Downloaded from https://www.everyspec.com MIL-STD-81OD ~ 19 JUIY ‘1983 I I-3 This test method should be applied only at the end of the tailoring,process described in section 4 of this standard. ,. , I :... ..a. This method is primarily intended for.electronic . equipment mounted inside an aircraft. The procedures of’this method”can be used for engineering development, fo,rsupport of,flight testing; and for, . qualification. ... .,.. ...’., ,. ,,:., b. ~. This does not apply to electronic”equipment transported as cargo in an aircraft. ,, ,. 0. Procedure 1.is intended to be used before final.equipment designs.are.fixed. ,, d. Xes t v~.
The test variables are temperature, humidity., vibration, altitude, cooling airflow, electrical :trease:;,. RShS. Of change,.-i test duration. ,.. . I-3;1 _ChQiceof test Drocedurea ,. “1-s..1 .1 veloDment test..‘The“engineering deVelODUIenttest is used.to find defects in a new desimwhile it is still in the de~elopment stage. The test is failure-orierited,;eaning that the tester. should hope to uncover as many defects as possible. A combined environment test is good for this purpose, since it does not require the teeter first to predict which stress states a~e most critical ,?ndthen to tailor the test to ..: emphasize those states. This test is generally accelerated by eliminating ... .
benign conditions or by using higher stresses than the item is likely?to encounter in the field. 1-3.1.2 ure II -. Kht or onerat~r t test. ,Thi.stest is performed in preparation for, or during,.flight or operational testing. Its purpose is to minimize delays in the flight testing progrsm due to environ-. mental factora. This test is not accelerated; the ,damageaccumulation in the . test is’no faster than in operational or in-flight testing. ,Therefore, development hardware can be interchanged between laboratory and flight or operational testing.
This meana that when unusual problems develop in flight or operational testing, the equipment.system can be brought into the laboratory to help.identify any environmental contribution to the observed problem. I-3.1:3 ~cation test. The qualification test is a formal test intended to demonstrate compliance with contract requirements. Generally, qualification testing is an accelerated test that emphasizes the .? most significantenviron- mental stress conditions. The use of Procedure .1of this test method for.qualification is not recommended..
The qualification test shall.include the maximum amplitude of each stress and an~ unique combination of ptress types that were found to be important in the engineering development :. testing of the test item. ... METHOD 520.0 19 July 1983 520.0-2