Engine HMU (Health Monitoring Unit) monitors all engine critical parameters continuously against pre-defined limits and any malfunction will be sent data to HSA.
As a control device, the system performs self-diagnostics to determine overall system status and conveys this information to the pilot by various indicators on the health status annunciator (HSA) panel.
HEALTH STATUS ANNUNCIATOR (HSA)
The Health Status Annunciator (HSA) is located on the primary instrument panel towards the right side, above the electrical switches and aircraft annunciator lights.
The HSA provides indications of primary or secondary (emergency) power malfunctions, erroneous sensor indications, fuel pump malfunctions, and possible misfiring cylinders.
Each HSA annunciator light is associated with a specific system condition. Illumination of a given light indicates that the associated condition has been detected and some response by the pilot may be necessary.
Illumination of the FADEC CAUTION light indicates pressure or temperature sensor failures, abnormal pressure, or temperature above limits, misfire/cylinder not firing, or cylinder not enabled (ignition switch OFF or not in BOTH position).
Illumination of the FADEC WARN light indicates that more than one cylinder is faulted. The FADEC WARN light is always preceded and/or accompanied by illumination of the FADEC CAUTION light.
The EBAT FAIL light illuminates when there is a fault condition with the backup (secondary) power supply. The charging current into the backup battery is too high, indicating: low charge, bad battery, the wire charging the backup battery is not connected, or the primary power source is off or has failed.
Illumination of the PPWR FAIL light indicates that the FADEC system is drawing power from the backup power supply because the primary electrical power supply has been interrupted, the backup power supply potential is higher than the primary buss or the primary power source is off or has failed.
FUEL PUMP indications.