ADS-79D-HDBK Downloaded from https://www.everyspec.com functional capability, data integrity, and safety of the newly constructed test stand/platform, as designed and built by the test facility. J.4.3 Step 3: Testing. The testing phase proceeds from specimen setup through experiment conduct to test report documentation. Ideally, the seeded fault laboratory experiment should either be positively correlated/scaled to on-aircraft values in the report or be followed by confirmation with on-aircraft testing of the implemented CBM approach derived from the laboratory experiment.
This step, referred to as on-aircraft testing, allows for a proposed CBM approach demonstrated in the laboratory to be monitored in the actual operating environment before introducing the application on field aircraft. a. Specimen setup – All minor modifications and servicing to the specimen should be made before installation in the fixture to minimize interruption of the test run. For example, the part should be cleaned prior to installing in the jig to allow for better test observation. b.
(Bench) specimen test run / collect data – On completion of all pre-test analysis, review and setup, the seeded test specimen should be stressed within applicable aircraft flight load survey results until the appropriate level of fault degradation and related monitoring is reached. If available in the test fixture design, the automated monitoring equipment should be used to maintain a continuous observation of the test specimen condition. However, it may also be acceptable to periodically stop the test to perform visual inspection. c.
(Bench) test report preparation – Upon completion of all specimen test runs, a comprehensive test report should be created to document all observed events, findings, and analytic results of the laboratory experiment. The findings should include summary of conclusions concerning the detectability of the fault, as well as the general impression of the condition and health indicator‘s ability to reliably detect and track the phenomenon within a specified timeframe. The specified timeframe should be discussed relative to the anticipated download intervals from the field aircraft.
The report should also document the original condition of the test specimen, test fixture, all pre-test analysis, and Tear Down results. The comprehensive test report should be written using Data Item Description DI-NDTI-80809B as a guide. During the laboratory bench testing phase, considerations should be given to conducting on-aircraft testing of the proposed CBM technique. These considerations can be weighed against the robustness of testing results and the applicability of the results to the aircraft.
The purpose of on-aircraft testing is to confirm the implemented technique is sufficiently robust to detect the fault and monitor fault progression in the noise environment of normal aircraft operation. Following a review of bench test results and the decision to validate the CBM hardware on aircraft, an AWR should be developed to allow limited testing of the CBM hardware on a specific number of aircraft. The on-aircraft testing is essentially a limited repeat of the bench testing with a seeded specimen placed in a test aircraft for evaluation using a combination of legacy maintenance and CBM prior to fleetwide implementation.
Data is again collected and evaluated with a test report documenting the results of the experiment. 181