Boeing 737 ND Failure Flags and Messages

The Boeing 737 NDs provide a mode–selectable color flight progress display. The modes are: MAP, VOR, APP (approach), and PLN (plan). ND provides the following information:

• Heading
• Track
• Traffic information from the TCAS
• Weather Radar Information
• Failure Flags and Messages

Failure flags are displayed for system failures or invalid information. Indications are blanked or replaced by dashes when source system information is not available.

RAAS Alerts

Runway Awareness and Advisory System Alerts (RAAS)

• ON TAXIWAY (amber)
  • Appears each time the airplane:
    • is on a surface other than a runway, and
    • ground speed is greater than 40 knots
• SHORT RUNWAY (amber)
  • Appears each time the airplane:
    • approaches within three nautical miles of a runway threshold with available runway length for takeoff less than the defined length required, and
    • is within 20 degrees of the runway heading, and
    • is within approximately 200 feet plus one runway width of the runway extended centerline, and
    • is between 450 feet and 300 feet above field elevation.

Excess Data Annunciation (amber)

The amount of map information sent to the primary display system is too great to display. When this occurs, the system removes some information from the display. The message can be cleared by:

• decluttering – removing unnecessary navigation information.
• reducing the display range.
• deselecting one or more of the EFIS MAP switches (STA, WPT, ARPT, DATA, POS).

Range Disagreement Annunciations (amber)

• MAP RANGE DISAGREE – Indicates selected range on the EFIS control panel is different than the MAP display range.
• WXR RANGE DISAGREE – Indicates selected range on the EFIS control panel is different than the WXR display range.
• MAP/WXR RANGE DISAGREE – Indicates selected range on the EFIS control panel is different than the MAP and WXR display ranges.

Nav Advisory Message (amber)

• UNABLE REQD NAV PERF– RNP – Displayed in MAP modes when FMC actual navigation performance is not sufficient for the displayed RNP. Refer to Chapter 11, Section 60, FMC Messages.

EFIS MODE/NAV FREQ DISAGREE (amber)

The ILS or VOR source annunciation corresponds to the position selected on the EFIS control panel and the tuned VOR/ILS frequency. The annunciation is displayed:

• if APP is selected with a VOR frequency tuned
• if VOR is selected with an ILS frequency tuned.

The DME display and ILS/VOR frequency at the upper right corner display dashes.
The localizer deviation bar, VOR course deviation bar, and glideslope pointer are not displayed.
The annunciation is displayed in the expanded APP, center APP, expanded VOR, and center VOR modes.

TCAS Messages

• TCAS Traffic Symbols
  • Indicates position of traffic targets.
  • Displayed in expanded MAP, center MAP, expanded APP and expanded VOR modes and TFC is selected on the EFIS control panel.
• TCAS Annunciations
  • TFC (cyan) – Indicates TFC selected on EFIS control panel in expanded MAP, center MAP, expanded APP and expanded VOR.
  • TCAS TEST (cyan) – TCAS in test mode.
  • TA ONLY (cyan) – TCAS TA mode only.
  • TCAS OFF (amber) – TCAS off.
• Offscale (red or amber)
  • TA (amber) or RA (red) is beyond the selected display range and TFC is selected on the EFIS control panel.
• Traffic (red or amber)
  • Displayed during a TA (amber) or RA (red) condition whether or not TFC is selected on the EFIS control panel.
  • Shows in all navigation display modes.
• No–Bearing Messages (red or amber)
  • Textual description of TA (amber) or RA (red) traffic with no associated bearing.
  • Message provides traffic type, range in NM, altitude and a vertical motion arrow.
  • A maximum of two messages can be displayed simultaneously.
  • TFC selected on the EFIS control panel.

Look-Ahead Terrain Messages (GPWS)

• Terrain Status Annunciation (amber)
  • TERR FAIL – Look-ahead terrain alerting and display have failed.
  • TERR POS – Look-ahead terrain alerting and display unavailable due to position uncertainty.
  • TERR INHIBIT – GPWS terrain inhibit switch in TERR INHIBIT position.
• Terrain Mode Annunciation (cyan)
  • TERR – Terrain display enabled (manual or automatic display).
  • TERR TEST – GPWS is operating in self-test mode.
• Terrain Range Status Annunciation (amber)
  • TERR RANGE DISAGREE –
    • terrain display enabled, and
    • terrain output range disagrees with selected EFIS control panel range.
  • MAP/TERR RANGE DISAGREE –
    • terrain display enabled, and
    • terrain output range disagrees with selected EFIS control panel range, and
    • map display output range disagrees with selected EFIS control panel range.

Predictive Windshear System (PWS) Message

• PWS FAIL Annunciation (amber)
  • Predictive windshear alerting and display have failed.