Flight Director Group

The flight director group provides the pilot with all necessary instruments to fly the aircraft even in a bad weather situation. It contains the Radar Altimeter (1), the Airspeed and Mach Indicator (2), the Reference System Selector Switch (3), the Attitude Director Indicator (4), the Marker Beacon Lamp (5), the Barometric Altimeter ( 6), the Angle of Attack Indicator (7), the Horizontal Situation Indicator ( 8), the Vertical Velocity Indicator (9), the Standby Attitude Indicator ( 10) and the Navigation Function Selector Panel (11).

Radar Altimeter

Terrain relative accurate height information up to 5000 ft, functions to 30 degrees of bank angle or 35 degrees of pitch. Clockwise rotation of the function control switch (1) on the lower left of the indicator powers the device; continued rotation sets the low altitude warning pointer to the desired height. Below the set altitude, the warning light (2) on the lower right activates. A self-test, initiated by pressing the function control switch, shows 35ft.

Airspeed and Mach Indicator

The combination airspeed and mach number indicator shows airspeed readings below 200 knots, and include Mach numbers on the outer ring at high speed. The indicator uses a single pointer over a fixed airspeed scale, marked from 80 to 850 knots, with a moving Mach scale (2) presenting from Mach 0.4 to 2.5. A pair of movable reference markers is available with the knob (4) on the face of the gauge, with speed reference available between 80 and 195 knots, and the Mach index pointer being able to be set between the 225 knot and 850 knot regions relative to the airspeed gauge. The ( 1) needle and the inner ring refers to the airspeed in knots. The (2) needle and the respective outer ring refers to the Mach scale. Both move along dynamically according to the Airspeed. The (3) area refers to the airspeed scale before the mach scale starts.

Angle of Attack Indicator

Drawing relative wind information from the landing-gear adjacent AoA probe, the AoA indicator offers conditional reference for cruise (7.9 units), approach (19.2 units), and stall (30 units). Because of the AoA probe to the nose gear door and subsequent airflow disturbance when the gear is lowered, actual aircraft AoA is approximately 1 unit higher than indicated, and ON SPEED AoA is roughly 5 knots slower than the given value.

When indicator power is offline due to electrical system configuration or damage, an OFF flag will appear in the window on the face of the gauge. The AoA indicator contains switches that light the indexer lights and actuate the stall warning vibrator.

Reference System Selector Switch

Toggles between the inertial navigation set and AN/AJB-7 displacement gyroscope for attitude information. When set to PRIM, the inertial navigation set provides azimuth and attitude data to the ADI; when on STBY, AN/AJB-7 supplies this information. Azimuth data also feeds into the HSI and BDHI (rear cockpit). Additionally, attitude details are sent to the fire control system.

💡 Inertial information requires the inertial navigator control panel's switch to be on NAV.

When transitioning between STBY and PRIM, immediate attitude information may show unusual gyrations on the attitude director indicator due to initial erection. Rapid turns (above 15° per minute) may temporarily disrupt accurate heading information and automatic synchronization of heading information. If the heading information doesn't resync itself after flying straight and level again for approximately 20 seconds a manual synchronization is required. This can be done by flying in a straight and level flight for about 20 seconds and turning the Mode Selector Knob to the spring-loaded SYNC position for approximately 3 seconds.

Attitude Director Indicator

Includes an attitude sphere, turn indicator, steering bars, miniature aircraft, glide-slope pointer, flags, and pitch trim knob. It displays pitch, bank, and heading from the selected reference system and allows pitch adjustment via the trim knob. The turn indicator relies on a gyro from the AN/AJB-7 system. The steering bars offer Flight Director guidance for heading interception, navigation, and ILS approaches. The glide-slope pointer provides vertical guidance information during an ILS approach.

Marker Beacon Lamp

This lamp illuminates whenever flying over a marker beacon station, provided the VOR/ILS system has been activated. Additionally, an audio cue is played through the intercom system.

The lamp can be rotated to dim and pushed to test.

Horizontal Situation Indicator

Presents a horizontal view of the navigation situation relative to the aircraft, indicated by an aircraft symbol and a lubber line showing the current aircraft heading.

Knobs

The knob on the lower left (1) is available to input desired magnetic heading, and the Course Set knob (4) on the lower right is used to enter VOR radial or inbound localizer course for accurate deviation display.

Compass Card

A rotating element (5), dependent on the AJB-7 heading input, displays a compass rose.

It provides a reference for the aircraft's heading relative to magnetic north.

Bearing Pointer

Indicates the magnetic bearing to a selected navigation aid (Nav Comp, VOR, TACAN, or ADF).

Course Arrow and Deviation Indicator

The direction towards which the arrow (6) points can be manually selected by the Course Knob in VOR/ILS and TAC modes (as seen on course rollers).

In HDG mode, it indicates the aircraft's magnetic heading, and in NAV COMP mode, it points to the aircraft's magnetic ground track.

The Deviation Indicator provides visual feedback on the aircraft's deviation from the selected course. It shows deviation from a TACAN course in TAC mode or deviation from a VOR radial in VOR/ILS mode when VOR is tuned, and deviation from an ILS localizer signal in VOR/ILS mode when ILS is tuned.

To-From Indicator

Reveals whether the current course will lead towards or away from the tuned station, functioning with TACAN and VOR inputs.

Heading Marker

The heading marker (3) can be manually set to the desired heading to provide the Flight Director with steering signals in all modes except NAV COMP.

In NAV COMP mode, it displays command steering towards the selected target, taking wind drift into account.

Range Indicator

Shows the distance (2) to the selected TACAN station or NAV COMP destination.

Mode Indicator Lights

Several lights (7) indicate the active navigation mode:

• VOR: Indicates that the VOR/ILS mode is selected and a VOR frequency selected.
• ILS: Indicates that the VOR/ILS mode is selected and an ILS frequency selected.
• TAC: Shows that TACAN mode is active.
• NAV: Illuminates when the Navigation Computer mode is in use.
• MAN: Indicates that the Heading Mode is selected.
• UHF: Signifies that the ADF mode is active.
• TGT: Illuminates during specific radar offset bombing operations.

Altimeter

A counter-pointer style altimeter, with thousandths in the counter window (4) and 100 foot increments around the face (5). The altimeter has an absolute range of 80,000 feet. The altimeter includes a barometric scale (3) for setting local pressure with the knob (1) on the indicator. Works in either electric (normal operation mode) or pneumatic (STBY) mode, switchable via a spring-loaded three position switch (2) labelled RESET and STBY. When held in RESET for more than 3 seconds the system will be reset and moved out of STBY.

Vertical Velocity Indicator

Provides rate of climb or descent via the static pressure system referenced in thousands of feet per minute.

Standby Attitude Indicator

The SAI functions independent of the Flight Director Group, providing reasonably accurate readings (within six degrees) for 9 minutes if power to the system is lost and the OFF flag is in view. Pitch markings are indicated every 5 degrees, while roll markings are in gradations of 10 degrees. Roll is illustrated through 360 degrees, while pitch is limited by stops at 92 degrees in climb and 78 degrees in dive to prevent gimbal lock. The SAI can be unlocked by pressing the knob and trimmed by turning it.

Navigation Function Selector Panel

Controls display presentation on the ADI and HDI based on the selected values on the two knobs; to the left is the Bearing/Distance Knob (1), and to the right the Mode Selector Knob (2 and 3). The Bearing/Distance Knob determines the source of navigation information for the HSI and ADI. The Mode Selector Knob provides control over the presentation of various displayed information on the HSI and ADI. The Mode Selector Knob includes an inset switch marked FD, for Flight Director. This switch engages or deactivates the pitch and bank steering bars on the ADI; the OFF position has the switch aligned vertically.

Bearing/Distance Knob

Mode Selector Knob Display Functions

VOR Lamp

Illuminates to indicate that the VOR system is ready and receiving.

That is, a valid VOR frequency has been selected, a signal is received and the navigation knobs have been turned to VOR navigation.