- UNABLE REQD NAV PERF-RNP Message:
Notes:
- The UNABLE REQD NAV PERF - RNP message
shows when the Actual Navigation Performance
(ANP) exceeds the Required Navigation
Performance (RNP) for the current flight
environment. The map data is not blanked in this
condition. The flight crew must select a reliable
navigation source from the FMC. Check POS
SHIFT page for corrupted data. Update with the
best NAV sensor data values GPS, DME, or VOR
via the MCDU. The FMC position may be overridden by selection of the particular navigation sensor position with the line select key. The selected sensor will now be highlighted and the EXEC light will come on. When you select EXEC, the FMC navigation position changes to the selected sensor position and UPDATE COMPLETE will show at line 5L in small font.
RNP Possible Causes:Before replacing any component perform BITE of corrupted data source, if known.
1.Flight Management Computer (FMC)
2.Toggling the FMC selector to BOTH on 1 then BOTH on 2, back to NORMAL
RNP Message:
Circuit Breakers:FMCS CMPTR #1: P18-2 = E8 & A6.
FMCS CMPTR #2: P6-1 = D16.
DME #1: P18-1 = B3.
DME #2: P6-1 = A14.
MMR#1/ILS#1: P18-1 = A2.
MMR#2/ILS#2: P6-1 = A13.
VOR #1: P18-1 = A1.
VOR #2: P6-1 = A12.
Applicable deferrals MEL 34-36 Flight Management Computer SystemMEL 34-36 MCDU/CDU
MEL 34-36 FMC Alert Lights
MEL 34-36 Navigation Database
- The UNABLE REQD NAV PERF - RNP message
shows when the Actual Navigation Performance
(ANP) exceeds the Required Navigation
Performance (RNP) for the current flight
environment. The map data is not blanked in this
condition. The flight crew must select a reliable
navigation source from the FMC. Check POS
SHIFT page for corrupted data. Update with the
best NAV sensor data values GPS, DME, or VOR
via the MCDU. The FMC position may be overridden by selection of the particular navigation sensor position with the line select key. The selected sensor will now be highlighted and the EXEC light will come on. When you select EXEC, the FMC navigation position changes to the selected sensor position and UPDATE COMPLETE will show at line 5L in small font.