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II-2.3 Composite mission test cycle

II-2.3.1 Test cycle. A test cycle consists of a single simulated conposite mission. A climatic set is a fixed nunber of test cycles (usually 6 to 15. as called out In the test plan) in which the tenperatis<e profile is offset by a fixed teeperature difference predetermined for each test cycle of ths set. A conplete Conposite Mission Combined Envlronnsnta Test conelsts of a пшЬег fueual ly five er worm) ot repeated climatic sets of test cycles.

11-2.3.2 Environment profile charts. For each of the controlled environments, prepare a chart plotting stimulus level versus time that best represents the conposite {nission. each chart should be based on a standard atmosphere and the time period for the conposite mission. These plots define the basic environment profiles that constitute a single test cycle and provide the patterns for controlling the environmental test apparatus. Methods for generating conposite mission environmental profiles are discussed in 1-2.3

11-2,3.3. Climatic offset table. Prepare a table or chart indicating the tenperature offsets applying to consecutive test cycles in a eliraatie set sf aboxit 6 to 15 eles (refer to figure 523.1-5). The offsets are chosen so that one climatic set wri.ll represent the predicted mixture of climates expected in operational missions. This process ia discussed in 1-3.4.1.

II-2.3.4 Combined environments control directions. Provide directions for adjusting each of the controlled environments throughout each conplete climatic

set of tsst cycles. Levels are obtained гош the ccnposite mission environment profile with the teriperature pattern for each cycle of the climatic set offset according to plan. These directions should not be finalized \jntl 1 test setip Is conpleted (see II-2.4).

II-2. ,4 Test settjp

II-2.4.1 (Зепёга!. Using instrvmented (but not necessarily operable) stores, assenble test items and environmsntal apparatus, with acconpanylng Irstrtasntaticn and controls, into the planned conflgLS>atlon, After eenspr calibrations: test each environment sepeately to check ability to reach test levels and rate-of-change requirements. With Individual environments checked out, run combined environments through a test cycle. Correct problems as necessary. The general accuracy and tolerance requirements of section 4 of thia standard snail be loi lowed where

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525.i-iS

and precautions to be taken by, operators wherever and whenever potential hazards exist. MIL-STD-882, Requirements for System Safety Program For Systems and Associated Subsystems and Equipment, shall be used as a guide for preparation of the Safety Program Plan. After approval by proper authority, the Safety Program Plan shall be

ig prspar.

II-2.4.2 Vibration checkout. Adjustment of the vibration sources to provide the best simulation of in-flight vibration response is an essential part of test SBtup. Vibration response simulation can involve the following types of error: spatial (relative distribution of levels among various locations and in different directions in or on the store), spectral (frequency spectrum shap>e at any location and direction in or on the store), and intensity (peak and rim values). An iterative process of eidjusting vibration stimulus variables (intensity, spectral envelope, iimited directivity/store positioning) and observing responses is conducted to minimize these errors. The goal is to find the stimulus adjustments for each test level which will optimize the correlation of test setup with corresponding captive-flight total vibration responses. (jptlmuBn values are noted and nade part of the Combined Environments Control Directions (II-2.3.4).

II-2.5 Operational checkout. Replace instrumented stores with one or more operable practice stores. Provide input power as required and use performance monitoring system at room environment and then, if required, during one or more mission test cycles of combined environments. Debug as necessary.

II-3 PROCEDURES

II-3.1 General Written step-by-step procedures shall be prepared as called out in the test plan.

11-3.2 Specific .procedures. The following operations should be considered as candidates for wsitten prccsdures:

a. Pre-test visual inspection and checkout.

b. Movmtlng and connection of test units in the chamber.

c. Calibration of instruments and apparatus.

d. Functional testing of the store(s).

e. Controlling the test cycle environments.

f. Post-test operations. II-4 INFORMATION TO Щ. P£CORDED

II-4.1 General. The test information to be recorded shall be Included in the test plan.

11 -4 .2 Exanples of infomation . to-be recorded

II-4.2.1 Test operation mfornation. For each test cycle, starting vnth number 1:

a. Starting and ending times.

b. Any deviations from specified time limits or environment patterns, or alternately, preservation of all continuous environment response records.

c. Operators on duty.

d. Pertinent comments.

II-4.2.2 Test item InfornBtion. For each item under test:

a. Test item identification (manufacturer, serial number, etc.).

b. Sp)ecific identification.

c. Results of pre-test, inspection and checkout.

d. Position occupied in test chamber, if more than one used.

e. Time *ien item installed in chamber and number of the test cycle first encountered.

g. Reason for removal.

h. Beeults of post-teat inspection nd checkout.

i. Disposition of item.

11-4.2.3 Special information for non-conforming item

a. Time non-conformance veas noted and nunber of test cycle in or after which it wets discovered.

b. Evidence indicating non-conformance.

c. Confirnation of failure if failure suspected and ex-planation of how it was confirmed.

d. Failure amalysis and diagnosis.

e. Disposition of item.

f. Faibjre report number.

g. Names of operators providing the above information. METHOD 523.1

523.1-20

*u.S. GOVERnHEriT FRINTIKG OTrlCt: 1985-70i-034/li219