ATA 34 – NAVIGATION

  • Air Data/Inertial Reference System (ADIRS)
  • Landing and taxing aids
  • Independent position determining
  • Dependent position determining

ADIRS

  • 3 Air Data/Inertial Reference Units (ADIRU) > ADIRU 1, ADIRU 2, ADIRU 3.
    • Air data function through its Air Data Reference (ADR) portion.
    • Attitude, heading and position function through its Inertial Reference (IR) portion.
  • Standby systems
    • ISIS
      • ISIS indicator replaces 3 conventional standby instruments –
      • Standby altimeter
      • Standby airspeed indicator
      • Standby horizon indicator
    • Standby Compass – for standby heading ……… (independent instrument)

Landing and Taxiing Aids

  • Paravisual Indicator (PVI) (optional system)
  • Head Up Display (HUD) (optional system)
  • Instrument Landing System (ILS) (optional system)  >>> MMR
    • The primary function of the Multi-Mode Receiver (MMR) is to receive and process Instrument Landing System (ILS) and Global Positioning System (GPS) signals.
    • The MMR also receives the approach data from the Global Navigation Satellite System (GNSS) Landing System (GLS) function.
    • The MMR is a navigation sensor with two internal receivers – ILS receiver & GPS receiver. >> (ILS receiver – Localizer and Glide/slope).
    • 2 MMRs – MMR1 and MMR2, linked to:
      • Localizer and Glide/slope antenna
      • GPS antenna

Independent Position Determining

  • Weather Radar (WXR) system
  • Radio Altimeter (RA)
  • TAWS – Generic Term
    • Ground Proximity Warning System (GPWS)
    • EGPWS
  • TACS – Generic Term
    • Traffic Alert and Collision Avoidance System (TCAS)
    • Traffic and Terrain Collision Avoidance System (T2CAS)
    • Traffic and Terrain Collision Avoidance System (T3CAS)

Dependent Position Determining

  • Distance Measuring Equipment (DME)
  • Air Traffic Control (ATC)
  • Automatic Direction Finder (ADF)
  • VHF Omni-Range (VOR)
  • Global Positioning System (GPS) (optional system)

Training Note

  • Why pitot/static port both side (cross connection) – to minimize error.
    • Static – position error
  • Total 8 ADM – all are interchangeable
  • Pitot – 3
  • Static – 6
  • Pitot probe – total pressure
  • ISIS – direct connection to port not through ADM
    • Source – pitot – stby pitot probe / static – stby static probe
  • Laser gyro – total 3 – inside ADIRU (IR part).
    • 2 beam in each gyro – beam travel time
    • Error signal in terms of frequency
    • Frequency is inversely proportional to time.
  • IR inside
    • 1 ring laser gyro for each axis
    • 1 accelerometer for each axis
  • There is a separate 3 axis accelerometer for FDR. (do not confuse with accelerometer inside IR)
  • Water drain in stby static port – because direct source for ISIS.
  • Mode selector unit (MSU) of ADIRS (- ADIRS MODE)
    • NAV
    • ATT – only heading
  • ISIS
    • ATT/SPEED/ALT – Same place as in PFD.
  • BUGS + LS – press for at least 2 sec. >> maintenance mode.
  • LS – press to avail localizer and glidescope.
  • BUGS – for BUGS setting. Press bugs only.
  • Red flag – if system is inop. (eg. ATT , HDG in red)
  • Mean sea level – for altitude calculation
  • QNH – sea level atmospheric pressure
  • In NEO only – ISIS test can be done through MCDU.
  • GPS – 360 degree – divided into 6 >> each 60 degree
  • When GPS is active – no VOR/DME/ADF is required.
  • VOR/DME – single unit
  • All DME are installed with VOR at ground >> VOR + DME – all VOR station
  • If tune VOR – automatically tune DME, frequency are paired and installed at ground together.
  • VOR/DME on ND
    • VOR 2 – VOR sys 2
    • VIDP – Airport
    • 34 NM – given by DME
  • Minimum 4 satellite – GPS position (normally 6 are available)
  • MMR – 90 VU
  • ILS 1 – PFD 1 & ND 2
  • ILS 2 – PFD 2 & ND 1
  • GPS is primary navigation now.
  • GPS Monitor Page on MCDU
    • MERIT – 100 >> GPS accuracy is up to 100 meter
    • mode/set
    • NAV/6 – 6 satellite
    • TRK – heading
  • TAT 1 – only ADIRU 3. — stby
  • ADIRU 1 — TAT 1.
  • Normal
    • MMR 1 – ADIRU 1, 3 – GPS 1
    • MMR 2 – ADIRU 2 – GPS 2
  • If ADIRU 2 fails –
    • ADIRU 2 >> ADIRU 3
    • Switch for GPS 2 input
      • ATT heading selector knob switching (?)
  • FMGC
    • IR 1 & IR 2 – pure data – FMGC 1 & 2
    • Pure GPS data – FMGC 1 & 2
  • MMR > GPS data > ADIRU > FMGC
  • Weather radar transmitter with predictive windshear system function in option.
  • In old a/c – Map mode – map selection >>>> in WXR system
    • Ground picture (antenna will tilt down)
    • Now – EGPWS is doing the same function.
  • PWS – 5 NM (class range) – takeoff/landing
  • Precipitation rate –
    • > 50 mm/hr – turbulence
    • 12 – 50 mm/hr
  • Windshear indication on ND – Red & Black + warning on PFD
  • CAL knob – minimum position, use for testing.
  • WXR antenna
    • Holes for passing magnetic field
    • Waveguide – hollow tube – less distance required for waveguide, that’s why separate self in 90 VU.
    • Optical cable required less distance.
  • Multiscan – top/down & left/right
  • WXR related indication  – ND only
  • PWS related indication – ND + meaning (details) > on PFD
  • Aft side of WXR antenna – BOARD – for protection from return waves.
  • WXR stabilization signal from – ADIRU 1
  • PWS
    • below 2300 feet RA.
    • Aural warning through – FWC (windshear ahead)
  • If warning for the same time – PWS / TCAS & EGPWS >> PWS warning is inhibited.
  • RA auto ON – no switch
  • RTTR
  • RA indication on PFD.
  • Cooling fan – 2 for 2 RA transmitter
  • TA / RA advisory
    • 4 volume
    • Indication on ND
  • GPWS – database updated at every defined time.
  • GPWS system has no antenna. It takes data from sources and computes.
  • ELS >> ADS-B (is enhanced version) >>> ADS-B – IN/OUT
  • Many Airlines have ADS-B — OUT only.

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