Aircraft Autopilot Systems Overview

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Questions and Answers

What mode is always associated with CLB mode during flight?

SPEED

THR CLB

NAV mode

ALT mode (correct)

What is the purpose of the SRS (Speed Reference System) during an engine failure?

To maintain vertical speed V2 10kt up to ACC ALT (correct)

To maintain a constant speed regardless of altitude

To engage auto-pilot functions for descending only

To switch automatically to manual control

At what altitude does NAV mode activate when a flight plan is inserted?

200 ft

50 ft

30 ft (correct)

100 ft

What happens when both ILS ground transmitters fail?

LOC FD remains active, but deviations flash Signup and view all the answers

What triggers the AUTOLAND feature at low altitudes?

Below 200 ft if both autopilots trip off Signup and view all the answers

What must occur for an approach with NPA to disconnect the autopilot?

When 400 ft MDH is reached or MDA is set to 50 ft Signup and view all the answers

What is required when the accuracy is low during an NPA?

To fly using USHDG or TRACK FPA Signup and view all the answers

What does the auto yaw compensation do in case of engine failure?

It adjusts the damper at to and GA Signup and view all the answers

At what Nz level does the FADEC turn off continuous ignition when in AUTO mode?

Nz 501 Signup and view all the answers

What should be done if dry cranking is aborted during the starting procedure?

Wait 15 minutes before attempting again Signup and view all the answers

What happens when the MASTER switch is ON in manual start mode?

Both igniters are activated Signup and view all the answers

Which of the following conditions requires selecting IGN START before takeoff?

Heavy rain Signup and view all the answers

What is the maximum time allowed to recharge the starter following four consecutive cycles?

15 minutes Signup and view all the answers

How is the LP fuel value affected during the starting process?

It is increased by 1151 in flight Signup and view all the answers

When is the starter not to be engaged according to the starting procedure?

When Nz is above 20 Signup and view all the answers

What indicates a start fault during the engine start procedure?

MASTER CAUTION light activation Signup and view all the answers

What happens when the selected speed drops below VLs regarding ATHR?

ATHR will not allow speed to decrease below VLs. Signup and view all the answers

In what scenario does A FLOOR become unavailable?

If ATHR is disconnected for more than 15 seconds. Signup and view all the answers

Under which conditions is the LOW ENERGY warning inhibited?

When operating under GPWS ALT law. Signup and view all the answers

What is the purpose of FMGL in flight operations?

To command pitch up for a positive ROC. Signup and view all the answers

When is the WINDSHEAR warning message activated?

Between 100 ft and 2000 ft RA. Signup and view all the answers

How does the system react if the Angle of Attack (AoA) becomes too high?

Flybywire protection disengages. Signup and view all the answers

What is required to turn off ATHR when exiting floor mode?

Turning off ATHR manually. Signup and view all the answers

What occurs when the aircraft's speed drops significantly during approach?

ATHR commands a full thrust automatically. Signup and view all the answers

What occurs if the air cycle machine (ACM) fails due to compressor turbine seizure?

The affected pack reverts to heat exchanger cooling mode with reduced flow. Signup and view all the answers

Which component is responsible for modulating temperature in the system?

Bypass Valve Signup and view all the answers

What happens when pack flow is not sufficient in the system?

Zone Controller sends a demand to increase engine idle and raise pressure. Signup and view all the answers

Which of the following statements is true regarding the Anti-Ice Valve?

It is pneumatically operated and electrically controlled. Signup and view all the answers

What is the main purpose of the heat condense extract mechanism in the system?

To remove moisture that may hinder performance. Signup and view all the answers

What does the yellow speed trend indicate during flight?

The speed the aircraft will reach in 10 seconds Signup and view all the answers

What happens if three ADRs fail?

A backup speed scale is displayed based on AOA configuration Signup and view all the answers

Which of the following is true when the aircraft is in direct law?

The aircraft falls from normal mode to direct law with 2 RA failures Signup and view all the answers

What must be selected to eliminate RMP control from the FRAC?

Both NAV must be selected on RMPs Signup and view all the answers

How is the GPS initialized in the aircraft?

By completing the INITA on the MCDU Signup and view all the answers

Which GPWS mode alerts the pilot to terrain closure?

MODE2 Signup and view all the answers

What is the function of the TCAS system?

It interrogates transponder replies from nearby aircraft Signup and view all the answers

What is indicated by the amber RA at 100ft above DH if there is no DH set?

The aircraft is too low for safe navigation Signup and view all the answers

Study Notes

Final App Mode

THRCLIMBmode is engaged when CLB is active, adjusting pitch to achieve the target speed
CLB is always linked to ALTmode, hence the switch from THR CLB to SPEED
SRS (Speed Reference System) is a vertical mode to maintain V2 + 10kts or V2 in case of engine failure up to ACC ALT
NAV activates at 30ft when a flight plan is inserted

Approaches

APPR can be armed with 20C and GS when ILS and RA are not faulty and both receivers have identical FFQ and course settings
In case of ILS ground transmitter failure, APFD remains in LOC FD
LOC and GS deviations are lost, and FD bars flash
In case of dual receiver failure, LOC GS HDG US AP turn off, and their scales are removed
CANCEL APP or land when runway is in sight
Below 400ft, if LOC and GS are engaged, it switches to LAND, only disengageable by a GA
FLARE activates below 30ft
AUTOLAND is triggered below 200ft if both APs trip off, excessive deviations occur (LOC 15ft, GS 100ft), or LOC and GS signals are lost
In case of NPA, AP disconnects at 400ft, MDH, or MDA 50ft AGL if no MDH is set
If accuracy is low, fly NPA using USHDG or TRACK FPA (Flight Path Angle)
In case of NPA, push APPR, arm FINAL, and APPNAU if USHDGTRKFPA, APP NAV if NAV was engaged
Clear waypoints not belonging to the APP
FINAL APP is active on descent profile
Disengage FINAL APP if LOC TRK or FPA is selected
Display raw data for VOR ADF on ND for crosschecking

Protections

In case of engine failure with AP, auto yaw compensation occurs in all modes, achieved by FAC, damper, and GA
Automatic rudder trim is active in all modes
AP FD SRS pitch mode automatically adjusts the reference target guidance speed
Low speed protection features include: ATHR SPEED mode, LOW ENERGY warning, α FLOOR protection, and WINDSHEAR protection
If selected speed is below VLS, ATHR will not allow speed to decrease below VLS
If speed drops below VLS, an aural warning "SPEED SPEED SPEED" will sound, followed by turbulence shear and ATHR OFF
An energy level is calculated by FAC considering horizontal deceleration and flightpath angle
LOW ENERGY warning is triggered between 100ft and 2000ft RA and in CONF 2, 3 FULL, just before floor detection
LOW ENERGY warning is inhibited by GPWS ALT law, DIRECT law, or both RA failures
If the drop continues, AoA increases, and α FLOOR engages, inhibiting the LOW ENERGY warning
FAC processes α FLOOR and ATHR commands FULL THRUST
If ATHR was OFF, it turns ON automatically
α Floor is available from lift-off to 100ft RA, lost in case of failures or ATHR disconnect for over 15 seconds
α Floor is also lost in engine out situations when slats are extended
α Floor is lost in alternate or direct law
When exiting the floor, TOGA LK mode requires turning OFF ATHR to control the aircraft, allowing re-engagement
WINDSHEAR is indicated by a red WINDSHEAR message on both PFDs and an aural alert for 15 seconds
WINDSHEAR is available from 3 seconds after lift-off to 1300ft on TO and from 1300ft to 50ft on LDG with at least CONF 1
FMGL provides pitch up commands in SRS mode for positive ROC even if speed drops
In APP GSminifunction, target speed is adjusted for wind correction for safe ground speed
If AoA gets too high, Flybywire protection disengages
AP and Flybywire protections assist the pilot in reacting to windshear situations

Reversion Node

Allows comprehensive autoflight behavior when the pilot modifies FCU
Ensures a flight envelope ON when Nz 16, OFF when Nz 50
In case of reversion node failure, FADEC uses two igniters
Manual start igniters are ON when MASTER switch is ON and OFF when Nz 50

Eng Mode Norm

Provides continuous ignition ON with ENG flame out or EIU failure, selectable with ENG MODE selector IGN START
Ignition AUTO turns off by FADEC at 501 Nz
To achieve continuous ignition, select BACK NORM then IGN START
LP fuel value opens at start value and opens at 1151 in flight
Start faults include fault messages to ECAM, MASTER CAUTION, FAULT light on ENG panel, and ENG lights on
Start faults are controlled by FADEC
AUTO start is aborted due to E.ggIcA, 4EHI, and anticipated marginal start pressure
Use MANUAL START
With the selector set to CRANK, MAN START ON engages the starter for dry cranking
Do not re-engage the starter when Nz 720
Dry cranking procedure stops when MAN START OFF
Dry cranking takes place when MAN START is aborted
EGT limits are 5 minutes for 10 minutes ENG failure
TYGA I 9.5
FART I
BLEED PRESS is 21 psi when Nz 10
Starter limitations include 4 consecutive cycles lasting 12 minutes with 20 seconds between cycles for starter lab cooling
After 4 consecutive cycles, allow 15 minutes for cooling
Don’t engage the starter when Nz 20
MAX REVERSE is 70kts
Before take-off, select IGN start when heavy rain, runway is contaminated, or severe turbulence is present

Fuel System

A320 fuel system cools the IDG exchanger
Total fuel storage is 19004kg
Fuel transfer values are 5573, 6476, and 5573, controlled by FLSWs
Normal fuel transfer is 69 to 691

Speeds

Pressing RCL for 3 seconds clarifies items with EMERCANCEL pb
Yellow speed trend indicates the speed the aircraft will reach in 10 seconds
Green dot indicates the best lift-to-drag ratio
Maneuvering speed in clean configuration, also with one engine out
S speed is slat retract speed on TO, maneuvering speed in CONF 1 on APPR
F speed is flap retract speed on TO, maneuvering speed in CONF 2-3 on APPR
If 3 ADRs fail, a backup speed scale based on AoA and CONF will be displayed
RA Amber appears 100ft above DH if no DH is set, 400ft if DH is set

GPS is initialized by completing INITA on MCDU
ADIRS can be recovered by selecting ATT
Two ILS receivers, VOR DME, DME PFDI, NDI, NDZ PFD, VOR n a, ILSA, ILSZ
NAV on RMPs controls radio tuning
Selecting both NAVs eliminates control by FRAC
If both FMAC fail, RMP1 controls VORZ 9k and RMP2 controls ADFZ
ILS is active on both RMPs
TRANSPONDER operates in-flight only
2x RA failure causes the aircraft to transition from NORMAL to DIRECT law with a landing down scenario
2x RA failure limits APPR to CAT1 ILS only and APPR pb is not usable

PWS & Weather Radar

PWS AUTO is active at 1500ft RA, even if weather radar is OFF
Weather radar operates in all modes except PLAN
GPWS modes include MODE1 (ROD), MODE2 (TERRAIN CLOSURE RATE RA 30ft 2450ft), MODE3 (ALT LOSS TO or GA), MODE4 (TERRAIN CLEARANCE IN NON LANDING CONE), and MODE5 (TOO FAR BELOW GLIDE SLOPE)
EGPWS features terrain awareness display, terrain clearance floor, and use of database
GPWC is controlled by FLAP MODE, inhibited for FLAP 3 landings
TCAS has 2 antennas, 1 channel computer, 2 ATCTransponders
TCAS interrogates transponders, receiving replies

Heat Exchanger & Pack

Primary heat exchanger
Main heat exchanger
Heat condense extract any moisture
Compressor and cooling fan drive the condenser
Bypass value modulates temperature
Anti-ice valve is pneumatically operated
Zone controller sends demand to both EIUS for increased ENG IDLE pressure if pack flow is insufficient
If the air cycle machine (ACM) fails due to compressor turbine seizure, the affected pack reverts to heat exchanger cooling mode with reduced flow

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Description

Explore the intricacies of aircraft autopilot systems including THRCLIMB mode, SRS, and approach procedures. This quiz covers key concepts in managing speed and altitude during flight, particularly under various operational scenarios. Test your knowledge on ILS and autoland procedures.