Downloaded from https://www.everyspec.com MIL-sTD-810D 19 July 1983 MSTHOD 520.0 TEMPERATURE, HUMIDITY, VIBRATION, ALTITUDE. ,SECTION I ti I-1 I-2 I-3 PURPOSE . . . . . . . . . . . . . . . . . . ...’ ENVIRONMENTAL EFFECTS . . . . . . . . . . . . ; . GUIDELINES FOR DETERMINING TEST . 520.0-1 520.0-1 1-4 I-5 PROCEDURES.ANDTEST CONDITIONS . . .... . . . . SPECIAL CONSIDERATIONS . . . . . . . . . . . . . REFERENCES . . . . . . . . . . . . . . . . . . . SECTION II . 520.0-2 . 520.0-23 520.0-24 11-1 II-2 II-3 II-4 APPARATUS . . . . . . . . . . . . . . . . . . . . PREPARATION FOR TEST PROCEDURES.....:::;: :::”:::::: INFORMATION TO BE RECORDED . . . . . . . . .. . . .’ 520.0-25 . 520.0-25 520.0-26 :
520.0-27, . SECTION I I-1 ~. The purpose of this test is to identify failures that temperature,,humidity, vibration, and altitude can induce in aircraft electronic equipment either individually or in any combination, during and flight operations. It may be used for other similar purpoees.t ~-.2 ~. Studieshave shown that thermal effects, vibration, moisture, humidity, and; in certain cases, altitude have the greatest effect on the life of aviation electronic equipment in the operational environment. These forcing functions collective y account fcr all but 12 percent of the environmentally induced failuree in the field.
(Of course other etresses such‘as eand and dust, salt fog, eto., are aleo significant and must be considered in a fully integrated test program.) Temperature, humidity, vibration, and altitude can interact to produce failures such as the following: a. Shattering of glass, vials,.snd optical equipment. b. Binding or slackening of moving parts. c. Separation of oonstituents. d. Chaige9 in electronic components. e. Electronic or mechanic~fai lureg due to rapid water or frost formation. f. Cracking of solid pellets or grains in explosives. ., s. Differential contraction or expansion of dissimilar materials. h. Deformation or fracture of components. i. Cracking of surface coatings. j.
Leakage of sealed compartments. METHOD 520.0 19 July 1983 520.0-1 .