Autoflight

Question 1

FMS computers and systems?

DUAL FMC mode?

Answer 1

Normally:
FMC-A feeds FMS 1
FMC-B feeds FMS 2
FMC-C standby

Only 1 is master which sends Long-term guidance to FG
But they both independently calculate data which is then compared - DUAL mode

Question 2

1 FMC fails?

Answer 2

Back-up synchronizes with active FMC and replaces faulty one

No major changes other than ECAM to tell us

Question 3

2 FMC fail?

Answer 3

Crew uses FMS switching knob to drive both sides off 1 FMS - FMS SINGLE mode

Question 4

ALL FMS fail?

Answer 4

All FMS data and functions lost both sides

Backup Traj activated allowing crews to manually select navaids and plan basic routing via ISIS

Question 5

Overall AFS architecture?

Answer 5

3 FMCs (A-C) control 2 FMS (1 and 2): (Works out where to go and how to get there)
Flight planning
Nav
Perf computation/optimization
Information display

3 PRIMs: (Provides commands to get there safely)
Flight guidance (AP, AT, FD)
Flight Envelope
Flight control functions

One PRIM is master the other 2 slaves (based on which has best operational capability). If master degrades, SLAVE 1 becomes Master automatically

Question 6

FDs - where is data from and how computed

Answer 6

FD1 - data from ADIRS1, computed by FMS1
2s together

Question 7

ADIRUs

Answer 7

3, each comprised of ADR and IRS

IRS part received GPS data from MMR (receive GPS data from satellites/ground stations + ILS) to realign and compute GPIRS position

ADIRU 1 supplies CM1
ADIUR 2 supplies CM2
ADIRU 3 standby

Question 8

ADR probes?

Answer 8

3 of each for the ADIRS:

Multi-function probe (MFP): Pitot, AOA and TAT
Side-slip angle (SSA) probe
Integrated Static probes (ISP)

ISIS fed by standby pitot and static probes

Question 9

ADR and IRS key output data

Answer 9

ADR: Speed/Mach, Alt, VS, Pressures, AOA

IRS: Position, velocities, attitude, heading

Question 10

MMR (Multimode receiver)

Answer 10

Receives data from:
GPS satellites and ground stations a
IRS
ILS
Both FMS

Sends data to both PRIMs/PFDs etc to control deviation for each type of approach (ILS, GLS and FLS) - they also build the pseudo-beams for GLS and FLS

Question 11

Surveillance system

Answer 11

2 identical systems comprising:
Wx radar and PWS
Terrain awareness and warning system (TAWS)
TCAS and Transponder