The Boeing 737 MAX aircraft features the MAX Display System, which consists of four large (15-inch), high-resolution displays that provide a clear and concise presentation of flight information.

The Primary Flight Displays (PFDs) present a dynamic color display of all the parameters necessary for flight path control and Failure flags and messages. Failure flags are displayed for airplane system failures. The flag replaces the appropriate display to indicate system failure. Displayed information is blanked or replaced by dashes if no valid information is available to the display system (because of out–of–range or malfunctioning navigation aids).

PFD Failure Flags

  • Distance Measuring Equipment (amber): The DME system has failed.
  • Selected Speed (amber): The selected airspeed data is invalid.
  • Flight Path Vector Flag (amber): FPV is selected on the EFIS control panel, but has failed. Deselection of FPV removes the flag.
  • Speed Limit Flag (amber): Displays related with stick shaker or maximum operating speed has failed:
    • If the stick shaker warning has failed, the red and black stick shaker speed bar is removed.
    • If the maximum operating speed has failed, the red and black maximum operating speed bar is removed.
  • No V Speeds Flag (amber): Displayed when the aircraft is on the ground and both V1 (decision speed) and VR (rotation speed) are not valid or are set to less than 80 knots.
  • Speed Flag (amber): Speed indication is inoperative.
  • Pitch/Roll Comparator Annunciation (amber): PITCH displayed when Captain’s and F/O’s pitch angle displays differ by more than 5 degrees. ROLL displayed when Captain’s and F/O’s roll angle displays differ by more than 5 degrees. The flags flash for 10 seconds then remain steady.
  • Localizer Flag (amber): An ILS frequency is tuned and localizer course indication has failed.
  • Heading Flag (amber): Heading information failed. Heading cannot be displayed.
  • Radio Altitude Flag (amber): Radio altitude indication has failed.
  • Flight Director Flag (amber): The flight director has failed.
  • Glideslope Flag (amber): An ILS frequency is tuned and glideslope indication has failed.
  • Altitude Flag (amber): The altitude display has failed.
  • Vertical Speed Flag (amber): Vertical speed has failed.
  • Attitude Flag (amber): The attitude display has failed.
  • Landing Altitude Flag (amber): The landing altitude input is not available or invalid.
  • Angle of Attack (amber): The AOA signal has failed or is invalid when ground speed is greater than 80 knots.

PFD Annunciations and Alerts

  • AOA DISAGREE Alert (amber)
  • Display System Alerts
  • Displays Control Panel Annunciation (amber)
  • INSTR SWITCH Annunciation (amber)
  • IAS DISAGREE Alert (amber)
  • ALT DISAGREE Alert (amber)
  • Roll/Yaw Asymmetry Alert
  • Roll Authority Alert
  • Roll Command Arrow

AOA DISAGREE Alert (amber)

Angle of Attack (AOA) Disagree Alert – Indicates the Captain’s (left) and First Officer’s (right) AOA values disagree by greater than 10 degrees for more than 10 seconds. The alert is shown on both PFDs and does not indicate which AOA value is erroneous. The AOA DISAGREE alert logic is active when the airplane is above 400 feet RA.

NOTE: If the AOA DISAGREE alert is shown when descending through 400 feet RA, the alert remains until landing.

Display System Alerts

When there is a problem with the DPC display system, one of the following indications will appear in the lower left corner of the primary flight display:

DSPLY SOURCE 1 or 2 (amber) – DPC 1 has failed or DPC 2 has failed. 

Split axis flight director –

  • If a DPC fails above FL220 –
    • the autopilot and flight directors are not affected
  • If a DPC fails during climb or descent below FL220 with the failed side autopilot engaged –
    • the flight director pitch command bar is removed from both pilot’s displays
    • the flight director pitch command bars reappears at ALT ACQ
    • the autopilot engages in CWS P
    • LVL CHG, VNAV, and V/S are not available with the failed side autopilot
  • If a DPC fails during level flight below FL220 with the failed side autopilot engaged –
    • climb or descent to a new altitude is only possible in CWS P
    • initial climb or descent from a new MCP altitude is not possible in LVL CHG, VNAV or V/S modes with the autopilot engaged
  • If the DPC fails on the opposite side as the engaged autopilot or while in manual F/D mode during climb or descent–
    • the flight director pitch command bar is removed from the pilot’s display on the failed side until ALT ACQ
    • climb or descent is possible in LVL CHG, VNAV or V/S modes with the autopilot engaged.
  • If a DPC fails in the approach mode above 400 feet with both flight directors on –
    • the flight director pitch and roll command bars are removed from the display on the failed side
  • If a DPC fails prior to engaging the second autopilot for a dual autopilot approach –
    • engagement of the second autopilot is inhibited.

Displays Control Panel Annunciation (amber)

Indicates a failed EFIS control panel on the affected side. When DISPLAYS CONTROL PANEL appears in the lower right hand corner of the display, altitude information is removed.

With the CONTROL PANEL select switch on the overhead panel in:

  • BOTH ON 1 – Both the Captain’s and First Officer’s displays and baro are controlled from the left EFIS panel
  • NORMAL – Left EFIS panel controls Captain’s displays and baro, Right EFIS panel controls First Officer’s displays and baro.
  • BOTH ON 2 – Both the Captain’s and First Officer’s displays and baro are controlled from the right EFIS panel.

INSTR SWITCH Annunciation (amber)

Instrument Switch Annunciation – Indicates both the Captain’s and First Officer’s displays are using the same source of IRU data. Displayed when the IRS switch on the overhead panel is not in the NORMAL position.

IAS DISAGREE Alert (amber)

Airspeed Disagree Alert – Indicates the Captain’s (left) and First Officer’s (right) airspeed values disagree by greater than 5 knots for more than 5 seconds. The alert is shown on both PFDs and does not indicate which airspeed value is erroneous.

ALT DISAGREE Alert (amber)

Altitude Disagree Alert – Indicates the Captain’s (left) and First Officer’s (right) altitude values disagree by greater than 200 feet for more than 5 seconds. The alert is shown on both PFDs and does not indicate which altitude value is erroneous.

Roll/Yaw Asymmetry Alert

  • Roll/Yaw Asymmetry Alert (amber)
  • Bank Pointer (amber)
  • Slip/Skid Indication (amber)

Roll/Yaw Asymmetry Alert (amber)

Autopilot is engaged in single channel and requires more than 75% of the autopilot roll authority due to unusual asymmetric forces acting on the airplane’s longitudinal axis.

The ROLL/YAW ASYMMETRY alert:

  • replaces the active autopilot status annunciation.
  • is replaced with ROLL AUTHORITY when 100% of the autopilot roll authority is required.
  • is replaced by the active autopilot status annunciation when less than 50% of the autopilot roll authority is required.

Bank Pointer (amber)

With ROLL/YAW ASYMMETRY alert active:

  • bank pointer outline will turn amber.
  • bank pointer will fill amber if bank angle exceeds 15 degrees.

Slip/Skid Indication (amber)

With ROLL/YAW ASYMMETRY alert active:

  • slip/skid indication outline will turn amber.
  • slip/skid indication will fill amber if deflected greater than 25% of its width.

Roll Authority Alert

  • Roll Authority Alert (amber)
  • Bank Pointer (amber)
  • Slip/Skid Indication (amber)

Roll Authority Alert (amber)

Autopilot is engaged in single channel and requires 100% of the autopilot roll authority due to unusual asymmetric forces acting on the airplane’s longitudinal axis.

The ROLL AUTHORITY alert:

  • replaces the active autopilot status annunciation.
  • is replaced by the active autopilot status annunciation when less than 100% of the autopilot roll authority is required.

Bank Pointer (amber)

With ROLL AUTHORITY alert active:

  • bank pointer outline will turn amber.
  • bank pointer will fill amber if bank angle exceeds 15 degrees.

Slip/Skid Indication (amber)

With ROLL AUTHORITY alert active:

  • slip/skid indication outline will turn amber.
  • slip/skid indication will fill amber if deflected greater than 25% of its width.

Roll Command Arrow

  • Bank Pointer (red)
  • Slip/Skid Indication (red)
  • Roll Command Arrow (red)

Bank Pointer (red)

When roll command arrow shown:

  • bank pointer fills red.

Slip/Skid Indication (red)

When roll command arrow shown:

  • slip/skid indication outline will turn red.
  • slip/skid indication will fill red if it is deflected greater than 25% of its width.

Roll Command Arrow (red)

The roll command arrow points in the shortest direction to wings level. If the bank angle passes 180 degrees, the roll command arrow points in the new shortest direction to wings level. The roll command arrow is displayed with or without the autopilot engaged.

The roll command arrow is shown when bank angle exceeds:

  • 45 degrees if the pitch attitude is 25 degrees or less.
  • 65 degrees if the pitch attitude is greater than 25 degrees.

The roll command arrow is removed:

  • when the bank angle is less than 35 degrees for 2 seconds, or;
  • immediately if the bank angle is less than 10 degrees.
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