Downloaded from https://www.everyspec.com ADS-79D-HDBK discrete events accumulated. Within this context, detail guidance is provided where benefits can be derived. FIGURE 2. Ideal sensor behavior c. Fatigue life management, through estimating the effect of specific usage in flight states that incur fatigue damage as determined through fatigue testing, modeling, and simulation. Health and Usage Monitoring Systems (HUMS) operation during flight is essential to gathering data for CBM system use, but is not typically flight critical or mission critical as long as the HUMS does not provide actionable input to the pilot or control the aircraft during flight.
When the HUMS is not flight critical, the system should be maintained and repaired as soon as practical to avoid significant data loss and degradation of CBM benefits. As technology advances, system design may lead to more comprehensive integration of HUMS with mission systems. The extent of that future integration may lead to HUMS being part of mission or flight critical equipment or software. In this case, the HUMS bears the same priority as mission or flight critical equipment relative to the requirement to restore its proper operation and requires the same level of software qualification as all flight critical systems.
In the context of data management on the platform, every effort should be made to conform to existing vehicle architectures and common military standards for data acquisition and collection. Military vehicles typically use MIL-STD-1553, Digital Time Division Command/Response Multiplex Data Bus 2 , for sending multiple data streams to vehicle processors. As the use of commercial off-the- shelf (COTS) hardware and software has become more prevalent, the use of commercial standards for data transfer may be acceptable as design standards for CBM in aviation systems. 4.2.1 Embedded diagnostics/prognostics. HUMS has evolved over the past several decades in parallel with the concepts of CBM.
They have expanded from measuring the usage of the systems (time, flight parameters, and sampling of performance indicators such as temperature and pressure) to forms of fault detection through signal processing. The signal processing typically records instances of operation beyond prescribed limits (known as ―exceedances‖), which then could be used as inputs to troubleshooting or inspection actions to restore system operation. This combination of sensors and signal processing (known as ―embedded diagnostics/prognostics‖) represents a capability to provide the 2 MIL-STD-1553B. Digital Time Division Command/Response Multiplex Data Bus. 15 January 1996 . 16