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MCDU Messages

Messages displayed on the MCDU are of two types and displayed in two colors.

  • Type I : A direct result of a pilot action;
  • Type II : Information about a situation, or a call for pilot action;
  • Type II messages are stored in a first-in/first-out message queue (5 messages max)
  • They are suppressed if correct data is entered or when they no longer apply
  • The flight crew can clear all messages by pressing the CLEAR key on the MCDU console.
  • Amber (A) : Important
  • White (W) : Less important
Message Type Conditions
A/C POSITION INVALID II/A The aircraft position has become invalid. If the message has been cleared and the flight crew attempts to call up the HOLD at PPOS or DIR TO page while the aircraft position is still invalid, then the message is displayed again.
(ACARS msg)
II/W A flight plan is stored in the active flight plan.
ALIGN IRS II/A Appears when the IRS are ready for alignment, but the INIT A page is not displayed on either side of the flight deck. The ALIGN IRS message requires that one of the flight crew call up the IRS INIT page, to align the IRS.
AREA RNP IS XX-XX II/A Displayed when the RNP value, manually-entered on the PROG page, is larger than the default RNP value associated to the current flight area and when there is no RNP value defined in the navigation database for the active leg or route.
AWY/WPT MISMATCH I/W The pilot entered VIA on the AIRWAYS page does not contain the revised point. If you enter a second airway IDENT, it must contain the first airway ending point.
BLOCK IGNORES RTA II/W A time constraint existing at initiation of flight planning, or an entry of a time constraint made after initiation of flight planning, are ignored by the fuel planning function.
CABIN RATE EXCEEDED II/W This message appears when the aircraft gets within 200 NM of the destination and the computed rate of descent makes it impossible for the cabin to be repressurized at the maximum rate.
(ACARS msg)
II/W The uplinked alternate cruise flight level differs from the defaulted alternate cruise flight level.
II/W Displayed when a NON-ILS or non GLS approach is part of the F-PLN and an ILS/GLS is manually tuned on RAD NAV page. This message reminds the flight crew that available guidance modes for the approach are APP NAV/FINAL. Displayed when in cruise at less than 100 NM from the top of descent or in descent or approach phase.
(ACARS msg)
II/W The uplinked company route identifier differs from the one specified in the request.
CHECK DATA BASE CYCLE II/W The current date does not match the effective date of the active database, and someone attempts to enter a FROM/TO or CO RTE.
CHECK IRS 1 (2)(3)/FM POSITION II/A Each IRS position is compared to the FM position. The difference is greater than a threshold function of time.
CHECK IRS/AIRPORT POS I/A The distance between ADIRS alignment position and the NAV Database Airport Reference Point is at least 5 NM
(ACARS msg)
II/A The aircraft is at 180 NM from destination and the destination QNH, TEMP or WIND displayed on the PERF APPR page received by ACARS uplink has to be checked. If a modification of these parameters is performed creating a conflict with previous data, the message is triggered again.
(ACARS msg)
II/A The uplinked flight number differs from the flight number specified in the request.
CHECK MIN DEST FOB II/W This message appears when the flight crew has manually entered the MIN DEST FOB value, and MIN DEST FOB < ALTN + FINAL, being FINAL an ALTN valid data.
CHECK NORTH REF * EFIS ND II/A The MAG/TRUE sw does not correspond to the airport MAG/TRUE bearing reference (as stored in the FMGS navigation database), either at the departure airport (during preflight), or at the destination airport (when entering the ARRIVAL area).
CHECK QFE II/A This appears at the transition from QNH to QFE reference, when the QFE altitude differs by more than 100 ft from the predicted altitude, with the QNH set on the MCDU by means of the airport elevation in the NAV database.
CHECK TAKEOFF DATA II/A Following a flight crew entry or modification of one of the take-off parameters, there may be an inconsistency between the take-off runway or the TO shift and V1, VR, V2, FLEX TO temperature or derated level. The flight crew activated the secondary F-PLN in PREFLIGHT or DONE phase.
CHECK WEIGHT II/A The gross weights (GW) computed by the flight management computer (FMC) and the flight augmentation computer (FAC) disagree by more than 7 t (7.7 US tons).
CLK IS TAKEOFF TIME II/W This appears when the flight crew has entered an Estimated Takeoff Time (ETT), and the actual time is equal to ETT.
CLOCK/GPS TIME DIFF XX II/A Aircraft clock time and GPS time differ by more than XX minutes.
CROSSLOAD ABORTED II/W Message displayed on the transmitting MCDU, indicating an error in the transmission process.
CROSSLOAD COMPLETE II/W The database crossload from one FMGC to the other was successfully completed.
CRZ FL ABOVE MAX FL II/W This appears when the flight crew enters a cruise altitude that is above the computed maximum altitude.
CSTR DEL ABOVE CRZ FL II/W This appears when a flight plan altitude constraint has been deleted because the flight crew has inserted a cruise flight level, or step-down altitude that is at or below the flight plan constraint.
CSTR DEL UP TO WPT 01 II/W This appears when constraints get deleted because the aircraft transitions to a go-around flight phase, before the FMGS sequences the flight plan destination.
(Also displayed on PFD)
II/W One of these messages appears when the aircraft has reached the T/D in managed speed and it has not yet begun the descent.
DELETING OFFSET II/W This appears when the system is deleting an offset automatically, which it does under certain specific conditions, such as:
- Change of active leg due to lateral revision.
- Termination of next leg at destination runway and the current distance to go is less than or equal to the distance required to reach the path, or the next leg is not a CF, FM or TF leg.
DEST/ALTN MISMATCH I/W The pilot attempts to enter an alternate CO RTE which starts at an origin that is not the primary flight plan destination.
DEST EFOB BELOW MIN II/A The EFOB at destination calculated by the FMS is less than the MIN DEST FOB value specified on the FUEL PRED page, for more than 2 min. The message is triggered in flight, except during Takeoff and Climb phases.
DIR TO IN PROCESS I/W The flight crew calls up the vertical or lateral revision page on one MCDU while the direct to page is displayed on the other MCDU.
ENTER DEST DATA II/A The flight crew has not entered wind, QNH, or temperature for the destination, and the aircraft is 180 NM out.
ENTRY OUT OF RANGE I/W The flight crew attempts to enter data that is out of the range specified for the selected field.
(ACARS msg)
II/W A flight number has been added to the uplink flight plan without previous request.
F-PLN ELEMENT RETAINED I/W The flight crew attempts to delete stored NAVAIDs, waypoints or runways that are contained in any flight plan or that are being tuned.
F-PLN FULL II/W There is not enough memory in the flight plan allotment for the computer to accept more flight plan data.
FMS 1/FMS 2 A/C STS DIFF II/W This message always precedes a transition to independent mode, and appears at power-up if the system detects a difference in one of the following:
- NAV database serial number
- Performance database
- FM operational program
- Aircraft and airline program pins
FMS 1/FMS 2 GW DIFF II/W Onside and offside aircraft weight differ by 2 t or more.
FMS 1/FMS 2 PGM PIN DIFF II/W Onside and offside program pins are different.
FMS 1/FMS 2 POS DIFF II/A Onside and offside positions differ by 0.5 NM or more (5 NM when GPS is not installed).
FMS 1/FMS 2 SPD TGT DIFF II/W Onside and offside target speeds displayed on the PFD differ by 5 kt or more.
FORMAT ERROR I/W A data entry does not meet the specified entry format for a given field.
(also displayed on ND)
II/A Displayed when GPS PRIMARY mode is lost.
GPS PRIMARY II/W Displayed when the FMS is transitioning to GPS PRIMARY
GPS IS DESELECTED II/A This message appears when GPS has been manually deselected and the aircraft is 80 NM before the top of descent or in approach phase.
INDEPENDENT OPERATION II/A The FMGCs operate independently of each other.
INITIALIZE WEIGHT/CG II/A The zero-fuel weight or block fuel (FOB) is undefined after engine start.
(ACARS msg)
II/W The uplink message contains a valid flight plan but no flight number.
(ACARS msg)
II/W Performance uplink message has been rejected.
(ACARS msg)
II/W An error was detected into the uplink message and it is rejected.
(ACARS msg)
II/W The current uplink takeoff data message is rejected.
(ACARS msg)
II/W The current uplink wind message is rejected.
LAT DISCONT AHEAD II/A The next leg is a discontinuity and the aircraft is 30 s from flying the leg.
LIST OF 10 IN USE I/W The flight crew has tried to enter more than ten stored runways into the database, and all of the first ten are included in a flight plan or a pilot-stored route.
LIST OF 20 IN USE I/W The flight crew has tried to create a PBD, LAT/LONG, or PBX, or store a pilot-defined waypoint or NAVAID when 20 are already in use (in a flight plan or pilot-stored routes).
MACH SEGMENT DELETED II/W A constant Mach segment of the active flight plan has been automatically deleted. This occurs when the secondary flight plan or the alternate is activated, or engine out is detected or when the flight phase changes from CRZ to another one.
MCDU OVERHEATED II/A This message is displayed for 15 s in case of MCDU overheating.
II/W DES mode is engaged, idle is selected and the aircraft must decelerate in order to recover the path, or to respect an altitude constraint, a speed limit or a speed constraint.
(also displayed on ND)
II/A NAV accuracy has been downgraded from HIGH to LOW. (See FMGS principles for an explanation).
II/W NAV accuracy has been upgraded from LOW to HIGH.
NEW ACC ALT-HHHH II/W The acceleration altitude has been changed.
NEW CRZ ALT-HHHHH II/W The cruise altitude has been changed.
NEW THR RED ALT-HHHH II/W The thrust reduction altitude has been changed.
(ACARS msg)
I/W A crew request, was previously sent to the ground and no answer has been received for 4 min.
NO INTERSECTION FOUND I/W The system could not find any common waypoint nor intersection point through the airway.
NON UNIQUE ROUTE IDENT I/W The flight crew has tried to enter on the new route page a company route IDENT that is identical to an existing company route IDENT (pilot-defined or in the database).
NOT ALLOWED I/W Data entry is not allowed in the selected field, or a selection action is not allowed.
NOT ALLOWED IN NAV I/W An attempt to modify the TO waypoint is made while in NAV
NO NAV INTERCEPT II/A It is triggered, when NAV mode is armed and, no INTERCEPT waypoint exists before the TO waypoint.
NOT IN DATA BASE I/W The pilot is trying to enter or call up a company route IDENT, a FROM/TO pair, a place defined by place-bearing-distance (PBD) or place-bearing/place-bearing (PBX) or an airport NAVAID, waypoint runway, or NAVAID frequency/channel (including pilot-defined elements) that is not in the current database.
(ACARS msg)
II/W A pilot request or a crew report was sent but the communication was not established or not acknowledged.
ONLY SPD ENTRY ALLOWED I/W The pilot is trying to enter a Mach number for a preselected speed value on the CLIMB page.
OPP FMGC IN PROCESS II/W The offside FMGC is unhealthy, and the FM system mode is SINGLE. The message indicates that the MCDU on which the message is displayed is being driven by the FMGC on the other side.
PAGE UPDATE IN PROCESS I/W The pilot presses a key on the flight plan page while predictions are being updated.
(ACARS msg)
II/W Performance data are received from ground.
PLACE/D IN TRANSITION I/W If a place/distance waypoint is defined within a pre-planned “fixed turn radius” transition, the entry is rejected and the “PLACE/D IN TRANSITION” scratchpad message is displayed.
PLEASE WAIT I/W Resynchronization between both FMGCs is in progress.
PROCEDURE RNP IS XX.XX II/A Displayed when the RNP value, manually-entered on the PROG page, is larger than the RNP value defined in the navigation database for the active leg or route.
(ACARS msg)
II/W A printer communication error has been detected while printing a report. The printing is terminated.
RADIONAV IS DESELECTED II/A Radio navaids have been manually deselected and the aircraft is 80 NM before the top of descent or in approach phase.
REF/GPS POS DIFF I/A This message is displayed when there is a discrepancy between the reference position entered by the pilot and the GPS position.
REF/LAST IRS POS DIFF I/A This message is displayed when there is a discrepancy between the reference position entered by the pilot and the last stored IRS position.
REVISIONS NOT STORED II/W This message, displayed when a pilot-defined route or company route (active or secondary flight plan) is stored, indicates that the following elements are not retained:
- Pilot-entered holds
- Offsets
- Modifications to terminal area procedures
- Pilot-entered constraints
- Pseudo waypoints
- Step at optimum.
RTA DELETED II/W A time constraint is automatically deleted:
- In case of engine-out
- When entering the holding pattern
- In case of go-around
- At phase transition from descent or approach to climb or cruise
- When a time constraint is inserted in the same flight plan at a different waypoint
- When the alternate flight plan is activated
- When a DIR TO/ABEAM is performed, only if the time constrained waypoint is projected as an ABEAM waypoint
- The time constrained waypoint is cleared or sequenced (regardless of active lateral mode)
- Valid clock data is lost
- The time constraint belongs to the active flight plan and the secondary flight plan is activated
- The time constraint belongs to the secondary flight plan and COPY ACTIVE is performed.
RTA EXISTS I/W Displayed if the pilot tries to clear an estimated takeoff time defined by the system.
(ACARS msg)
I/W A flight plan modification is performed after a F-PLN INIT request has been sent. This message is displayed until the uplink is entirely received.
RWY/LS MISMATCH II/A - During climb, cruise, (ILS or GLS) descent approach, or go-around, the LS frequency entered on the RAD NAV page does not match the LS associated with the destination runway.
- During preflight or takeoff, the LS frequency entered on the RAD NAV page does not match the LS associated with the takeoff runway.
(ACARS msg)
II/W A flight plan is stored in the secondary flight plan.
(also displayed on the ND)
II/A The MAG/TRUE sw is set to MAG, while the IRS send true HDG/TRK.
SENSOR IS INVALID I/W - The pilot has selected FF or FQ, or FF + FQ, or FQ + FF on the FUEL PRED page and the sole sensor or both of the selected sensors are invalid, or
- The flight crew has entered fuel on board only, and the FF sensor is invalid.
(SET GREEN DOT displayed on PFD)
II/W (W) This message appears when the following conditions are all met:
- Engine-out condition
- Aircraft in selected speed mode
- FCU-selected speed equal to or greater than green-dot speed +10 kt, and ALT* or ALT not active, or FCU-selected speed equal to or less than green-dot speed -10 kt.
(also displayed on PFD)
II/W (W) This instruction appears when the aircraft is in selected speed, the pilot has inserted a hold in the flight plan, the aircraft is 30 s or less from the point where it must start decelerating towards hold speed, and the selected speed differs from the hold speed by more than 5 kt.
(Also displayed on PFD)
II/W (W) The target speed is selected for the current phase, but there is no preselected speed for the next flight phase. When this is so, one of these messages is displayed at transitions from climb to cruise, and from climb or cruise to descent. The message is always displayed at the transition to descent from climb or cruise if selected speed is active. It is not displayed if managed speed is active.
SETTING SPD/RTA II/W Displayed when the system recomputes its managed speed target to satisfy the RTA constraints.
SPECIF NDB UNAVAIL II/A The NDB to be autotuned (specified for a NDB approach) is not available.
(also displayed on ND)
II/A - The VOR, VOR-DME, or VORTAC to be autotuned (specified for an RNAV or VOR approach) has previously been deselected by the flight crew, or
- The bearing, the frequency, or the IDENT of the VOR (or VORDME or VORTAC) to be autotuned is invalid.
SPD ERROR AT WPT 01 II/W In lateral managed flight, the system predicts that the aircraft will miss a speed constraint by more than 10 kt. When the prediction changes to bring the miss within 5 kt, the message is cleared.
SPD LIM EXCEEDED II/A The aircraft is more that 150 ft below the speed limit altitude and more than 10 kt over green dot or the speed limit (which ever is smaller).
STEP ABOVE MAX FL II/W The pilot has entered a step altitude that is above the predicted maximum altitude.
STEP AHEAD II/W Indicates that the aircraft is within 20 NM of the active step point.
STEP DELETED II/W A step has been automatically deleted.
STORED ROUTES FULL I/W The system already contains five pilot-defined routes. (Only five are allowed.)
(ACARS msg)
II/W A takeoff data message is received.
TEMPORARY F-PLN EXISTS I/W The flight crew has selected any key (except ERASE or INSERT) or attempted a flight planning operation on the secondary flight plan while the system is displaying a temporary flight plan.
TIME ERROR AT WPT 01 II/W While the aircraft is in lateral managed flight the FMGC predicts that it will miss a time constraint
TIME MARKER LIST FULL I/W The system already contains four time markers. (Only four are allowed).
TIME TO EXIT II/A The aircraft must leave holding immediately to satisfy fuel reserve requirements. (Extra fuel is zero).
TO SPEED TOO LOW II/A This message appears if the inserted V1, VR, V2 speeds do not satisfy the existing regulatory conditions regarding VMC and VS1G speeds.
TOO STEEP PATH AHEAD II/A The system displays this message in cruise phase if the aircraft is within 150 NM of its destination or in descent or approach phase and in NAV mode and the descent profile contains a segment that is too steep.
TUNE BBB FFF.FF II/A The system cannot autotune the VOR for approach or position because of a manual VOR selection.
TURN AREA EXCEEDANCE II/A This message is displayed 1.5 min before entry of the PI leg, when in NAV mode, if the PI lateral path exceed the protection envelope defined in the Navigation database.
UNKNOWN PROGRAM PIN II/W The system has been unable to initialize because of an incompatible or undefined aircraft pin program combination (A/C type, engine type, VMO/MMO parity) in the FMGC software.
(ACARS msg)
II/W Displayed when an uplink message is currently inserted in the FMGS.
USING COST INDEX-NNN I/W This message is displayed when the system contains a flight plan, and the flight crew tries to enter a zero fuel weight or a gross weight into it before defining a Cost Index (CI). (In this case, the FMS defaults to the Cost Index from the last flight). It is also displayed when the flight crew inserts the ALTN F-PLN (in this case, the FMS defaults the cost index to 0).
V1/VR/V2 DISAGREE II/A This message is displayed when the entered V1, VR and V2 speeds do not satisfy the condition V1 ≤ VR ≤ V2.
WAIT FOR SYSTEM RESPONSE I/W During the time between a subsystem selection and the display of the subsystem page, the MCDU MENU page remains displayed with this message.
(ACARS msg)
II/W Uplink wind message has been received.
(ACARS msg)
I/W A flight plan modification (active or secondary) is attempted when uplink winds are not inserted yet.
(ACARS msg)
II/A A temporary flight plan exists or a DIR TO page is displayed and a wind uplink is received and stored.
XXXX IS DESELECTED I/W The flight crew attempts to enter a deselected NAVAID, via the SELECTED NAVAID page, that has already been deselected.

Last update: September 21, 2022