03/16/22
Message Overview:
Message Name:
FMS/GPS MON UNAVAL (CYAN) ON SCRATCHPAD
| Message Code: | 346OBS007 |
| Effectivity: | All |
| System: | Flight Management System |
| System Description: | 34-60-00 |
| Schematic Diagram: | None |
| Wiring Diagram: | None |
Message Description:
The Flight Management System (FMS)/Global Positioning System (GPS) position monitor is not available.
Possible Causes:
- Global Positioning System (GPS) Sensor
Troubleshooting Tips:
Advisory Wire/Service Bulletin: None
Forum Articles/Infoservice/Newsletter:
- Forum - Volume 18. Issue 02 (January 28, 2021) - Global navigation satellite system: interference, signal loss and jamming
The FMS/GPS MON UNAVAL message is not an indication of a defect in the system, LRU or the interface. The message shows that the position monitor cannot use the GPS sensor. For aircraft with a dual GPS system, the message will show if the data from the two GPS sensors is invalid. The message goes off when one of the GPS positions is valid and its HIL is not more than 0.30 nm. Thus the fault isolation procedure is not applicable for this message.
Flight Operation Notifications Manual (FONM):
- FONM - AVNC-030-A - GNSS Outage due to Signal Degradation or Jamming with Associated FDE
Quick Links:
None
Troubleshooting Recommendations:
None