While enroute, the ACARS system becomes inoperative: which statements are correct?

While enroute, the ACARS system becomes inoperative: which statements are correct?

• A. Pilots will tune the applicable ARINC frequency (VHF or HF)
• B. If SELCAL is working properly, the ARINC frequency does not need to be monitored
• C. Both a and b are correct
• D. Neither a nor b are correct

Answer: (C)

When ACARS data link is down, you still need a way to communicate, so you switch to the ARINC voice channel on the appropriate VHF or HF frequency. Tuning that ARINC frequency puts you on the line you’d use for ground and ATC voice traffic as a fallback when the data link is unavailable. At the same time, SELCAL serves as an alerting system for voice calls. If SELCAL is functioning properly, you’ll be notified when a ground station wants to talk, so you don’t have to listen continuously to the ARINC voice channel. In short, you set the ARINC frequency to maintain voice contact, and you rely on SELCAL to cue you to any incoming calls, so both actions described are appropriate in this scenario.

When ACARS data link is down, you still need a way to communicate, so you switch to the ARINC voice channel on the appropriate VHF or HF frequency. Tuning that ARINC frequency puts you on the line you’d use for ground and ATC voice traffic as a fallback when the data link is unavailable. At the same time, SELCAL serves as an alerting system for voice calls. If SELCAL is functioning properly, you’ll be notified when a ground station wants to talk, so you don’t have to listen continuously to the ARINC voice channel. In short, you set the ARINC frequency to maintain voice contact, and you rely on SELCAL to cue you to any incoming calls, so both actions described are appropriate in this scenario.