- Global Position System (GPS) Fail Light:
The GPS has continuous monitor BITE. These are the three ways to detect GPS failures:
- When both GPS system 1 and 2 fail, the amber GPS fail light comes on automatically.
- With a single GPS failure, recall must be activated to illuminate the GPS fail light.
- The FMC SENSOR STATUS page shows MMR failures. The FMC SENSOR DATA page shows the internal failure in the MMR.
GPS Fail Light Possible Causes:Before replacing any component perform BITE if available. Perform a MMR (Multi Mode Receiver bite in the E&E.
1.Multimode Receive (MMR)
2.GPS Antenna's
3.Wiring
Notes: If the flight crew reports a loss of GPS position left and/or right on the FMC POS REF page of the MCDU, with no GPS fail light, perform BITE on the MMR(s). If MMR passes BITE, then replace the GPS antenna on the side that is not showing GPS position.
GPS Light:
Circuit Breakers:MMR#1: P18-1 = A2.
MMR#2: P6-1 = A13.
Applicable deferrals MEL 34-45 Global Positioning System (GPS)