is no reason to expect that optic equipment exposed to outside conditions in operation should be exempt from this type of test. This test should represent the design life for the operating and non-operting conditions, usually worst case. Most military equipments are designed to last at least ten years. So, from a flying time perspective and a ten to one ratio of operating to non-operating time, I would expect that this test would be equivalent to 80,000 to 90,000 hours. Based on your test results, it sounds like some type of protection is necessary for the quartz lense.

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