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THE

PILOT

radio
navigation
ATPL
STUDENT
pilot
resume

all info you need to pass atpl exams

Radio theory
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Phase: Fraction of one wavelength expressed in degrees from 000 - 360
Cycle: A complete series of values of a periodical process
Frequency: Number of oscillations/cycles per second of an electromagnetic wave
Phase difference: ANGULAR difference between two cycles of equal wavelength
Wavelength (λ) = Speed of light (m/s) ÷ frequency (Hz)
SSB: Used in HF & VOLMET, AM
Modulation: Addition of a low frequency signal onto high frequency carrier wave
Phase modulation: Used by GPS, Helical antennas as GPS have circular polarization
Pulse modulation: Radar
NON A1A modulation/keying: Interrupting carrier wave to break it into dots & dashes does not change
frequency or amplitude

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MSI: Modulation, signal, information
Keying: Interrupting the carrier wave to break it into dots & dashes

Antennae
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Electrical field E same direction as aerial
Magnetic field H perpendicular to aerial
Antennae length = half wavelength (λ)
POLARIZATION: Orientation of the plane of oscillation of the electrical component E
AC induced parallel to wire, but remote from it
First wire radiates energy to space, second wire induces AC
Flat (Slotted) plate eliminates/generates less side lobes than parabolic
Helical antennae used by GPS due to circular polarization
Radar uses one antenna for both transmitting and receiving
Directional antennas: Loop(ADF), parabolic, slotted planar, helical
Dipole antennas: Are the simplest
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- Lower frequency, greater attenuation
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(SKYWAVES) (Used by HF)
Interference: Superimposition of two radio waves of same frequency
Night effect/Fading: Occurs at night, Interference of ground wave with sky wave, Ionospheric
reflection
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23 x (√Transmitter + √Receiver)
QUJ: True TO station (To Juliet)
QTE: True FROM station
QDM: Magnetic TO station (To your Mom)
QDR: Magnetic FROM station

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Provides HOMING, measures RELATIVE TO/AT STATION
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Military uses UHF
Multi-path error results in bearing error
Uses loop & sense antenna
Night effect: Fluctuating indications

NDB/ADF
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NDB frequency: 190 - 1750 kHz, HECTOMETRIC/KILOMETRIC wavelength
MH + RB = MB (My hairy red balls make babies) [MB to station aka QDM]
Power new ÷ Power old = (Range new ÷ range old)2
ADF/NDB error: +/-5 ° generally
To double range, power x 4
Maintaining RB = maintaining CONSTANT TRACK
RB angle between where I’m heading(AC nose) to where ADF needle is pointing
True bearing is always given FROM VDF station (QTE)
NDB/ADF variations at AIRCRAFT
VOR variations at the STATION
Difference between HOMING & TRACKING
Range of NDB determined by power & surface (land/water) not affected by aircraft height
Land range = 2 √Power in watts
Sea range = 3 √Power in watts
BFO circuit: Makes A1A signal identifiable by Morse
LOCATERS: Used for ILS, different from NDB in operations and power
EN-ROUTE: Long range, LF A1A
What does the arrow at the tip of the RMI indicate? QDM
ERRORS:
Mountain effect: Reflection (For some reason)
Night effect/Fluctuations/Fading: Interference of REQUIRED ground wave with sky wave, sky
wave distortion of null, max at dusk & dawn, sky wave reflected from ionosphere (Only for
NDB/ADFs)
Static interference: Thunderstorms (Most significant)
Coastal refraction: Higher ALT = Lesser error
Quadrantal: Refraction of aircraft fuselage
Absence of failure warning
Loop null error: When plane of loop is at right angles to direction of transmitter

VOR
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Phase difference = radial from VOR
RADIAL: Magnetic bearing of aircraft FROM station
NDB/ADF variations at AIRCRAFT
VOR variations at the STATION
CVOR signal: Rotates at 30 times/second giving characteristics of 30Hz AM
DVOR: Uses frequency modulation (FM), more accurate
Using VOR outside published range, may cause interference from other transmitters
Quoted accuracy applied at all times
VOR switches off when there is measured error greater than 1°
VOR frequency: 108 – 117
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g
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25, 108
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1 in 60: Angle a = (Distance off track x 60) ÷ distance along track
Same radial, different distance: Reference & variable both unequal

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Different radial, same distance: Reference equal & variable unequal
TO/FROM indicator: Tells whether track equal to selected bearing will bring you to or away from VOR
Questions on CDI/OBS disregard magnetic heading, questions on HSI take into account magnetic
heading
ERRORS:
• Scalloping (Only for VOR)
• Uneven propagation over irregular ground surfaces
• Compass stuck & RMI working: RB unavailable, radial available
• RMI stuck & ADF still working: RB still available

DME
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ILS
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UHF, 960 MHz – 1215 MHz, approx
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But the accuracy of the groundspeed
function/reading/indication increase with increase in range because the difference between ground
range and the slant range gets bigger, groundspeed less accurate near DME
Co-located VOR/DME: In 40s DME IDENT sounds once at 1350 Hz (Higher pitch)
For ENR: 600m/2000ft apart, for APP: <100ft
DME/P : +/- 0
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25NM + 1
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1 – 111
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5°, one dot glideslope = 0
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45° x glide path (LOWER EDGE); 1
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Localiser transmitter position 300m behind end of runway
Glideslope transmitter position 300m behind threshold
False beams found above correct glide path
1 in 60: [Glide slope x distance x 6080] ÷ 60
ROD = 5 x GS [For 3° glide slope]

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Marker
Modulation
Distance
Outer
400Hz
4NM
Middle
1300Hz
0
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04 – 0
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Wavelength must be longer than precipitation/water
droplets to be able to penetrate
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AWR
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Frequency = 9375MHz, SHF CENTRIMETRIC wavelength to detect LARGE water droplets
Two modes:
Pencil beam: Primary mode, 3-5°, Range = >50-60NM, more power, narrow
Fan shape/cosecant beam: Covers a large area, independent of distance
Used in MAP mode, 80°, 50 – 60NM
Stabilized on pitch & roll
Hazardous to personnel on the ground
ISO-ECHO: Detect areas of possible turbulence in clouds
Auto tilt: Used when changing altitude
Height ring: Determines whether AWR is working
Map mode: Ground/terrain indicated
Turbulence indicated by fingers, hooks, scallops
Increasing range = increasing radar sensitivity using the GAIN knob
During climb tilt decreased and vice versa
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OFF during take-off, ON during landings
Single very bright line indicates scanning of cathode ray tube is faulty
Height=[tilt-beam width/2] x range x 100ft

SSR
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Ground transmitter : 1030 MHz, Aircraft transponder: 1090 MHz, separated by 60Mhz
Principle of transponder/interrogator, echo return not used
Two pulses received plus additional control pulses between them
P2 pulse is used to distinguish between side lobes
P4 pulse: A pulse after pulse train, two types
Short: Mode S blocked, mode A/C all call
Long: Mode A/C/S all call
Mode S:
Data-link &IDENT with 16 million combinations
Mode S Broadcast for all Mode S transponders
Mode S Selective = Interrogate only one transponder
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Interval between pulse 1 & 3 = 8µs
Mode C: Sends pressure altitude info in increments of 100ft
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ALT – Mode A/C/S transmitted
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Garbling: Replies of two or more aircraft in range of less than 1
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Fruiting: Aeroplane at range responding to other interrogations from other ATC stations
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Aircraft can compute an estimate of its
position error
RNP 5/ Basic RNAV: Accuracy +/- 5 NM 95% of flight time
AR: Authorization required
2D: Horizontal
3D: Horizontal & vertical
4D: Horizontal, vertical & time
5 dot HSI:
- En-route: 1 dot = 1NM
- Approach: 1 dot = 0
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5°
- Glide slope: 1 dot = 0
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5NM

2D RNAV
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Uses navigation computer which solves basic sin/cosine trigonometry, calculates & uses auto
computed values, cross track error, distance to go & desired course for tracking on CDI/HSI
Phantom station: A waypoint defined by radial & distance of a VOR/DME
VOR/DME does not have to be in range when entered, but must be when in use
Errors: When in limit range at low altitudes (When near DME slant range error)

4D RNAV
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Cross track distance is distance between actual position & great circle track between active waypoints,
displayed by ND,CDU & HSI
Position of waypoints entered via Lat/long, alphanumeric ICAO identifier or radial & distance
Selection/entering of the flight plan can only done manually by pilot using the CDU
Dead reckoning mode inputs TAS, heading & last computed W/V, occurs when only one VOR
information is used or when radial or distance information is not received
Wind vector calculated from heading of INS/IRS/compass system & TAS from ADC
ETO: Estimated time over significant point
Rho: DME, Theta: VOR
Question tips:

- Differentiate between LATERAL & VERTICAL functions
- Differentiate between INPUTS & OUTPUTS of 4D RNAV
FMS
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Total system error: position error in a (NPA) non-precision approach = +/- 0
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Position fix uses more than one
Pseudo range: Includes clock error, clock bias satellite time correction of receiver clock (By using 4
satellites)
PRN: Code for ident of one satellite & measurement of time for signal to reach receiver, PSEUDO =
fake, calculated range includes receiver clock error
Receiver most suitable: Multichannel
Selective availability (S/A): Degrades GPS by manipulating/dithering satellite signals
RAIM: Integrity monitoring of satellites within the receiver to ensure accurate navigation, can detect
& identify which satellite is faulty
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5°, denies any receiver use of SAT below mask angle
GPS most accurate with 3 SAT at low elevation in 120° azimuth & one directly overhead
“All in view”: Tracking more than 4 required satellites, all within receiver’s mask angle & can easily
replace any lost signal
“Search the sky”: Starts if there is no stored satellite data available
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5 minutes
GPS has 4 clocks: 2 rubidium & 2 hydrogen clocks
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However, clocks of the satellites are synchronized with clocks on the ground (control segment)
Aerial installed on top of fuselage above COG
Galileo:
- Frequency: 1164-1215MHz, 1260-1300MHz, 1559-1591MHz
- Has a new method of spectrum spread signals
- 3 sections: Timing, signal generation & transmit
Number of satellites:
- 3: 2D fix
- 4: 3D fix & correction of receiver clock error
- 5: 3D fix with RAIM capability with exclusion of faulty SAT
- 6: 3D fix with RAIM capability with no exclusion of faulty SAT
Navigation message includes 5 data:
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Ephemeris:
- Position & orbit of that satellite
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Ionospheric model/delays:
- To calculate the delay of GPS signals
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Control:
- Ensures transmitted data is controlled & updated from time to time
- Sends new ephemeris & sat clock error data to GPS

- Consists of master control stations, monitor stations & ground antennas
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User:
- Auto selects appropriate satellite,
- Track signals & measure time taken by signals from satellite to reach the receiver
- Determines elevation & azimuth data of satellite by calculating using almanac data in nav message
• Errors:
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Ephemeris: Solar winds, gravity of sun/moon/planets
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GPS not within accuracy limits: Flight continued by conventional navigation
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Path delay is proportional to the inverse of the carrier frequency squared
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RNAV & RNP 1
RNAV 2
RNP 2
RNAV 5
RNAV 10 & RNP 4 (Extended by updating)
A - RNP

Phase

Approach
All except oceanic, remote & approaches
Arrivals & departures (SIDs & STARs)
En-route, arrival & departure
En-route, oceanic & remote
En-route, arrival
Oceanic & remote
Includes everything

Errors:
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Flight technical error (FTE): Accuracy of the crew flying the path
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Total system error (TSE): Sum of all errors
Path terminators: Specific type of termination of previous path
- IF: Initial fix
- TF: Track fix
- CF: Course to fix
- DF: Direct to fix
- FA: Fix to altitude
- CA: Course to altitude
- RF: Radius to fix - curved terminal or approach section defined by a fix, radius and arc length
- FRT: Fixed radius turn for en-route/approach sections

Instrument
MLS (TRSB)
AWR
Aerodrome surface movement radar

Wavelength
Centimetric
Centimetric
Centimetric

Frequency
5
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09GHz
9375MHz

SHF
SHF
SHF

Low altitude radio altimeter (FM)
High altitude radio altimeter (FM)
Aerodrome surveillance radar

Centimetric (2 aerials)
Decimetric (2 aerials)
Decimetric

SHF
UHF
UHF

Terminal area radar
Long range radar
GPS/SBAS (Phase modulated)

Decimetric
Decimetric (1 aerial)
Decimetric

UHF
UHF
UHF

DME (Pulse modulated)
ILS glideslope (AM)
ILS localiser (AM)
GBAS
Marker Beacon

Decimetric
Decimetric
Metric
Metric
Metric

UHF
UHF
VHF(Odd)
VHF
VHF

960-1125MHz
108-112MHz
108-112MHz
108-112MHz
75MHz

200NM
10NM:8° (Captured at 3 – 10NM)
25NM:10° 17NM:35°
30km
OM:4NM/MM:0
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04NM

VHF radio/ VDF
CVOR (AM)/ DVOR (FM)
HF communications/VOLMET (AM)
Locator

Metric
Metric
Hectometric
Hectometric/Kilometric

VHF
VHF(Even)
HF
LF/MF

118-136MHz
108-118MHz

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