Central Warning System
The central warning system includes the Crew Alerting System (CAS) function and the RPM annunciator. The CAS is a function of the general computers that provide alert messages to the central display system and audio integrating system. It reports any failure of a system, or parameter exceedance that need the pilot’s attention and can affect the safety of the flight. The RPM annunciator gives the warning in case of high or low rotor RPM.
Crew Alerting System (CAS)
The Crew Alerting System (CAS) is provided by the G1000H NXi Integrated Avionics System (IAS) by monitoring engine and airframe parameters. Visual indications are provided through the Primary Flight Display (PFD) and the Multi-Function Display (MFD), while associated audio alerts are provided through the audio panel (GMA) and crew headsets.
The CAS gives the types of messages that follow:
Master WARNING/CAUTION Annunciations and acknowledgment softkey in lower right corner of PFD in normal mode, or PFD/MFD in reversionary mode.
Instrument panel mounted RPM Annunciator
CAS windows on the PFD and MFD
Audio alerts
Warning messages will always be displayed at the top of the CAS window and cannot be scrolled.
CAS display (PFD)
When CAS messages are generated, a CAS window containing messages appears to the right of the vertical speed indicator on the PFD. Up to 12 messages can be displayed in this window. When more than 12 messages accumulate, the CAS softkey becomes available. Pressing the CAS softkey displays softkeys for scrolling up and down through the messages in the PFD CAS window. In reversionary mode, the CAS softkey takes the place of the INSET softkey.
Engine page CAS display (MFD)
CAS alerts are additionally displayed on the upper left of the Engine Indication System (EIS) Engine page on the MFD. Up to 19 messages can be shown on this page. When more than 19 messages accumulate, the CAS softkeys become available to permit scrolling up and down through the messages on the page.
CAS messages are grouped by criticality (Red = WARNING , Amber = CAUTION , White = ADVISORY , and Green = STATUS ) and sorted by order of appearance (most recent messages on top). The color of the message is based on its urgency and on the required action.
WARNING (red) - Immediate crew awareness and immediate crew action required: accompanied by one or more audio alert tones: and a Master WARNING CAS Annunciation in the lower right corner of the PFD in normal mode, or PFD/MFD in reversionary mode.
CAUTION (amber) - Immediate crew awareness and subsequent corrective action required: accompanied by one or more audio alert tones: and a Master CAUTION CAS Annunciation in the lower right corner of the PFD in normal mode, or PFD/MFD in reversionary mode.
ADVISORY (white) Crew awareness required and subsequent action may be required.
STATUS required. (green) Crew awareness
In the event of momentary triggering, WARNING and CAUTION messages can be displayed as flashing messages for up to three seconds and will then extinguish.
A CAS message does not appear more than once at any given time. Upon initial triggering (i.e. transition of the CAS message condition to true), WARNING and CAUTION messages will be displayed flashing. The flashing message will persist until acknowledged by pressing the Master WARNING/CAUTION acknowledgment softkey in the lower right corner of PFD in normal mode, PFD/MFD in reversionary mode, or until the triggered condition is inactive for more than three seconds. After the Master WARNING/CAUTION acknowledgment softkey is pressed, and if the message condition is still true, the message will become steady and will remain displayed at the top of its respective priority group in the CAS window until either a newer message of the same priority appears or until the condition which triggered the message goes inactive, at which time the message will be removed.
ADVISORY CAS messages flash for five seconds and are then automatically acknowledged. The message will remain displayed until the condition which triggered the message goes inactive, at which time the message will be removed. In specific regards to an ECU MAINT CAS message due to an exceedance, this message will remain latched as active until cleared by maintenance action.
STATUS messages are automatically displayed. They will remain displayed until the condition which triggered the message goes inactive, at which time the message will be removed.
CAS messages - Listing and Activation Logic
The term "Logging" refers to information about a specific CAS message being recorded in the MFD Diagnostic and Maintenance Data Information or in the FADEC Electronic engine Control Unit (ECU).
Activation Logic: CAS message will be displayed in the CAS window and logging shall begin per defined logic
Clear Logic: CAS message will be removed from the CAS window and logging for message will no longer be continued per defined logic
Mask Logic: If CAS message is active, it will be removed from the CAS window and logging for this message will continue until the clear logic for the message is triggered. If masking logic is active and the CAS message activation logic is triggered, the CAS message will not be displayed in the CAS window and logging for this message will continue until clear logic for the message is triggered.
Inhibit Logic: CAS message will be prevented from being displayed in the CAS window and will not be logged per defined logic.
WARNING CAS MESSAGES
| Message | Description | Activation Logic | Clear Logic | Inhibit Logic |
|---|---|---|---|---|
BATTERY HOT | Battery overheat detected. Possible causes are as follows:
| Battery Temperature > 100°C (212°F) | Battery Temperature < 55°C (131°F) | N/A |
ECU FAIL | Total ECU failure (FAILURE 3) | Loss of Q, ECU CHA & CHB AND Loss of MGT, ECU CHA & CHB AND Loss of NG, ECU CHA & CHB AND Loss of NP, ECU CHA & CHB AND Loss of Engine Oil Pressure, ECU CHA & CHB AND Loss of Engine Oil Temperature, ECU CHA & CHB AND Loss of Fuel Flow, ECU CHA & CHB | N/A | |
CAUTION MESSAGES
ADVISORY MESSAGES
STATUS MESSAGES
Audio Alert Activation and Description
All warning and caution Crew Alerting System (CAS) messages as well as specific Garmin G1000H NXi IAS features are associated with audio alerts. The associated audio alerts are as follows:
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RPM annunciator
The RPM annunciator gives the warning to the pilot that the main rotor RPM is above or below the safe operating margin. It is located on the instrument panel in front of the pilot.
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