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Challenger 300 first officer reported navigational problems relating to FMS and GPS issues.
| Attributes | |
| ACN | 1653893 |
| Time | |
| Date | 201906 |
| Local Time Of Day | 0601-1200 |
| Environment | |
| Light | Daylight |
| Aircraft 1 | |
| Make Model Name | Challenger 300 |
| Operating Under FAR Part | Part 91 |
| Flight Phase | Parked |
| Flight Plan | IFR |
| Component | |
| Aircraft Component | GPS & Other Satellite Navigation |
| Person 1 | |
| Function | Pilot Not Flying First Officer |
| Qualification | Flight Crew Multiengine Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument |
| Experience | Flight Crew Last 90 Days 100 Flight Crew Total 21000 Flight Crew Type 150 |
| Events | |
| Anomaly | Aircraft Equipment Problem Less Severe Deviation - Procedural Published Material / Policy |
Narrative:
When aircraft was powered up; we noted a message on the flight management system (FMS) CDU's stating 'gnss [global navigation satellite system] not available'. We checked the status page for faults; and noted that neither GPS was acquiring satellite signals. We initially attributed it to the fact that we were surrounded by metal buildings; and that the gnss system would eventually acquire the constellation. In addition to gnss navigation; our aircraft is configured with an IRU with DME/DME updating to the FMS. As such we met all required navigation performance for our flight(s).after leg 1; we discovered that there was a nationwide anomaly with gnss systems of a particular make and model; which affected many aircraft; other than ours. We operate using the bombardier master minimum equipment list (mmel). The mmel states that one gnss system must be operable for dispatch. However; as the anomaly was not based within our on board system; we agreed that the continued operation was allowable. During our last leg; we received a message from our company that this anomaly did indeed fall under the control of the mmel; and as such all company aircraft with the affected gnss system were not suitable for flight.as stated above; with IRU-DME/DME updating to the FMS; we met all rnp requirements for the operations conduction. As such; there was no degradation of safety during any portion of our day's flights.
Original NASA ASRS Text
Title: Challenger 300 First Officer reported navigational problems relating to FMS and GPS issues.
Narrative: When aircraft was powered up; we noted a message on the Flight Management System (FMS) CDU's stating 'GNSS [Global Navigation Satellite System] NOT AVAILABLE'. We checked the status page for faults; and noted that neither GPS was acquiring satellite signals. We initially attributed it to the fact that we were surrounded by metal buildings; and that the GNSS system would eventually acquire the constellation. In addition to GNSS navigation; our aircraft is configured with an IRU with DME/DME updating to the FMS. As such we met all required navigation performance for our flight(s).After leg 1; we discovered that there was a nationwide anomaly with GNSS systems of a particular make and model; which affected many aircraft; other than ours. We operate using the Bombardier Master Minimum Equipment List (MMEL). The MMEL states that one GNSS system must be operable for dispatch. However; as the anomaly was not based within our on board system; we agreed that the continued operation was allowable. During our last leg; we received a message from our company that this anomaly did indeed fall under the control of the MMEL; and as such all company aircraft with the affected GNSS system were not suitable for flight.As stated above; with IRU-DME/DME updating to the FMS; we met all RNP requirements for the operations conduction. As such; there was no degradation of safety during any portion of our day's flights.
Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.