Auto flight

Question 1

flight director (FD)

Answer 1

displays pitch and roll commands for the pilot to follow in order to achieve a specific flight trajectory
pilot chooses what they want the FD to achieve via the mode control panel (MCP)

Question 2

FD components

Answer 2

MCP- shared with AP
FDC- flight director computer - older
FCC- flight control computer- newer, shared with AP. one for captain and FO and extra as backup
display- ADI or EADI

Question 3

FD display

Answer 3

x-hairs or v-bar
displacement of bar shows directions & magnitude of control deflection required
does NOT show deviation from target flight path- shows you how to reach and maintain target flight path

Question 4

why have an FD?

Answer 4

improves accuracy of flying
improves safety
reduces workload

Question 5

FCC/FDC inputs

Answer 5

FMC 
MCP
rad alt
ADC
IRS
Nav radios

Question 6

FCC/FDC outputs

Answer 6

EADI- (PFD)

FMA- flight mode annunciator

Question 7

FD operation

Answer 7

allowed 
both FD's + AP's ON
both FD's + AP's OFF
FD's ON + AP'S OFF 
FD'S OFF + AP's ON

Question 8

FD & AP modes

Answer 8

FD & AP mostly use same modes
except: 
FD has take off mode, AP does not 
AP has landing mode, FD does not 
both FD's can be on at the same time, not normally possible for the AP

FMA’s tell you what modes are active

Question 9

FD & off path

Answer 9

when off intended flight path FCC calculates optimum instantaneous path to regain the desired trajectory

FD is not a copy of ILS indication
FD gives no info about ILS deviation

Question 10

the 3 axes

Answer 10

longitudinal axis (roll)- primary axis
lateral axis (pitch) - secondary axis
normal axis (yaw) - tertiary axis

Question 11

single axis AP

Answer 11

provides stabilisation in roll

wing leveller

Question 12

2 axis AP

Answer 12

provides stability about the primary & secondary axes

can capture and maintain heading & altitude

Question 13

3 axis AP

Answer 13

stability about all axes
capable of:
co-ordinated turns
capture & maintain- headings, alt, vertical speed, IAS, Mach
capture and track: VOR radial, ILS, Auto land, follow FMS LNAV & VNAV

Question 14

Stability vs Guidance

Answer 14

stability includes:
wing level holding 
pitch attitude holding
yaw damping 
these are not selectable modes they are active behind the scenes

everything else is guidance

Question 15

Inner loop AP

Answer 15

up to x3 depending on AP axes
has an IRS
error detector- sends error signal to FCC
FCC- converts input error signal to output control command to servo based on control law
makes corrections

stabilises and controls

servomechanism

Question 16

Inner loop feedback

Answer 16

control feedback- from servo actuator to FCC, check its actually moving
performance feedback- servo actuator to error detector

Question 17

servo mechanism

Answer 17

small power input converted to a large power output in a strictly proportionate manner

Question 18

Outer loop AP

Answer 18

inner loop still exists
outer- fakes an error signal which inner can correct in order to achieve a particular goal
outer loop provides guidance

Question 19

AP components

Answer 19

sensors
comparators 
computers
amplifiers 
servo-actuators

Question 20

parallel actuators

Answer 20

can move control surface through 100% of range

moves cockpit control column

Question 21

series actuators

Answer 21

can move control surface through 100% of range

cockpit controls remain static

Question 22

Size of control surface deflection depends on

Answer 22

size of the error
rate of deviation
rate of change of rate of deviation

Question 23

CWS- control wheel steering

Answer 23

button on MCP activates it
gives pilot manual control of inner loop datum
pilot use the normal controls to set an attitude
inner loop then holds it
AP still considered to be on

Question 24

Engaging AP

Answer 24

via button on MCP 
before engagement self check checks:
pitch servo
roll servo
yaw damper
trim servo
IRS
FCC
if all good then it engages

Question 25

disengaging AP

Answer 25

MCP button or button on control column or force controls

Question 26

AP automatic synchronisation function

Answer 26

prevents control snatching during engagement active whilst AP is off purpose is to achieve smooth AP engagement if it fails it may prevent AP engagement

Question 27

Auto trim

Answer 27

active when AP on ensures aircraft is in trim when AP is disconnected smooth disengagement

Question 28

Normal Law

Answer 28

always used unless there's a problem roll: converts bank into a roll rate command pitch: converts pitch into a G or load factor command

Question 29

Normal law protections

Answer 29

``` apply throughout the flight envelope pitch limits roll limits G limits high speed stability- gradual increase in attitude to reduce speed, can override high speed protection- abrupt increase in pitch to decrease speed low speed stability - can override low speed protection ```

Question 30

Normal law ground mode

Answer 30

allows full deflection of controls whilst on the ground

Question 31

Alternate law

Answer 31

``` no longer have AP pitch and roll are same as Normal protections reduced, only have: low speed stability high speed stability nothing that the pilot cant override ```

Question 32

direct law

Answer 32

no AP pitch & roll: direct relationship between elevator/ aileron deflection & control column NO protections

Question 33

legal requirement for AP

Answer 33

needed in single pilot operations in IFR or at Night | needs at least heading & altitude hold

Question 34

FMA's

Answer 34

main way of determining AP behaviour active modes- green armed modes- white or cyan - automatically activate when certain conditions are met green box appears around FMA theres been a change and it shows for 10 seconds

Question 35

lateral modes

Answer 35

HDG - hold heading put in MCP VOR - tracks a VOR radial, switches to HDG overhead core of confusion until out other side LOC mode- follows ILS localiser, intercept done on a fixed heading, uses radio deviation law to determine bank requirements LNAV- follows FMS lateral profile. FMS gives the AP bank and heading commands to follow the programmed route Rollout- after an auto land the AP will hold the runway centre line using ILS localiser

Question 36

vertical modes

Answer 36

ALT hold ALT AQ- alt acquire- smooth transition from climb/descent to level flight V/S- target a certain vertical speed LVL CHG- climb or descent change level G/S- holds aircraft on ILS glide slope VNAV- follows FMS vertical profile FLARE- based on rad alt, flares on auto land Flight Path Angle- like V/S mode but holds angle

Question 37

auto throttle mode

Answer 37

N1- holds constant value of N1%, depends on temp and alt IDLE TOGA MCT SPEED- based on either MCP (pilot puts in) or FMC

Question 38

What AT mode does LVL CHG use?

Answer 38

N1 mode- fixed N1 held | speed held constant by pitch

Question 39

What AT mode does V/S use?

Answer 39

pitches to achieve vertical speed auto throttle holds forward speed- MCP/VMC speed mode prioritises required V/S so forward speed may suffer

Question 40

what modes use the AT MCP/FMC speed mode?

Answer 40

``` V/S ALT hold ALT AQ VNAV Flight path angle ```

Question 41

Auto-throttle provides...

Answer 41

provides automatic thrust control from start of take off (it can be used in take off) until landing varies N1 and EPR depending on selected modes and phase of flight

Question 42

Older aircraft auto throttle

Answer 42

use hydromechanical unit MECU- main engine control unit and a PMC- power management computer

Question 43

newer aircraft auto throttle

Answer 43

``` uses FADEC- full authority digital engine control FADEC does: auto eng starts monitor limitations collects data for the instruments controls fuel flow to achieve N1 controls thrust reverser ```

Question 44

Auto throttle capabilities

Answer 44

via various modes it can hold mach no IAS N1

Question 45

exam Q: can auto throttle be used to set a specific N1?

Answer 45

YES | if you disconnect it and set N1 manually via the lever

Question 46

what will the low speed stall prevention do with the thrust ?

Answer 46

may be a system that auto engages TOGA thrust

Question 47

Yaw damper

Answer 47

prevents dutch roll it is NOT the AP rudder channel 2 or 3 for redundancy

Question 48

Yaw damper & detection of dutch roll:

Answer 48

uses: dedicated yaw rate gyro or/ IRS or/ nose mounted lateral accelerometer ADC as an input inputs added to pilot rudder inputs 2 or 3 for redundancy can be in parallel or series with controls

Question 49

can the auto land do the entire landing all the way down to a full stop?

Answer 49

YES pet

Question 50

Auto land requirements:

Answer 50

``` crew qualified aircraft equipped equipment serviceable operator approved RWY has correct equipment ```

Question 51

Minima

Answer 51

minimum visibility requirements at a certain height above the runway to be able to proceed

Question 52

Approach ban

Answer 52

cannot proceed beyond the approach ban unless the required RVR has been reported

Question 53

Alert height

Answer 53

``` 100ft above runway most warning/ cautions are disabled aircraft only tells pilot about thing that prevent an auto land e.g: total AP failure RAD alt failure loss of ILS signal ```

Question 54

auto land FLARE & ROLLOUT

Answer 54

flare- 40ft | rollout keeps centreline once touching down

Question 55

how many AP systems are needed to do an auto land?

Answer 55

2 | ensures there's a cross checking occurring

Question 56

Fail operational

Answer 56

more systems than needed i.e 3 | one can fail and auto land can still take place

Question 57

Fail passive

Answer 57

only 2 systems if signals form them disagree it disconnects both of them failure in fail passive results in a manual landing will be no significant deviation from flight path as aircraft will be in trim