MCDU / FMGS

Question 1

MCDU / FMGS

Q:​ What are​ the​ main components of​ the​ FMGS?​ ​

Answer 1

Ref: (FOM VOL. III-DSC-22-10-10)​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

• 2​ FMGCs​ ​
• 2 MCDUs​ ​
• 1 FCU​ (two independent channels) ​
• 2​ FACs​

Question 2

MCDU / FMGS

Q:​ What are​ the​ functions of​ the​ Flight Management Guidance​ Computers?​ ​

Answer 2

Ref: (FOM VOL. III-DSC-22-10-10)​ ​

• Flight​ Guidance ​
• Flight​ Management​

Question 3

MCDU / FMGS

Q:​ What are​ the​ 3 modes​ of​ FMGC operation?​ ​

Answer 3

Ref: (FOM VOL. III-DSC-22-10-30)​ ​

• Independent (MCDU scratchpad displays –​ INDEPENDENT OPERATION)​ ​
• Single​ (ND displays​ - SELECT​ OFFSIDE​ RNG/MODE) ​
• Dual​ (Normal)

Question 4

MCDU / FMGS

Q:​ What are​ the​ 2 modes​ of​ flight guidance?​ ​

Answer 4

Ref: (FOM VOL. III-DSC-22-30-10)​ ​

• Managed​ Guidance ​
• Selected​ Guidance

Question 5

MCDU / FMGS

Q:​ What is​ the​ Managed​ mode​ of​ flight guidance​ used for?​ ​

Answer 5

Ref: (FOM VOL. III-DSC-22-30-10)​ ​

Long-term Lateral,​ vertical,​ and speed profiles​ as determined by​ the​ FMGS

Question 6

MCDU / FMGS

Q:​ What is​ the​ Selected mode​ of​ flight guidance​ used for?​ ​

Answer 6

Ref: (FOM VOL. III-DSC-22-30-10)​ ​

Temporary​ lateral, vertical​ and speed commands​ as​ selected​ with the​ FCU

Question 7

MCDU / FMGS

Q:​ Does Selected or​ Managed Guidance​ have priority?​ ​

Answer 7

Ref: (FOM VOL. III-DSC-22-10-10)​ ​

Selected Guidance​ always​ has priority

Question 8

MCDU / FMGS

Q:​ How do you determine the​ validity​ of the​ navigation​ database?​ ​

Answer 8

Ref: (FOM VOL. III-DSC-22-20-20-50) ​

On the​ Aircraft Status​ page​ via the​ MCDU

Question 9

MCDU / FMGS

Q:​ What input does each FMGC use​ for position determination?​ ​

Answer 9

Ref: (FOM VOL. III-DSC-22-20-20-10) ​

A hybrid​ (“mix”)​ IRS/GPS​ position

Question 10

MCDU / FMGS

Q:​ How does​ autopilot selection influence master​ FMGS​ logic?​ ​

Answer 10

Ref: (FOM VOL. III-DSC-22-10-30)​ ​

• If​ one​ autopilot is engaged, the​ respective FMGS​ is​ master ​
• If​ both​ autopilots​ are​ engaged,​ FMGS​ 1​ will be​ the​ master

Question 11

MCDU / FMGS

Q:​ If​ an​ amber​ SELECT OFFSIDE RNG/MODE message​ is displayed on the​ ND what​ action should the​ crew ​take? ​

Answer 11

Ref: (FOM VOL. III-DSC-22-10- 30)

An FMGS​ has​ failed and both NDs​ must be​ set​ to the​ same​ mode​ and range​ (single​ mode)​

Question 12

MCDU / FMGS

Q:​ Can both autopilots be​ engaged during​ any phase​ of​ flight?​ ​

Answer 12

Ref: (FOM VOL. III-DSC-22-30-30)​ ​

No, only​ during an ILS approach

Question 13

MCDU / FMGS

Q:​ What is​ the​ difference​ between the​ large​ and small​ fonts​ utilized in the​ MCDU?​ ​

Answer 13

Ref: (FOM VOL. III-DSC-22-10-40-10) ​

• Large​ –​ Pilot entries​ and​ modifiable​ data​ ​
• Small​ –​ Default/computed non-modifiable​ data

Question 14

MCDU / FMGS

Q:​ When would a Takeoff​ Shift be​ entered on​ the​ PERF​ TO page?​ ​

Answer 14

Ref: (FOM VOL. III-DSC-22-20-20-10) ​

When takeoff​ begins​ at a runway​ intersection and​ GPS is​ not​ primary

Question 15

MCDU / FMGS

Q:​ Where​ do you enter the​ Zero Fuel Weight?​ ​

Answer 15

Ref: (FOM VOL. III-DSC-22-20-50-10-25) ​

INIT B page​ (not accessible​ after​ engine​ start)​

Question 16

MCDU / FMGS

Q:​ What do amber box​ prompts on the​ MCDU​ indicate?​ ​

Answer 16

Ref: (FOM VOL. III-DSC-22-10-40-10) ​

An entry​ is​ mandatory

Question 17

MCDU / FMGS

Q:​ What occurs​ when managed NAV mode​ is​ engaged​ and​ the​ aircraft flies into a flight plan ​discontinuity? ​

Answer 17

Ref: (FOM VOL. III-DSC-22-20-30- 10-05)​ ​

NAV mode​ will be​ lost and​ the​ HDG/TRK mode​ engages​