When should ARINC be monitored?

• A. When ACARS is not working
• B. During fueling
• C. During takeoff
• D. During landing

Answer: (A)

ARINC is the data-link standard that carries ACARS messages on the aircraft. Monitoring ARINC is part of troubleshooting ACARS issues because it lets you verify the health of the underlying data bus independent of the ACARS software. If ACARS isn’t working, you check ARINC to see whether the problem lies on the bus—such as faults on the ARINC channels, bad connections, or framing errors—or elsewhere. During fueling, takeoff, or landing there isn’t a routine need to monitor ARINC unless a specific ACARS problem is present; the monitoring is specifically to diagnose ACARS failures. So the best course is to monitor ARINC when ACARS isn’t functioning.