Standby Flight Display (SFD)

The Standby Flight Display (SFD) is a small self-contained instrument that keeps working when everything else is dark. It has its own power switch and runs from the emergency DC bus, independent of the AVP and the MFDs.

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1. EW REC - Lit while the EW system tracks a red threat: sim traffic within 5 NM and 1,000 ft of you, moving faster than 20 kt.
2. SFD - Standby flight display: own attitude sensors, airspeed, altitude, heading and Mach, and its own baro knob. Runs on emergency DC, independent of the MFDs.
3. EW RPT - Flashes while EW CONT in RPT is jamming a red threat; REC stays lit with it.
4. ROLL SYNC - Shows the load on the autopilot roll servo; centred with the autopilot off. Off centre in cruise points to a heavy wing.
5. PITCH SYNC - Shows the load on the autopilot pitch servo; centred with the autopilot off. Off centre with PITCH TRIM in MANUAL: trim until it centres.
6. EW CONT - OFF / REC / RPT. REC detects threats (sim traffic stands in for them); RPT adds jamming. A startup self-test runs first (tooltip REC - SBIT). While it is OFF (or unpowered) with the AVP up, EW NO RESPONSE shows. The STAT/FAULT EW BIT takes about 30 seconds (EWS IBIT IN PROGRESS on the EW page).
7. SFD NAV - Cycles OFF / ILS / BC: localizer and glideslope bars from NAV 1. Together with TEST it starts the SFD built-in test.
8. SFD TEST - Built-in test below 60 kt: hold NAV (mouse: click NAV), then press TEST twice within 2 s. On its own it does nothing.

What It Shows

• Attitude ball with pitch ladder and roll pointer.
• Airspeed tape (left, from 60 knots - the higher speeds are at the bottom), altitude tape (right), heading tape.
• Mach number top-left (M.720, shown from Mach 0.30 - blank below) and barometric setting top-right (29.92 IN or STD; while the PFDs are switched to hPa, the SFD's own setting in hPa, without a unit - for example 1013).
• A red band on the speed tape marking your current maximum speed (see below), and with the EFB option Stall speed tape on a yellow band up to the stall speed.
• ILS bars from NAV 1, chosen with the NAV button: ILS shows the localizer and glideslope bars, BC the localizer bar only. With no signal, red LOC and G/S flags take their place. The glideslope bar runs behind the altitude readout box, so on the glidepath (within about 0.2°) you will not see it.
• Below 10,000 ft a green hatched box takes the place of the ten-thousands digit of the altitude readout.

Example SFD flight

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1. Mach number
2. Baro setting (STD)
3. Airspeed tape
4. Airspeed readout
5. Red max-speed band
6. Altitude tape
7. Altitude readout
8. Pitch ladder
9. Roll pointer
10. Heading tape

Example SFD climb

Power-Up

1. Battery on, then SFD switch (right console) ON.
2. A 6-second power-on test runs: white screen, color bars, grid, then an SFD POWER ON BIT list.
3. The attitude area then turns sky blue with the roll scale and the aircraft symbol, but no horizon or pitch ladder yet: ATTITUDE INITIALIZING inside the roll scale and the seconds left under the symbol (10 SECS), for 10 seconds (or 180 seconds with the EFB option Avionics startup time on Realistic). Speed, altitude and heading are usable straight away.
4. Do not move the aircraft. Any movement restarts the count - also after takeoff, where it would never finish (see below).

Example SFD powerup bars

Example SFD powerup grid

Example SFD powerup

Example SFD align

The SFD has its own motion sensors, so its attitude depends only on SFD power and its own initialization - it does not need the INS. What happens after a power interruption depends on how long it lasted and whether you are flying (60 knots or more, or airborne):

Example SFD airalign

An initialization still running when you start to roll never finishes. Switch the SFD off and on again once you are flying (60 knots or more) and it becomes an airborne alignment instead. If your flight starts with the engine running (runway or air start), or after an EFB Set up aircraft preset, the SFD is ready immediately.

Controls

Example SFD approach

Example SFD nav bc

Example SFD nav noils

Example SFD ibit1

Example SFD ibit2

Example SFD ibit3

The Red Max-Speed Band

The U-2's speed limit changes with altitude and with the gust-control setting. The red band always starts at your current limit, and the speed readout turns red when you exceed it. The PFD uses the same limits. The SFD works its band and its red Mach limit out from its own altitude, so they follow the SFD baro setting.

Example SFD maxspeed

Example SFD overspeed

The lower of the two limits applies.

Related pages: Primary Flight Display (PFD) · Electrical and Avionics Power