FMC FAIL(review) in GUM

P6-1D
P18-2A

Transfer Bus 1 Sect 1 - 115v ac
Standby Bus Sect 1 - 115v ac (as wired)
Transfer Bus 2 Sect 2 - 115v ac (optional FMC 2)

Condition : “FMC” message or MENU page on both (M) CDU.
Other indications are LDG ALT message displayed on the altimeter
(because the landing field elevation is missing) and A/T LIM on the TMAP.

(As installed) The MCDU remains available for ACMS - ACARS functions.

ON GND

• Refer to MEL 34-36 [Flight Management Computer System (FMCS)]
  File a new flight plan without RNAV capability.

• Enter the aircraft parking position through ISDU on aft OVHD panel

• Obtain takeoff thrust setting in FPPM or PI [General - Takeoff %N1]
  Verify if your SOP allow reduced thrust with (both) FMC inoperative.
  Calculate also climb %N1 for thrust reduction after takeoff and the maximum continuous %N1 for an engine failure on takeoff. For te latter, use table PI [Engine Inoperative - Max Continuous %N1 - 10000 FT to 1000f FT]. Insert N1 via the N1 SET knob as follows :

SP 7.x [Setting N1 Bugs with an Inoperative FMC]

• select BOTH and insert N1
• leave the knob in BOTH, do not return to AUTO

Insert V1 and VR via the SPD REF selector as follows :
SP 10.x [Setting Airspeed Bugs with an Inoperative FMC]

• select and insert V1 (to display V1 on speed tape)

• select and insert VR (to display R on speed tape)

• select and insert WT (for flaps maneuvering speeds)

• select SET

• The A/T is not available for takeoff, however, the A/T can be used in flight.
  Nevertheless, press TO/GA on takeoff to engage the F/D.

In FLT

• LNAV and VNAV are no longer availble. Advise ATC “UNABLE RNAV”.
  Use conventional navigation with VOR mode. MAP mode can still be used for navigation to intersections (select STA and WPT). The FMC is not required for CAT II/III approach and not for RVSM.

• Obtain final approach speed from PI [General - VREF].
  Insert VREF and landing weight via the SPD REF selector as follows :

SP 10.x [Setting Airspeed Bugs with an Inoperative FMC]

• select and insert VREF (to display REF on speed tape)

• select and insert WT (to display all flaps maneuvering speeds)

• select SET

• Obtain the G/A thrust setting from PI [General - Go-Around %N1].
  Insert the N1 setting via the N1 SET knob as follows :
  SP 7.x [Setting N1 Bugs with an Inoperative FMC]

• select BOTH and insert N1

• leave the knob in BOTH, do not return to AUTO

RIGHT FMC FAIL (DUAL FMC - As installed)

SOP - B-RNAV requires only one FMC. Both FMC must be available for P-RNAV.
The message “SINGLE FMC OPERATION” appears on the CDU screen. LNAV and VNAV are not available on Autopilot B.

VTK amber annunciation appears on the right ND. If the VTK amber annunciation does not appear, the right FMC did not fail, but both FMC data disagree Position the FMC Source Select Switch to BOTH on FMC L to resynchronize the right FMC. The message DUAL FMC OP RESTORED appears when resynchronization is completed.

LEFT FMC FAIL (DUAL FMC - As installed)

SOP - B-RNAV requires only one FMC. Both FMC must be available for P-RNAV.
The following illustration shows dual FMC normal operation and FMC-L failure.