10.

Automatic flight system

STL 472.755/92 Issue 4

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A330 automatic flight system

Architecture block diagram
ADR / IR ILS (MLS)
Flight controls Flight controls

FCU
Primary Secondary

ADF ECAM RA VOR DME CLOCK FCMC DATA BASE LOADER

Back-up Nav

FMGC
Maintenance

EFIS CPC
ATSU option
ACARS option

LGCIU
FADECs SFCC
Thrust levers

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A330 automatic flight system

Architecture components
Unit FMGC FCU MCDU A/THR instinctive disconnect switches Number per aircraft 2 1 3 2 Comments FMGEC 1 includes AFS/FIDS* Includes three independent channels Colour display One for CM 1 and one for CM 2

AP take-over switches
North reference switches FM source switch

2
1 1

One for CM 1 and one for CM 2

For EIS and MCDU display For EIS display

* Fault isolation and Detection System OBRM (On-board Replaceable Modules) - Solid-state memory modules plugged into the front face of the computer. - Cost and logistic improvement for software changes. - Software change can be achieved in situ using a common replaceable module reprogrammer.
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A330 automatic flight system

Flight Management Guidance and Envelope System (FMGS) crew interface
SPD MACH HDG TRK LAT HDG V/S TRK FPA ALT LWL/CH V/S FPA

FCU

HDG TRK SPD MACH AP 1

V/S FPA

100

1000 METRIC ALT

UP PUSH TO LEVEL OFF DN

AP 2

LOC

A/THR

ALT

APPR

PFD1
S ED PE G/S L OC CAT2 DH 100 3000 20 10 160 20 015 10 AP 1 1FD2 A/T HR

ND1
GS394TAS 388 249/16

ND2
LWG/004 93MM 18:35

PFD2
LWG/004 93MM 18:35

35 34 33 CGC

2 OL

GS394TAS 388 249/16

3 4

35 34

2 OL

S ED PE

G/S

L OC

3 4
20 10 20

CAT2 DH 100 3000

AP 1 1FD2 A/T HR

180

CON AVD AVD

FMGC 1

FMGC 2

33 CGC

CON AVD AVD

180

015 10 160

13
010

20 00 80

13
010

20 00 80 7

7 10 10

LWG

60

140

60

40

TILT -3,00 VOR2 AVD

LWG

140

120 TN B 109.30 4.7 NM 31

40

TILT -3,00 VOR2 AVD

10 120 TN B 109.30 4.7 NM 31 32 33

10

160

160

790

OM
1020 QNH

2R VOR1 CGCM 103 NM GAI

790

2R VOR1 CGCM 103 NM GAI

OM
1020 QNH 34 3

32

33

34

NAV ACCY UPGRADED

NAV ACCY UPGRADED

FM1

IND

RDY

SPARE

FM2

FM1

IND

RDY

SPARE

FM2

BRT

BRT

DIR F-PLN AIR PORT

PROG RAD NAV

PERF FUEL PRED A F K P U Z

INIT SEC F-PNL B G L Q V C H M R W +

DATA MCDU MENU D I N S X

DWFY

DIR F-PLN AIR PORT

PROG RAD NAV

PERF FUEL PRED A F K P U Z

INIT SEC F-PNL B G L Q V C H M R W +

DATA MCDU MENU D I N S X

DWFY

E J O T Y
CLR M C D U M E N U F A I L F M

E J O T Y
CLR M C D U M E N U

F A I L F M

1 4 7 .

2 5 8

3 6 9

1 4 7 .

2 5 8

MCDU
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Thrust levers

MCDU
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A330 automatic flight system

FMGS - AFS/FMS integration
Composed of two computers (FMGC) including a management part (FM), a flight guidance (FG) and a flight envelope part (FE), this pilot interactive system provides : - flight management for navigation, performance prediction and optimization, navigation radio tuning and information display management, - flight guidance for autopilot commands (to EFCS), flight director command bar inputs and thrust commands (to FADECs) - flight envelope and speed computation. The FMGS offers two types of guidance achievable by AP/FD :

- managed : guidance targets are automatically provided by the FMGS as a function of lateral and vertical flight plan data entered in the Multipurpose Control and Display Units (MCDU).
- selected : guidance targets are selected by the pilot on the glareshield Fight Control Unit (FCU). Selected guidances mode always have priority over the managed guidance modes.
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A330 automatic flight system

FMGS Crew interface
Three MCDUs (only two at a time) on the central pedestal provide a long-term interface between the crew and the FMGCs in terms of : - flight plan definition and display - data insertion (speeds, weights, cruise level, etc.) - selection of specific secondary flight plan). functions (direct to, offset, Two PFDs and two NDs provide visual interface with flight management and guidance-related data such as : on PFD : - FMGS guidance targets - armed and active modes - system engagement status on ND : - flight plan presentation - aircraft position and flight path - navigation items (radio aids, wind).

One FCU on the central glareshield provides a shortterm interface between the crew and the FMGCs. Two thrust levers linked to the FMGCs and FADECs provide autothrust or manual thrust control selection to the crew.

PFD
NAV

ND
GS 394 TAS 388 249/16
35 34 33 ANG 0 1 2 OL CDN

SPEED

ALT CRZ

AP1 1FD2 A/THR

315

LMG/004 93 NM 18:35
3 4

320 10 300 280 10 260

305

10
20 310 00 80

AMB AVD

10

CGC 2'30

LMG

TILT -3,00

780 33 34 35 0

STD

2R GAI

VOR1 CGCM 103 NM

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A330 automatic flight system

General functions
Guidance function Fail operational architecture* Operation Modes Autothrust Operation Modes Flight envelope Envelope protection --------------- (windshear, aft CG detection) Speed computation Flight management Functional architecture Navigation Flight planning functions -------- (assembly , fuel management, lateral revision) Optimisation performance ------ (speed/altitude, prediction) Vertical profile * Fail operational refers to a single failure of a system which does not modify the aircrafts flight path. AP/FD and A/THR mode relationship

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A330 automatic flight system - guidance function

Flight Control Unit (FCU)

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A330 automatic flight system - guidance function

AP/FD modes
Available modes Guidance Lateral Managed mode NAV B/C*, B/C, LOC*, LOC RWY RWY TRK GA TRK ROLL OUT SRS (TO and GA) CLB, DES ALT G/S*, G/S FINAL DES FLARE Selected mode HDG - TRK Mode engagement (or arming as long as engagement conditions are not met). - By pushbutton action (located on the FCU) LOC APPR - ALT, AP1 - AP2 - A/THR. - By action on the thrust levers. On the ground, setting the thrust levers to the TO/GA or FLEX/TO detents leads to AP/FD mode engagement (SRS/RWY). During approach, setting the thrust levers to TO/GA engages go-around mode. OP CLB, OP DES V/S - FPA ALT*, ALT - By action on the FCU selection knobs (speed selection knob, HDG/TRK selection knob, altitude selection knob, V/S-FPA selection knob). Push action engages managed mode Pull action engages selected mode e.g speed or Mach selected mode pushed in flight engages managed speed profile (usually ECON).

Vertical

Speed

FMGC reference FCU reference ECON, Auto SPD, SPD LIM

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A330 automatic flight system - guidance function

AP/FD operation
The aircraft can be operated in selected guidance with flight references selected by the crew, or in managed guidance with references computed by the system. If the AP/FD controls a vertical trajectory the A/THR controls the target SPEED/MACH. If the AP/FD controls a target speed, the A/THR controls the thrust.

Lateral modes
NAV : lateral navigation Lateral track is defined by the FMGC according to the flight plan introduced in the system. LOC : LOC axis capture and track LOC is armed if LOC pushbutton is pressed ; LOC capture replaces NAV. HDG/TRK Selection of HDG/TRK references is obtained by turning the dedicated switch located on the FCU. HDG/TRK is engaged by pulling on lateral selector ; HDG/TRK value can be selected before or after pull action. Heading track preselection is possible on ground before take-off, in flight as from 30 ft height.

Selected guidance always has priority over managed guidance, which means that the PF may select a speed, lateral or vertical path at any time ; actions are acknowledged on the FCU itself and on the FMA (Flight Mode Annunciator).
Selected guidance or managed guidance is available for SPEED/MACH control, LATERAL guidance and LEVEL CHANGE execution.

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A330 automatic flight system - guidance function

Vertical modes
Level changes [managed guidance (CLB, DES), selected guidance (OP CLB OP DES)]. In CLB/DES modes vertical path is maintained as defined by the FMGC, taking into account the flight plan constraints inserted in the system at the clearance altitude selected on the FCU. OP CLB (OP DES) mode allows the aircraft to climb or descend uninterrupted toward FCU selected altitude, maintaining a TARGET SPEED (managed or selected) with a fixed given thrust. ALT constraints are ignored. Altitude hold It is active if aircraft reaches FCU altitude, intermediate flight plan altitude constraints when ALT pushbutton is depressed on FCU or when V/S is set to zero. V/S/FPA V/S/FPA is engaged by pulling on V/S/FPA selector. V/S or FPA value can be selected before or after a pull action. Take-off

Common modes
Approach ILS available - GLIDE capture and track - FLARE - LAND - ROLL OUT ILS not available, RNAV approach selected on MCDU : - LATERAL guidance on the F-PLN - VERTICAL guidance and descent allowed down to MDA. SRS - with engines running V2 + 10 holding - with one engine out VA (1) holding if VA>V2 V2 holding if VA<V2.

(1) VA = aircraft speed when the engine failure occurs.

RWY : - Track hold or LOC centerline hold. Go-around SRS (as take-off). GA TRK hold.

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A330 automatic flight system - autothrust function

AP/FD and A/THR mode relationship
1st case AP/FD pitch mode controls a vertical fligh path (V/S or G/S or FINAL) then A/THR mode will control the target speed/Mach. e.g. if AP/FD V/S mode is selected A/THR is in SPEED mode

S PEED

G/S

LOC

CATII DH= 200

AP1 1 FD2 A/T HR

2nd AP/FD pitch mode controls the target speed/Mach then A/THR mode will control the thrust e.g. if AP/FD open CLB mode is selected A//THR is in THR CLB mode

T CLB OP CLB HR

NAV

AP1 1 FD2 A/T HR

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A330 automatic flight system - autothrust function

AP/FD and A/THR SPD/MACH modes
In SPD/MACH managed mode AP/FD and A/THR SPD/MACH modes SPEED/MACH managed or selected may either be controlled by AP/FD pitch mode or A/THR mode. The reasons for this are as follows. An AP/FD pitch mode may control a flight or an indicated airspeed - but not both at the same time. Thus, if the pitch mode (elevator) controls a flight path, (G/S of V/S) the A/THR controls the IAS, but if the pitch mode controls a speed (OPEN CLB/OPEN DES) then the A/THR will control a thrust. Consequently, AP/FD pitch mode and A/THR are linked so that, if no AP/FD engaged, A/THR can be active in SPD/MACH mode.

Is engaged by pushing the FCU SPD selector knob.

AP/FD or A/THR holds the SPEED/MACH as provided by the FMS. Speed preset for next flight phase is available by entering preset value on the MCDU ; speed preset becomes active at flight phase change. Crossover altitude is automatically provided. SPD/MACH selected mode Is engaged by pulling the FCU SPD selector knob. Crossover altitude is automatically provided. Manual SPD/MACH selection is available to the pilot via the SPD/MACH conversion push-button.

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A330 automatic flight system - autothrust function

A/THR operation - A/THR can be armed, active or de-activated

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A330 automatic flight system - autothrust function

A/THR main features
Each engine thrust is electrically controlled by the associated FADEC (FULL Authority Digital Engine Control) which is fully integrated in the autothrust system. The A/THR function is computed in the FMGC. The FADECs receive A/THR commands directly from the AFS via an ARINC 429 bus.

Selection of thrust limit mode is obtained from the Thrust Lever Angle (TLA).

A / THR ACTIVE RANGE inop engine

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A330 automatic flight system - autothrust function

A/THR mechanisation
The thrust levers can only be moved manually by the pilot. Take-off - to be CLB detent Thrust mode selection - to the MCT detent (engine failure case). - On ground TO limit mode is automatically selected at power up. - FLX/TO limit mode is selected by setting a FLX/TO temperature on the MCDU (TO page). - The A/THR modes become active according to AP/FD mode selection. Approach Thrust levers must be set to CLB (or MCT engine failure case) detent : - ATS SPD mode is active Go Around GA mode engagement is achieved by setting the thrust levers to TO/GA detent ; (A/THR armed ; GA thrust is applied via the FADEC). This maneuvre also engages AP/FD GA mode. Alpha floor If the alpha floor function is activated, A/THR increases the thrust to the GA thrust limit.
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Cruise Thrust levers must be set :

Take-off is performed :
- in limit mode, by manually setting the thrust lever to TO/GA detent. - in FLX/TO limit mode, by manually setting to FLX/TO/MCT detent. Notes : - In both cases, this manoeuvre also engages FD TO mode (SRS RWY if ILS selected). - The lowest FLX/TO thrust is limited to CL thrust.

A330 automatic flight system - autothrust function

Flight envelope protection
Flight envelope protection is achieved by generating maximum and minimum selectable speeds, windshear warning and stall warning. Also computed as part of this protection are the maneuvering speed and the flap and slat retraction speeds. The alpha-floor signal is computed by the flight control computers.

Speed computation (PFD scale)

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A330 automatic flight system - flight management

General architecture
FCU FMGC 1 FE Com FG Com
EFIS CP 1 EFIS CP 2 AP CONTROLS

FMGC 2 FE Com FG Com

Mon
FM

Mon

Mon
FM

Mon

FIDS

MCDU 1 BACK UP NAV MCDU 3

MCDU 2 BACK UP NAV

MCDU 3 switchable for FM function in case of MCDU 1 or 2 failure

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A330 automatic flight system - flight management

Functional architecture - Normal configuration

DMC 1

DMC 3

DMC 2

FMGC1

FMGC 2

MCDU 1
FM NORM BOTH ON 2 BOTH ON 1

MCDU 2

MCDU 3

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A330 automatic flight system - flight management

Functional architecture - One FMGC failed
DMC1 DMC3 DMC2

Functional architecture - Normal configuration

DMC1 DMC3 DMC2

FMGC1

FMGC2

FMGC1

FMGC2

MCDU1 FM NORM BOTH BOTH ON 2 ON 1

MCDU2 FM NORM BOTH BOTH ON 2 ON 1

MCDU1

MCDU2

MCDU3

MCDU3

DMC1

DMC3

DMC2

FMGC1

FMGC2

MCDU1 FM NORM BOTH BOTH ON 2 ON 1

MCDU2 OFF MCDU3 MCDU 2 brightness knob on "OFF"

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A330 automatic flight system - flight management

Two FMGCs associated to two MCDUs provide a redundant configuration Normal mode operation : dual mode - Each FMGC makes its own computation. - One FMGC is master - the other one is slave. - Both FMGCs are synchronized.
MCDU MCDU FMGC 1 crosstalk buses

FMGC 2

- Both MCDUs act independently (entries are automatically transmitted on the other MCDU and applied to both FMGCs). Independent mode - Automatically operative if mismatch occurs between FMGCs. - Independent operation of FMGC with associated MCDUs. (Data insertion and display related to the side concerned. - One FMGC remains master.

FMGC 1

FMGC 2

MCDU FMGC 1

MCDU

MCDU

MCDU

Single mode - One FMGC fails.

- Either MCDU can be used to enter or display data related to the remaining FMGC.
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A330 automatic flight system - flight management

Left intentionally blank

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A330 automatic flight system - flight management

Position indication

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A330 automatic flight system - flight management

MCDU
1 5
10

15

20

25

ECON DES
CRZ OPT

AI101 REC MAX FL390

1L 2L 3L 4L 5L 6L

1R 2R 3R 4R 5R 6R
CGC CDN AVD AVD
60
GS394TAS 388 249/16

REQD DIST TO LAND = 70NM DIR DIST TO DEST = 89NM < REPORT BRG / DIST TO / UPDATE AT VOR 1 / FREQ ACY FREQ / VORZ ATH / 114.4 HIGH 117.2 / DDM

ND
35 34 33 OL 0 1 2
LWG/004 93MM 18:35

3 4

LWG
160
40

TILT -3,00 VOR2 AVD

2R VOR1 CGCM 103 NM GAI

NAV ACCY UPGRADED

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A330 automatic flight system - flight management

Lateral navigation
Position computation - Before flight, the three IRSs are aligned on airfield or gate position (manually or via database). - At take-off, the position is automatically updated to the runway threshold. - In flight, position updating is computed using radio navaids (DME, VOR, ILS and GPS when available). The FMGC position is a blend of IRS and radio position. On a medium-term basis the FM position will tend towards the radio position, if any drift occurs. Navigation mode selection - If the aircraft is equipped with GPS primary, the FMGC uses the GPIRS position in priority (IRS-GPS mode). - if the GPIRS position is not available or if the aircraft is not equipped with GPS primary, depending upon availability of navaids and sensors, FMGC automatically uses the best navigation means to compute the most accurate position : IRS - DME/DME IRS - VOR/DME IRS - ILS/DME IRS only.
STL 472.755/92 Issue 4 10.25

The FMGC position is associated with a high or low criterion which is based on an Estimated Position Error (EPE). This EPE depends upon the flying area (en route, terminal, approach) and is permanently compared to Airworthiness Authorities Accuracy Requirements (AAAR). If EPE > AAAR, then LOW is displayed on MCDU and the position must be cross-checked with raw data (ADF/VOR needles, DME reading). Each time HIGH (or LOW) reverts to LOW (or HIGH) the message NAV ACCUR DOWNGRAD (or UPGRAD) is displayed on NDs and MCDUs.

A330 automatic flight system - flight management

Radio navigation
Each FMGC tunes its own side radio navaids except when in single operation : - one VOR, one ILS, one ADF (if belonging to the F-PLN) and five DMEs may be auto tuned at the same time. - manual tuning always has priority over autotuning. - autotune priority rules are done according to FMGS logics ; for example : VOR autotune (frequency course) priority is :
RMP 1 RMP 2 VOR 2 DME 2 ILS 2 ADF 2

Radio navigation architecture

FMGC 2

RADIO NAV
VOR 1 FREQ SIU / 128.50 CRS 075 ILS / FREQ ( )/( ) CRS ( ) ADFI / FREQ 10E / 415.00 FREQ/ VOR 2 115.70 /TGO CRS ( )

FMGC 1

FREQ/ ADF 2 415.00 / 10E

FMGC 1

FMGC 2

- manual tune - specified navaid for approach - radio position computation - display purpose logic. Five DMEs can be scanned simultaneously - one DMEs for display purpose - two DMEs for radio position computation when in DME/DME mode - one DMEs for VOR/DME position computation when in VOR/DME mode - one DME is linked to ILS/DME.

VOR 1 DME 1 ILS 1 ADF 1

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A330 automatic flight system - flight management

Navigation and flight planning
Navigation Aircraft position determination. Aircraft position referenced to the flight plan. Automatic VOR/DME/ILS/ADF selection. Automatic guidance along flight plan from take-off to approach. IRS alignment. Ground speed and wind computation. Polar navigation. Definition of five cruising levels on the flight plan. Optimum radio and inertial sensor mixing. Extension of the data base capacity. Provision for GPS and MLS. Standard flight plan revision (offset, DIR TO, holding pattern, alternate flight plan activation, etc.). Additional flight plan revisions linked to long-range flights (DIR TO mechanization, AWY stringing). Secondary flight plan creation similar to primary flight plan. Flight plan stringing Flight plan definition by company route or city pair. Departure and arrival procedures including associated speed/altitude/time constraints.

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