Downloaded from https://www.everyspec.com ADS-79D-HDBK and by a review of the recorded state parameter time history data with comparison to maneuver descriptions and tolerances used during the flight load survey. The purpose of these flight tests is to verify that the usage monitoring system can identify the significant regimes of the usage spectrum including highly damaging maneuvers and benign maneuvers with high frequencies of occurrence. The maneuvers will be flown 3 times with 3 different pilots for a total of nine repeated flights of all critical regimes.
The repeats are planned to address the variability introduced by pilot technique in order to assess this influence on regime identification and classification. Data collection and processing will utilize the onboard and ground software and hardware proposed for structural monitoring of fleet aircraft. The data integrity checking process will be demonstrated. B.5.4.6 Unscripted flights. The unscripted flights should be performed to verify that execution of continued airworthiness utilizing the structural monitoring system will meet or exceed the safety requirements defined in Appendix A of this ADS.
Actual fleet usage of the aircraft may involve maneuvering that does not fit neatly into precisely defined regime bins. Therefore, this effort will include flight testing of a load/strain instrumented aircraft, comparison of loads and comparison of fatigue damage for simulated missions. The missions and associated usage will be representative of the regime environment in which the monitoring system will be used. Likewise, usage data will be collected and processed utilizing the onboard aircraft and ground software and hardware proposed for fleet airworthiness management. B.5.4.7 Flight testing.
A goal of the mission flight testing is to provide multiple repeats of both commonly flown missions or mission segments and also missions segments that are less frequently performed, but could result in high fatigue loads. Identified missions should be flown a minimum of 3 times. A minimum of 3 operational pilots should be utilized such that each trial of the same mission is flown by a different pilot. Extensive steady level flight elements of missions such as transit legs can be eliminated from the test mission flights; however, transit time which includes contour flight should be included for a representative length of time. B.5.4.8 Comparison of loads.
Measured loads should be separated into the regimes identified by the structural monitoring system. These loads will be compared to the Top of Scatter (TOS) loads measured in Flight Loads Surveys and utilized in establishing the current fatigue lives of the selected components. The goal is to identify the magnitude of the TOS load relative to the load distribution of the selected regime. For example a 95% load would have only 5% of the loads in the distribution larger than the TOS load. This is a significant input when evaluating the reliability of structurally monitored damage fraction calculations. B.5.4.9 Comparison of damage fraction.
The damage calculated from the measured loads for each mission should be compared to the damage predicted by using the usage identified by the monitoring system and the TOS loads for each of the identified regimes. Direct comparisons should be made of within maneuver, maneuver to maneuver, and GAG damage and overall flight damage. The damage calculated for measured loads per maneuver will use rainflow cycle counting 14 to pair maximum and minimum loads. This damage will be compared to the damage calculated utilizing TOS loads and the procedure for maneuver to maneuver and GAG as documented in the aircraft‘s fatigue methodology report.
Overall flight damage will be calculated from rainflow cycle counted loads from flight start to flight end for comparison to the usage based damage sum and the maneuver load based damage sum. 14 ―ASTM E1049-85 Standard Practices for Cycle Counting in Fatigue Analysis‖ 60