Downloaded from https://www.everyspec.com ADS-79D-HDBK FIGURE M-1. Oil monitoring techniques M.5.2.2 On-aircraft: In on-aircraft debris and oil monitoring, the oil passing through the system is analyzed, providing near-real-time results with minimal outside influence. Testing may be in-line , which evaluates all the oil debris passing through the system. Wear debris on- aircraft applications are currently in use. A portion of the oil flow in direct connection to the lubrication system may also be monitored oil condition. However, on-aircraft applications for oil condition are not presently available . In-line and on-line applications are not mutually exclusive.
At least one of these methods (off-aircraft or on-aircraft) should be employed for both oil debris monitoring and oil condition monitoring. For near-real-time CBM results, on-line (oil condition) and in-line (wear debris) monitoring would offer the most beneficial solution. M.5.3 Sampling Rate: The "optimum (standard) sample interval‖ is derived from failure profile data. It is a fraction of the time between initiation of a critical failure mode and equipment failure. A sampling interval (rate) should be established that is short enough to provide at least two samples prior to failure.
This interval is established for the shortest critical failure mode based on Failure Modes Effects and Criticality Analysis (FMECA). 75 75 ASTM D7669-11, Standard Guide for Practical Condition Data Trend Analysis. 243 Table M-I. Oil monitoring techniques Oil Testing Locations Typical Test Sample Typically Testing For Off-aircraft (off-line) At-line Oil or filter sample Wear debris or fluid condition & contamination Laboratory Oil sample Wear debris and fluid condition & contamination On-aircraft In-line Entire oil flow (full-flow) Wear debris On-line Partial oil flow Fluid condition & contamination