Downloaded from https://www.everyspec.com ADS-79D-HDBK CONTENTS PARAGRAPH PAGE D.4 SPECIFIC GUIDANCE ......................................................................................77 D.4.1 Condition indicator (CI) and health indicator (HI) behavior ...............................77 D.4.2 CI and HI Confidence ..........................................................................................78 D.4.2.1 False positive rate ................................................................................................78 D.4.2.2 False negative rate ...............................................................................................79 D.4.2.3 Fault isolation rate ...............................................................................................79 D.4.2.4 Software development .........................................................................................79 D.4.2.5 Recommended maintenance actions ....................................................................79 D.4.2.6 Predictability ........................................................................................................79 D.4.2.7 Time horizon guidance ........................................................................................79 D.4.3 CI and HI Confidence Level Requirements ........................................................79 D.4.3.1 Level 1.
Verified and Validated CIs/ HIs ............................................................79 D.4.3.2 Level 2. Mature CIs/ HIs .....................................................................................80 D.4.3.3 Level 3. Established CIs /HIs ..............................................................................80 D.4.3.4 Level 4. Developmental CIs/ HIs ........................................................................80 D.4.3.5 Level 5. Nascent CIs/ HIs ....................................................................................80 D.4.3.6 Level 6.
Retired CIs/ HIs .....................................................................................80 D.4.4 Health indicator (HI) usage .................................................................................80 D.5 APPROACH:
CI/HI DEVELOPMENT FOR LEGACY AIRCRAFT ..............84 D.5.1 Initial situation .....................................................................................................84 D.5.2 CI development process ......................................................................................84 D.5.2.1 Understand the failure mode ...............................................................................85 D.5.2.2 Determine the best means of measurement .........................................................86 D.5.2.3 Determine the existing system capabilities .........................................................85 D.5.2.4 Identify candidate feature extraction/CI algorithms ............................................87 D.5.2.5 Obtain data to train and evaluate the CI ..............................................................88 D.5.2.6 Code the algorithms and test performance ..........................................................89 D.6 APPROACH:
CI/HI DEVELOPMENT FOR NEW DEVELOPMENTAL AIRCRAFT ..............................................................90 D.6.1 Initial situation .....................................................................................................90 D.6.2 CI development process ......................................................................................90 D.6.2.1 Understand the failure mode ...............................................................................90 D.6.2.2 Determine the best means of measurement .........................................................91 D.6.2.3 Determine the design system capabilities ............................................................91 D.6.2.4 Identify candidate feature extraction/CI algorithms ............................................91 D.6.2.5 Obtain data to train and evaluate the CI ..............................................................91 D.6.2.6 Code the algorithms and test performance ..........................................................91 D.7 IN-SERVICE APPROACH:
CI CREATION PROCESS FOR APACHE AFT HANGER BEARINGS ......................................................................92 D.7.1 Design Goals and Evaluation Criteria .................................................................92 D.7.2 Fault Frequency Calculation ................................................................................93 D.7.3 MSPU Bearing Energy CI Creation ....................................................................95 D.7.4 MSPU High Frequency Energy CI Creation .......................................................95 D.7.5 Effectiveness ........................................................................................................95 D.7.6 Normal and Faulted CI levels ..............................................................................96 vii