Flight Director Systems (FDS) and Display Units

• Flight Director Systems (FDS) or Integrated Flight System (IFS) integrates signal inputs to provide output to a display system.
• Inputs include attitude reference, heading, VOR, localizer, glide-slope, marker, radio altimeter, INS, Doppler, DME, RNAV/VNAV, and speed control signal information.

Display Units

• A flight director system has two principal display units:
• Attitude direction indicator, flight director, or approach horizon
• Horizontal situation indicator or course deviation indicator

Attitude Director Indicator

• Represents view from behind the aircraft, displaying steering command and aircraft attitude around a fixed symbol.
• An aircraft symbol is in the display center, adjustable via a knob.

Attitude Sphere

• A blue and brown sphere with a white line (horizon), with a pitch ladder to show climb/dive angles (0-90°).
• It's free to move 360° in the roll axis and 90-360° in pitch axis.

Bank Pointer

• Displays the bank angle against a scale.

Command Bars

• Two command bars exist, one for pitch and one for roll, the pilot flies the aircraft symbol towards the command bars according to commands from the Flight Director Computer (FDC).

Glideslope Pointer

• On the ADI's left, shows the aircraft's vertical position relative to glideslope beams during landing.
• When centered, the aircraft is on the glideslope, if the glideslope pointer is on the dot closest to the centre line, the pitch command bar comes into view with direction.

Localiser Deviation Indicator

• Shows the aircraft's position relative to localizer beams, aircraft is centered in the beams when the pointer is in the scaler.

Slip and Skid Indicator

• Shows the type of turn.

Rate of Turn Indicator

• Shows how fast the aircraft is turning.

Off Flag

• Indicates power loss or incorrect phase rotation.

Course Warning Flag

• Appears when bank steering information is unreliable.

Glideslope Flag

• Indicates that ILS signal loss when FDS is in ILS mode.

Attitude Directors Operation

• Flight director indicator mimics a gyro horizon, but pitch and roll are electrically controlled from a remote vertical gyro unit.
• Electrical signals flow from pitch and roll synchros when aircraft attitude changes, inducing error signals in rotors.
• Servomotors then position the pitch bar and horizon disc/sphere/cylinder to reflect the changing attitude.
• The servomotors drive the synchro rotors to the 'null' position.

ILS Interconnection

• During ILS approach, the receiver detects ground transmitter signals in vertical and horizontal planes.
• The meter controlling the glide slope pointer deflects the pointer downwards if the aircraft is above the glide path.
• The meter moves the pointer upwards if the aircraft is below the glide path, directing the pilot to correct vertical position.

Localizer Beam Deflections

• If the aircraft is to the left of the localizer beam and runway centerline, the localizer pointer deflects to the right.
• The pilot banks right and vice versa, until the pointer is centered vertically on the horizon disc.

Synchro/Servo Devices

• The flight director indicator houses multiple servo/synchro devices; pitch and roll information from a twin gyro platform positions horizon disc and pitch bar.
• The additional devices drive command bars based on signals from the flight director computer.
• The Attitude Director Indicator (ADI) contains synchro/servo devices and servo motors, commanded by the flight director computer.

Horizontal Situation Indicator (HSI)

• Displays the aircraft's flight navigational situation, using a miniature aircraft symbol to show position relative to radio beams and presents heading information on an azimuth card.

Aircraft Symbol

• Represents the aircraft's view from above, mounted in the HSI dial center.

Compass Card

• Located around the aircraft symbol, displays the aircraft's heading.

Upper Lubber Line

• A reference line for accurate heading, positioned over the compass card.

Lower Lubber Line

• Extension of the upper line at the dial's lower part.

Deviation Section

• Rotates with the compass card, adjustable via the course set knob.

Course Arrow

• Indicates selected course rotation of course set knob rotates, error signal produced, repositions CDI bar.

Course Arrow Tail

• An extension of the course arrow, located on the opposite side, but in line with the course arrow.

Course Deviation Indicator (CDI)

• Provides visual indication of deviation from selected course.
• If the CDI bar is displaced to the left of the course arrow; the aircraft is flying to the right and vice versa unless the CDI bar is centred.
• The CDI bar displays deviation relative to four dots, closest is five degrees of deviation whilst outermost dots are ten degrees in VOR.

TO/FROM Indicator

• With VOR frequencies active, indicates the station's direction along selected course.
• 'TO' is displayed the white triangle is near the head of the course arrow (within 90° of each other.)
• 'FROM' is shown is white triangle is near the tail (within 90° of each other.)

Heading Marker

• Rectangular marker with a black centerline, located on the compass card's edge, positioned by the set knob to indicate desired heading.
• Rotation sends an error signal to the CDI and ADI bank steering bar, used to return to the selected heading.

Bearing Pointer

• An arrowhead indicates bearing to a radio navigation aid.

Course Selector Window

• A repeater of the course arrow setting located at the top right.

Range Indicator

• A counter display located at the top left displays the slant range to the radio navigation aid.

Course Set Knob

• Located at the bottom right, to make course selections.

OFF Flag

• The right side of the indicator indicates AC power failure or incorrect phase rotation.

Range Failure Flag

• Covers the range counters (top left), and displays when range signal loss from the radio navigation aid.

TO/FROM Warning Flag

• Covers the to/from indicator and is displayed when the aircraft has not locked onto the radio navigation aid.

Horizontal Situation Indicators Operation

• Shows magnetic heading, radio bearing, and localizer information against a fixed aircraft symbol, providing a plan view.
• A compass card is monitored by directional gyro unit signals and indicates magnetic heading.
• Localizer and glideslope elements function similarly to flight director indicator.
• The lateral deviation bar can rotate with the compass card as heading changes.
• Arrow indicates flight direction (to/from VOR station), positioned by a meter.
• Course select and heading knobs select localizer/VOR radial and magnetic heading.

FDS Operating Modes

• OFF: Command bars are hidden; flight director indicator only shows attitude.
• HDG: Command bars provide lateral guidance to a compass heading.
• NAV/LOC: Command bars provide lateral guidance to capture and track a VOR radial or localiser beam
• ALTITUDE HOLD: Command bars provide vertical guidance to hold altitude
• APPR MAN: For Category I ILS approaches, command bars provide lateral and vertical guidance and is known as glideslope
• APPR AUTO: Like APPR MAN, but tighter tracking for Category II ILS approaches, also known as GS Auto.
• GA: Selected for a go-around, command bars command wings-level, pitch-up attitude.
• Modes - HDG and IAS selected after go-around power settings and airspeed are established.

Key Operational Points

• OFF: Command bars receive no signals and hide.
• FDI supplied aircraft attitude and HSI shows heading information.

Heading (HDG) mode

• Pilots select the heading.
• ADI and HSI indicate the aircraft flying straight and level on heading of 000° and the HSI heading marker is positioned under the lubber lined
• ADI bank steer bar is centered.

Selected heading.

• To fly the aircraft on a selected heading, the pilot positions the heading marker over the desired heading with the heading knob.
• If the aircraft's actual heading isn't the desired heading, an error signal is made by differential synchros within the HSI, and are supplied to the flight director computer that combines with bank bangle
• The aircraft banks to change heading and positions the bank steering bar on the ADI is used.
• After the aircraft the aircraft arrives at the bank steering bar it will maintain the selected heading

Approach - ILS Mode

• Depends on two radio beams to inform the aircraft's position relative to the runway

Localiser Course

• The pilot sets the selected localiser course via the HSI with the intention of positioning an arrow on the appropriate heading.
• When indicated the set course will be on the HSI by comparing with the compass card
• If the aircraft isn't correctly positioned a course error will develop via differential synchros in the HSI
• Then the error signal will be sent to the computer to be combined into lateral steering information to the ADI.
• This creates a command for the pilot to turn towards the fixed bank steering bar
• Maintaining will ensure the aircraft remains on centre to the localiser beam.

Glideslope Function

• When glideslope pointer comes at the top of the glideslope scale the pilot can position the aircraft respective to the glide slope pointer
• When positioned correctly can determine the relation to the end of the runway
• An error of one pointers worth indicates the pitch steering bar is active

Altitude Hold Operation

• The operation of the flight is controlled from the Central Air Computer
• There is a reference to the real time position of the aircraft to the CADC
• Any error is used to drive the pitch command bar

Pitch vs Steering Bar

• The computer will process the parameters to control the director / steering bar
• Inputs from the twin gyro or FDI are interfaced from the FDC

Flight Director Computer Operation

• The outputs are interfaced with ADI indicator from FDC
• The FDC also needs know of the currect attitude / starting position
• When steering the aircraft this command will be removed

Signal Inputs

• Flight computer will process all inputs
• As well as pilots selection i.e altitude / heading

The signal source (Pitch Channel)

• The vertical gyro that provide FDS with aircraft pitch
• Central Air Data Computer (CADC) (Barometric Presure)
• Radar Altimeter ( above the ground height)
• Instrument landing system (glide slope)

What's determined

• Determine that signal has used a ptich signal to determine source information Roll CHannel
• Vertical gyro
• Instrument lending system
• Compass information

Signal Source (Roll Channel)

• The Vertical gyro that provides aircraft roll
• The instruments that provides localisation
• DME
• VOR
• Compass system

How it works

• As in conventional flight directior system
• A pilot will operate the Left (Captain) and right (First Officer) systems
• Each system is a comprised of -EADI and an EHSI, a control panel, a Symbol Generator (SG), and a remote light sensor unit.
• A third SG can be installed (centre), so if any display system fails can be switched across
• Acconplished within the left and right SG's The system runs via the air crafts DC power supply that will switch the electro mechanical relays

Digital data bus

• Use memory based micro processors
• Multi Function Display (MFDs) or Digital Display Indicators (DDIs). through digital data

Typical install

• displays are in front of the pilot
• CRTs mounted between the pilots are typically dedicated to providing EICAS or ECAM information.

Data Bus Tech Upgrade

• Better displays like Large uncluttered displays, 8 x 10 or 10 x 12 enhance crew efficiency and situational awareness.

• Types PFD, MFD or EICAS display

Multi Use Formats

• Primary Flight Indicator attitude, airspeed, vertical speed
• Multi fuction navigation maps, radar and maintinace data

Operation

• ECIAS (system display)
• Electronic ADI traditional pitch and roll, flight

Electronic ADI

• flight director commands, ILS localiser / glide slope deviations
• automatic flight control and auto- throttle modes
• is concerned, the unit is one utilising inertial references.

Sky Terrain

• The coloured that represent the the sky ( Cyan) as denoted by a raster scan
• The terms are when the electron that are generated by the cathode will deflect - solid image
• Then the other symbols ( stroke pulse)
• All of the scanning will be done by the symbol generator

Radio Alteration Note

• If aircraft is 2500 / 1000 feet the display will change
• below 100 foot display changes to white circular scale
• -erasing anticlockwise

Aural Notication

• Before height select pilot will get aural warning

Operation

• the amount generated will generate air The HSI provides a dynamic view / display of the flight The mode selection panel comes in varieties Map, Plan , ILS , VOR Map Mode is set as standard for colour identification

Display and Integration

• Computer will inter grate flight plan
• Symbals and location of the flight
• A common scale and heading

Electronic HSI Displayed Data

• Stations
• Airports and identicication
• Selected weather patern

Different Electronic HSI display's

• Various displays such as ILS, VOR and Plans
• The main feature of the plan display is the static view so that you can update information quickly Then VOR and HSI modes show expanded range, wind and name