Radiocommunication priority order
Radio message priority, ten categories, highest first (RIC-21 4.1):
| Rank | Category |
|---|---|
| 1 | Distress communications |
| 2 | Urgency communications |
| 3 | Communications relating to radio direction-finding |
| 4 | Flight safety messages |
| 5 | Meteorological messages |
| 6 | Flight regularity messages |
| 7 | Messages relating to the application of the United Nations Charter |
| 8 | Government messages for which priority has been expressly requested |
| 9 | Service communications relating to the workings of the telecommunication service |
| 10 | All other aeronautical communications |
- Distress: absolute priority over all other transmissions (RIC-21 6.5).
- Station hearing distress call: cease any transmission capable of interfering at once, keep listening on that frequency (RIC-21 6.5).
- Urgency: priority over all other communications except distress (RIC-21 7.2).
Trap: urgency ranks second, only distress outranks it (RIC-21 7.2).
References
- RIC-21 (ISED ROC-A study guide) 4.1
- RIC-21 6.5
- RIC-21 7.2