Message Name:

CAS CAUTION FLAG

The amber 'CAS' message on the PFD indicates that the system has failed and CAS messages are not available.

• The Data Concentration function provides centralized concentration of discrete, analog, and serial data collected from various aircraft systems.
• The input data is packed onto a serial output bus for use by other functions including but not limited to:

  1. Crew Alerting,
  2. System Indication,
  3. Maintenance and Diagnostics,
  4. Flight Data Acquisition.

  If the EICAS display looses communication with the DCU, the message is posted.

• Data Concentrator Unit (DCU) (A14)

Advisory Wire/Service Bulletins: None

Forum Articles/Infoservice/Newsletter: None

None

1. The input and output data is processed at a predefined rate that does not demand a data request or hand-shaking from the using functions.
2. In the event that a DCU has redundant bus inputs, one will be specified as primary, the other secondary. Labels will be used from the primary source as long as they pass the normal integrity and validity checks. In the event that a label becomes invalid, the last valid value will be used for up to three samples.
3. If after four consecutive samples the label is invalid, the DCU will begin using data from the other source. The DCU will return to the primary source if the data becomes valid. This selection process is done on a label-by-label basis.
4. Fault isolation is available through the MDC system to view current faults.