B737 Integrated Standby Flight Display

The Integrated Standby Flight Display (ISFD) provides critical flight information, including attitude, airspeed, altitude, localizer/glideslope deviation, and magnetic heading.

ISFD
P2 CENTER INSTRUMENT
  • Attitude is calculated using data from internal inertial sensors.
  • Airspeed and altitude are derived from pneumatic pressure via direct connections to the auxiliary pitot and alternate static sources.
  • Localizer/Glideslope deviation is sourced from the #1 MMR, which supports ILS and GLS inputs.
  • Magnetic heading is supplied by the ADIRU-L but is unavailable in polar regions. In such cases, the ISFD automatically switches to true heading.

Note: The standby magnetic compass must be used to validate the displayed information.

Approach (APP) Switch

  • Push:
    • When blank, selects APP
    • When APP displayed, selects BCRS
    • When BCRS displayed, blanks.

Approach Mode Annunciation

  • Indicates approach mode selected:
    • Blank – no approach deviation data displayed
    • APP – ILS localizer and glideslope deviation data displayed
    • BCRS (Back course) – reverses sensing for localizer pointer during back course approaches.

Attitude Display

  • Displays airplane attitude:
    • Indicates bank in reference to the bank scale
    • Indicates the horizon relative to the airplane symbol
    • Beyond 30 degrees pitch, large red arrowheads (V-shaped) indicate the attitude has become excessive, and the direction to the horizon line.

Display Brightness Switches

  • Push:
    • “+” increases display brightness
    • “–” decreases display brightness.

Airplane Symbol

  • Indicates airplane attitude with reference to the horizon.

Airspeed Indications

  • Indicates current airspeed when above 30 knots.

Attitude Reset (RST) Switch

  • Push and hold at least two seconds:
    • Aligns horizon with the airplane symbol
    • Reset takes approximately ten seconds
    • Starts new initialization sequence if previous attempt failed (ground only).

Hectopascal/Inch (HP/IN) Switch

  • Push: changes the units of the barometric reference.

Barometric Setting

  • Indicates the barometric setting selected with the barometric selector:
    • STD is displayed when selected with the barometric selector.

Ambient Light Sensor

  • Automatically adjusts display intensity for ambient lighting condition.

Glideslope Pointer and Deviation Scale

  • The glideslope pointer indicates glideslope position relative to the airplane:
    • The pointer is in view when the glideslope signal is received
    • The scale is in view when the APP mode is selected
    • The pointer and scale are removed when the BCRS mode is selected.

Current Altitude

  • Displays current altitude.

Localizer Pointer and Deviation Scale

  • The localizer pointer indicates localizer position relative to the airplane:
    • The pointer is in view when the localizer signal is received
    • The scale is in view when either the APP or BCRS mode is selected.

Barometric (BARO) Selector

  • Rotate: changes barometric setting
  • Push:
    • Selects standard barometric setting (29.92 inches Hg/1013 HPA)
    • If STD is displayed, selects the preselected barometric setting.

Heading Indication

  • Displays airplane heading.