AFDS, landing support systems and autoland

Question 1

AFDS

Answer 1

autopilot flight director system incorporates outputs to a pitch channel, roll channel and sometimes autothrottle takes input from both the FMS or manual inputs from the pilots used for precision landing at low visibility conditions

Question 2

AFDS functions

Answer 2

guidance indication for manual flight control autopilot and autothrottle follow the flight director to automatically control the aircraft altitude, speed and path

Question 3

Flight director function

Answer 3

provide flight path guidance

Question 4

Flight director

Answer 4

faster, smoother response and more precise than the pilot’s perception and interpretation of instrumentation FD provides flight path guidance only to AP the pilot, FD command bars provide visual path/roll cues to follow the manual flight control inputs

Question 5

Autopilot function

Answer 5

manipulate flight controls to maintain smooth, stable, controlled flight and maintain a pre-determined path

Question 6

Autopilot

Answer 6

faster response and more precise than pilot control inputs required path/control derived from Mode Control Panel or FMS autopilots on jet transport aircraft incorporate a Yaw Damper

Question 7

Autothrottle function

Answer 7

manipulate engine power in order to maintain or achieve selected airspeed and/or clim/descent performance

Question 8

Autothrottle

Answer 8

faster response and more precise than pilot autopilot and autothrottle are separate

Question 9

Relationship between FMS, AFDS and flight control system

Answer 9

CDU - pilot interface with the FMS MCP + pilot controls = manual control CDU used to program FMS with lateral routing/vertical guidance/speed schedule

Question 10

ILS - instrument landing system

Answer 10

ground based infrastructure localiser antenna - glideslope antenna high intensity approach and runways lighting to support visual acquisition of the approach/runway environment by the crew aircraft require ILS antennas, precision approach and display equipment combination of radio signal and high intensity lighting arrays to enable a safe landing during instrument meteorological conditions

Question 11

Localiser antenna

Answer 11

transmits two beams either side of the runway’s projected centreline from the upwind/far end threshold VHF ~110MHz 90Hz left and 150Hz right of the runway

Question 12

Glideslope antenna

Answer 12

transmits two beams above(90Hz) and below(150Hz) glideslope from beside the touchdown zone UHF ~330MHz

Question 13

Localiser aerial

Answer 13

aircraft measures the difference in depth of each modulated signal to determine number of degrees left or right of the centreline

Question 14

Glideslope aerial

Answer 14

aircraft measures the difference in depth of modulation to determine the number of degrees above or below the vertical glideslope profile onto the runway

Question 15

Automatic precision approach

Answer 15

Flight director and autopilot provide an automatic precision approach to determine decision height Autopilot is disconnected at decision height and pilot manually lands the aircraft the aircraft intercepts the localiser before the glideslope

Question 16

Categories of instrument landing with autoland

Answer 16

Question 17

Autoland

Answer 17

fully automatic landing conducted by the AFDS including flare, touchdown and sometimes rollout control essential for CAT III landing in poor visibility selector prior to capture of GS by arming all 3 autopilots aircraft performes Built in Test(BIT) of all required equipment and redundant equipment of 1500ft and displays result to crew via Autoland status Annunciator(ASA)

Question 18

Fail operational

Answer 18

3 flight control computers 3 ILS receivers 3 autopilots 3 independent sources full CAT IIIB autoland with no DH can be executed all signals and control outputs are monitored for failures/errors

Question 19

Fail passive status

Answer 19

activated when 1 system fails only CAT IIIA with DH 50ft can be accomplished

Question 20

Autoland functionality - CAT III ILS/GBAS

Answer 20

localiser capture glideslope capture flare runway equipment, steering on runway with rudder and nose wheel steering autobraking go around may be initiated for any reason during approach

Question 21

GNSS instrument approaches

Answer 21

don’t require any ground infrastructure to implement functionality provided by aircraft based device and pre-existing space-based infrastructure cost effective solution

Question 22

LNAV/VNAV

Answer 22

GPS and ABAS(RAIM) for lateral and vertical guidance from barometric altimeter achieves DH of 350ft above the runway

Question 23

LPV

Answer 23

localiser performance with vertical guidance,lateral and vertical guidance provided by GPS and SBAS provide angular guidance DH 200-250ft above the runway

Question 24

Future of GNSS precision approaches with autoland capabilities

Answer 24

highly reliable requires GBAS arbitrary approach path only one system needed multiple GBAS ground reference stations to receive GPS signal and calculate differential corrections and one transmitter station uses current ILS frequency to transmit corrections to the aircraft

Question 25

EVS

Answer 25

enhanced vision system - IR camera on the nose allows approach and runway lights to be seen through cloud, projected on HUD allows crew to continue with a CAT I ILS below 200ft DH down to 100ft before going visual

Question 26

SVS

Answer 26

synthetic vision system terrain and airport database used to overlay synthetic vision of the outside world on the PFD improved situational awareness and safety as a result