SAE ARP5107B

1 SCOPE
  1.1 Purpose
  1.2 Summary of Revision
  1.3 Field of Application
2 REFERENCES
  2.1 Applicable Documents
      2.1.1 FAA Publications
      2.1.2 EASA Publications
  2.2 Acronyms and Symbols
3 APPLICABILITY
4 HISTORICAL PERSPECTIVE
5 HISTORY OF INTEGRITY GUIDELINES
6 GENERAL ANALYSIS APPROACH
  6.1 FADEC System Configuration
  6.2 Repair Categories: Immediate, Short, and Long Time
  6.3 Classification of FADEC Fault Types
      6.3.1 No Dispatch (ND) Type Faults
      6.3.2 Short Time (ST) Type Faults
      6.3.3 Long Time (LT) Type Faults
      6.3.4 Combinations of Faults and Uncovered (UC) Faults
      6.3.5 Aircraft Related Information
  6.4 Recommendations an Items Considered Part of the FADEC
      System
7 CALCULATION APPROACHES: SINGLE ENGINE ANALYSIS
  7.1 A Simple Time-Averaging Approach
      7.1.1 LOTC Rate for Full-up Electronics
      7.1.2 Average LOTC Rate for Short Time (ST) Faults
      7.1.3 Average LOTC Rate for Long Time (LT) Faults
      7.1.4 Calculations of the Average LOTC Rate Using the TWA
            Approach
      7.1.5 An Example Calculation
  7.2 Markov Model Approach
      7.2.1 Open Loop Markov Models
      7.2.2 Closed Loop Markov Model Approach
      7.2.3 Examples of Single Fault States
      7.2.4 Acceptability (and Accuracy) of Single State Models
  7.3 Comparison of TWA and MM Approaches
  7.4 A Single State FADEC System MM Example
      7.4.1 Description of the Excel Spread Sheet Data
      7.4.2 Validity of the Calculated Data
  7.5 Second Example: A Single and Dual State Model of a FADEC
      System
  7.6 Discussion of Markov Model and TWA Approaches, and the Use
      of Fault Trees for Determining LOTC Rates Men Operating
      With Faults
  7.7 Time-Since-Fault (i.e., On-Condition) Repair Versus
      Periodic Inspection and Repair
8 CALCULATION APPROACHES: DUAL ENGINE ANALYSIS
  8.1 Time-Averaging Approach
  8.2 Maximum Specific Risk Failure Rates as a Function of
      Dispatch Configuration
9 SUMMARY
APPENDIX A EARLY APPLICATIONS
APPENDIX B REVISED FAA ANE POLICY LETTER, ANE-1993-33.28TLD-R1,
           DATED JUNE 29, 2001, POLICY FOR TIME LIMITED DISPATCH
           (TLD) OF ENGINES FITTED WITH FULL AUTHORITY DIGITAL
           ENGINE CONTROLS (FADEC) SYSTEMS
APPENDIX C DISCUSSION OF SOME TYPICAL FADEC SYSTEM FAULTS
           AND THEIR APPLICABILITY TO THE LOTC ANALYSIS
APPENDIX D DISCUSSION OF THE MMEL, DDG, CMRS, AND THEIR
           RELATIONSHIP TO FADEC SYSTEM MAINTENANCE
           (THE HANDLING OF ND, ST, AND LT FAULTS)
APPENDIX E PROBABILITY OF A DUAL ENGINE FAILURE WITH DIVERSION
           AND TURNBACK
APPENDIX F A REVIEW OF THE COEFFICIENTS USED IN THE
           TIME-WEIGHTED-AVERAGE (TWA) EQUATION, ALONG WITH A
           DISCUSSION OF (1) THE COEFFICIENTS USED IN A SINGLE
           STATE MARKOV MODEL, WHICH MAINTAINS ALL OF THE SINGLE
           ST AND LT STATES AS SEPARATE STATES, AND (2) THE
           COEFFICIENTS OF A SINGLE STATE MARKOV MODEL, WHICH
           COMBINES ALL ST AND LT FAULTS INTO A SINGLE (AVERAGE)
           ST AND LT STATE
APPENDIX G MEN IS A SINGLE STATE MODEL OK?
APPENDIX H COMPARISON OF THE ASYMPTOTIC VALUE OF {(dP/dt)/(1 - P)}
           IN AN OPEN LOOP MARKOV MODEL WITH THAT OF THE AVERAGE
           FAILURE RATE OF THE SYSTEM FROM A CLOSED
           LOOP MARKOV MODEL

Provides methodologies and approaches which have been used for conducting and documenting the analyses associated with the application of Time Limited Dispatch (TLD) to the thrust control reliability of Full Authority Digital Electronic Control (FADEC) systems.