Air navigation for BS aviation undergraduate programme . This ppt explains basic concepts of air navigation. this is used to teach BS aviation, undergrad

1. NAVIGATION and FLIGHT
PLANNING

2. OUR EARTH
• Poles
• Great Circle
• Equator
• Small Circle
• Meridian
• Prime Meridian
• Longitude
• Latitude

3. Great Circle
• Great Circle is any circle that circumnavigates the Earth
and passes through the center of the Earth. A great circle
always divides the Earth in half, thus the Equator is a great
circle (but no other latitudes) and all lines of longitude are great
circles

4. Great Circle

5. Equator
• Great circle around Earth that is everywhere equidistant from
the geographic poles and lies in a plane perpendicular to
Earth’s axis. This geographic Equator divides Earth into the
Northern and Southern hemispheres and forms the imaginary
reference line on Earth’s surface from which latitude is
reckoned; in other words, it is the line with 0° latitude. Earth’s
circumference at the geographic Equator is about 40,075 km

6. Equator

7. Equator

8. Equator

9. Meridian
• a meridian is the line connecting points of equal longitude,
which is the angle (in degrees) east or west of a given prime
meridian. In other words, it is a line of longitude.

10. Meridian

11. Meridian

12. Longitude
• Longitude is a geographic coordinate that specifies the east–west position
of a point on the surface of the Earth, or another celestial body. It is
an angular measurement, usually expressed in degrees and denoted by
the Greek letter lambda (λ). Meridians are semicircular lines running
from pole to pole that connect points with the same longitude. The prime
meridian defines 0° longitude; by convention the International Reference
Meridian for the Earth passes near the Royal Observatory in Greenwich,
England on the island of Great Britain. Positive longitudes are east of the
prime meridian, and negative ones are west.

13. Longitude

14. POSITION ON EARTH
• TYPES OF LATITUDE
• the Arctic Circle,
• the Antarctic Circle,
• the Equator,
• the Tropic of Cancer,
• the Tropic of Capricorn.

15. POSITION ON EARTH
•

16. POSITION ON EARTH
• TYPES OF LATITUDE
• geocentric
• latitude or angle at the center of the Earth between the plane
of the celestial equator and a line (radius) to a given point on
the Earth's surface
• astronomical
• angle between the plane of the earth's equator and the plumb
line (direction of gravity) at a given point on the earth's surface
• geographic.
• the measurement of distance north or south of the Equator. It
is measured with 180 imaginary lines that form circles around Earth
east-west, parallel to the Equator

17. POSITION ON EARTH
• TYPES OF LONGITUDE
• The two main longitudes are the Prime Meridian
and the 180° meridian. The two longitudes divide
the earth into two equal halves, the Eastern
Hemisphere and the Western Hemisphere.
Therefore, the longitude of a place is followed by the
letter E for the east and W for the west.

18. POSITION ON EARTH
• TYPES OF LONGITUDE
• Lines of longitude are lines which join all places
having the same angular distance east or west of the
Prime Meridian. All lines of longitude are semicircles
of equal length. Lines of longitude are also called
Meridians because all places along a lines of
longitude experience mid-day at the same time

19. GEOGRAPHICAL LATITUDE

20. Types of Maps
Types of Maps
There are various types of maps, but in a broader spectrum they can be classified as the scale maps and
thematic maps.
Scale Maps. Maps according to scale are the following:
(i)Cadestal Maps. These are the maps drawn on a very large-scale up to 25 or more inches to a mile.
(ii) Topographical Maps. These are also drawn on a large scale. The scale ranges from 1
inch to a mile or four or more inches to a mile. The survey maps fall under this category.
(iii) Chorographical Maps. These are the small-scale maps of the various parts of the world
showing the typical features by conventional signs. The atlas maps fall under this category.
(iv) World Maps. These are also the small-scale maps showing the whole world.

21. Types of Maps
Thematic Maps. These maps are classified according to some important feature, which they
show.
• An outline map shows only the boundaries of continents and countries.
•
• A political map shows the political boundaries, states, districts, towns, roads and railways etc.
• A relief or physical or Orographical map represents the nature of the land surface.
• A bathymetric map shows the depth of the ocean.
• A bathy orographical map is a combined map showing the depths of the ocean and heights of
the land surfaces.
• An ethnographical map locates the distribution of the races of mankind.
• A vegetation map is the one showing the distribution of natural vegetation.

22. Types of Maps
• A biological map shows the distribution of flora and fauna.
• A weather map is a map showing the distribution of temperature, pressure and
rain fall for a short period only.
• A climatic map shows the distribution of temperature, pressure, rainfall or wind,
for a particular season.
• A geological map shows the distribution of rocks.
• A commercial or economic map is for showing the areas of productions,
distribution of exports and imports, density of population, railways and other
routes.
• A distribution map shows the distribution of some commodity or stock or crops.

23. DISTANCE

24. DISTANCE
• In spherical calculations it is frequently convenient to express spherical
distances (i.e. great circle distances) in terms of angular measurements
rather than in linear units. This is possible because of simple relationship
between radius, arc and angle at the centre of a circle. Thus the length of
the arc of a great circle on the Earth might be expressed as 10 38’; this
would convey little unless there were some ready means of converting
angular units to linear units. This difficulty of converting from angular to
linear units has been overcome by the definition of the standard unit of linear
measurement on the Earth, the nautical mile.

25. Nautical mile:
Assuming the Earth to be a true sphere, a nautical mile is defined as length of
the arc of a great circle which subtends an angle of one minute at the centre of
the Earth. Thus the number of nautical miles in the arc of any great circle equals
number of minutes subtended by that arc at the centre of the Earth. In the figure
below, if AB, the arc of a great circle, subtends an angle at the Earth’s centre of
40 20’, AB is said to be 40 20’ in length. 40 20’ is equivalent to 2,420 minutes
of arc which is equal to a length of 2,420 nautical mile.
2420NM

26. Nautical mile
•A more accurate definition of the nautical
mile is that it is length of the arc on the
earth’s surface that subtends an angle of
one minute at its own centre of curvature.
The length of a standard nautical mile is
6080 ft on earth’s surface.

27. Statute Mile
The other mile unit in common use is
the statute mile. It is the unit of linear
measurement whose length is 5280 ft. it
is purely arbitrary unit of measurement
and, unlike nautical mile, is not readily
converted into angular measurement
terms

28. Kilometre
This unit is the length of 1/10,000th part of
the average distance between the equator
and the either pole; it is equivalent to 3280 ft

29. DIRECTION

30. Direction
• In order to fly in a given direction it is necessary to be
able to refer to a datum line or fixed direction whose
orientation is known or can be determined. The most
convenient datum is the meridian through the current
position, since it is North-South line. By convention
direction is measured clockwise from North, to the
nearest degree, i.e. from 000 to 360. It is always
expressed as three-figure group; thus East which is
90 from North, is written 090, and West 270

31. Direction
•True Direction: Direction measured
with reference to True North, the
direction of the North geographic pole, is
said to be the True direction.

32. Direction
• Magnetic Direction: The Earth acts as though it is a huge magnet
whose field is strong enough to influence the alignment of a freely
suspended magnetic needle anywhere in the world. The poles of this
hypothetical magnet are known as the North and South magnetic poles
and, like those of any magnet, they can be considered to be connected by
the magnetic lines of force. Although the magnetic and geographic poles
are by no means coincident (the respective North poles are separated by
approximately by 900 NM), the lines of force throughout the equatorial
and temperate regions are roughly parallel to Earth’s meridians. A freely
suspended magnetic needle will take up the direction indicated by the
Earth’s lines of force and thus assume a general North-South direction;
the actual direction in which it points, assuming no other influences are
acting upon it, is said to be Magnetic North.

33. Direction
• Compass Direction: When a freely suspended magnetic
needle is influenced only by the Earth’s magnetic field, the
direction it assumes is known as Magnetic North. If such a
needle is placed in an aircraft, it is subject to a number of
additional magnetic fields created by various electrical circuits
and magnetized pieces of metal within the aircraft; consequently
its North-seeking end deviates from the direction of magnetic
North and indicates a direction known as compass North

34. Direction
• Variation: The angular difference between the direction of True North and
Magnetic North at any given point, and therefore between all the True
directions and Magnetic directions at that point, is called Variation. Variation
is measured in degrees and is named East (+) or West (-) according to
whether the Magnetic North lies East or West of the True North. The
algebraic sign given to Variation indicates how it is to be applied to magnetic
direction to convert it to True direction. At any point, therefore, the True
direction can be determined by measuring Magnetic direction and then
applying the local Variation. A useful mnemonic is:
•
• “Variation east, Magnetic least, Variation West, Magnetic best”
•

35. Direction
•Agonic Lines
There may be places on the surface of the Earth
at which the variation is zero i.e. there is no angular
difference between True north and the Magnetic
North. Lines joining points of zero variation are
known as agonic lines.

36. Direction
•Track The direction of the path of an aircraft over
the ground is called its track. Track is measured in degrees
and is expressed (like heading) as a three figure group e.
045. It may be measured relative to true north, magnetic
north or grid north and is annotated (T), (M) or (G)
accordingly.

37. Direction
•Heading-It is the direction in which the
longitudinal axis or nose of the aircraft is
pointing. It is expressed in degrees from
north. The variation and deviation must be
known in order to inter-change true,
magnetic and compass headings.

38. Bearing
It is the direction of a given point, measured
clockwise from a specific reference datum, to a
second point. It can be magnetic, true and Grid
etc. depending on the reference datum (North).

39. DIRECTION
• WIND
• Heading
• Track

40. Types of Flight Rules
• VFR
• IFR

41. Types of Navigation
• Pilotage
• Dead Reckoning
• Instrument/Radio Navigation
• Satellite navigation(GNSS)
• INS-Inertial Navigation

42. DIRECTION
•Track Required (TR).
The line joining two points which it is
required to fly is known as track required

43. DIRECTION
•Track Made Good
In flying from one point to another the path which
the aircraft actually follows over the ground is called
its track made good. When the track made good
coincides with the track required, the aircraft is said
to on the track; when track made well and track
required are not the same the aircraft is said to be
off track. The angular difference between TR and
TMG is known as Track Error (TE).

44. Drift
The angle between the heading and the track of an aircraft is
called drift. Drift is due to the effect of wind and is the lateral
movement imparted to an aircraft by the wind. An aircraft flying in
conditions of no wind, or directly upwind or downwind,
experiences no drift. In such cases, track and heading coincide.
Under all other conditions track and heading differ by a certain
amount, referred to as the drift. Drift is expressed in degrees
to port (P) or starboard (S) of the aircraft’s heading; an aircraft
experiencing port drift is said tot drift to port, and its track lies to
port of his heading.

45. Deviation
The angular difference between the direction of Magnetic North
and that of Compass North, and therefore all Magnetic directions
and their corresponding Compass directions, is called Deviation
•Deviation of a compass will change:
•As its position in the aircraft is changed.
•After a lapse of long period.
•As the aircraft flies great distances over Earth

46. Scale of the Map
The scale of a map is the ratio between a given length on the map and the
actual distance this length represents on the earth’s surface. To bring
down a map to a size that is usable, everything must be reduced in size at
a uniform rate. The scale of the map indicates the amount to which those
objects have been reduced.
• The proportion, which the distance between any two points on the maps
bears to the horizontal distance between the same two points on ground,”
is defined as the scale of a map.
• Scale = Map Length
Earth Distance

47. Scale of the Map
• In words. 1 inch to 1 mile or 1” = 1 mile. This means that one inch on
the map represents one mile on the ground.
• (b) Representative fraction (RF). This is the scale expressed in the form of a
fraction, which is written in following ways: -
• 1/25,000 or 1: 25,000
• This means that one unit of length on the map represents 25,000 of the same
units on the ground.
• (c) Scale line. This method is used to show the scale by a line drawn on
almost every map showing graphically the map distance that represents
certain ground distance.

48. LEGEND OF THE MAP
•For the easy understanding of the map
and to make the map a user-friendly
tool, the legend is marked on the map
.It depicts the conventional signs used
in the map, how the relief features are
represented and the colours used in
colour-tinting.

49. Numerical

50. TN MN
DEVIATION
CN
05
10
125

51. • TH= 150
• Variation= 12 E
• MH & CH

52. • TH= 150
• Variation= 12 E
• Deviation=6 W
• MH & CH

53. • 1 NM = 1.852 km
• 1 NM= 1.15 Statute miles
• 1 Statute mile = 1.6 km

54. AIR SPEED
• IAS- Indicated airspeed- Reading on an airspeed indicator
• CAS-Calibrated Air speed- Calibrated airspeed (CAS) is indicated
airspeed corrected for instrument errors, position error (due to incorrect
pressure at the static port) and installation errors.
• EAS- Equivalent Air Speed-Equivalent airspeed (EAS) is defined as the
airspeed at sea level in the international standard Atmosphere at which
the (incompressible) dynamic pressure is the same as the dynamic
pressure at the true airspeed(TAS) and altitude at which the aircraft is
flying
• TAS- True Air Speed- The true airspeed (TAS; also KTAS, for knots true
airspeed) of an aircraft is the speed of the aircraft relative to the airmass
in which it is flying. The true airspeed and heading of an aircraft constitute
its velocity relative to the atmosphere

55. AIR SPEED

57. Calculating True Air speed
• Add 2% of IAS for every 1000 feet increase in altitude
• IAS=200 Kts
• What will be TAS at 10,000 feet

58. QUIZ
1. What is a Rhumb Line? (2 Marks)
2. Aircraft is flying at 10000 feet with an indicated airspeed of 150
KTAS. What will be its TAS ? (3 Marks)
3. City A is located at N 20 E 30 and city B is located at N 20 E60. Time
in city A is 9 AM. What will be the time in City B? (3 Marks)
4. What are the methods to express scale of the maps. Enumerate .
(2 Marks)

60. SEMI CIRCULAR RULE
• The default worldwide semi-circular rule is the East/West
orientation of the flight level parity:
- Your aircraft has track between 0° and 179°, your flight
level or altitude must be odd.
- Your aircraft has track between 180° and 359°, your flight
level or altitude must be even

61. SEMI CIRCULAR RULE
•By following the semi-circular rule, a VFR aircraft
will limit possible conflicts between other
aircraft coming in opposite direction by
providing 1000ft separation between opposite
west/east tracks

62. SEMI CIRCULAR RULE

63. Safety Altitude
• The safety margin is a combination of
•
• Air Flow Effect: In the area of high obstacles and high ground, windy
conditions may cause a local reduction in pressure, resulting in the
altimeter over reading.
• Temperature / Altimeter Errors; The inherent errors of the pressure
altimeter combined with errors caused by atmospheric variation from
ICAO standard cause the instrument to give incorrect indications in the
vertical displacement.

64. Safety Altitude
• From a map select the elevation of the highest obstacle
in the Zone of Error, for instance 1,100 feet.
• Add 10% for airflow effect: 1,100 + 110 = 1,210 feet.
• Add 1,500 feet for temperature error and altimeter
setting error, giving a total of 2,710 feet, which is the
safety altitude.

65. Radio Nav System
•Types of Radio Nav Aids
•NDB(NON DIRECTIONAL BEACON)
•VOR(VHF OMNI DIRECTIONAL RANGE)
•ILS(INSTRUMENT LANDING SYSTEM)
•DME(DISTANCE MEASURING EQUIPMENT)
•GNSS(GLOBAL NAVIGATIONAL SATELITE SYSTEM)

66. NDB
• A Non-Directional Beacon (NDB) is a ground-based radio transmitter that
emits low-frequency signals. NDBs are used to help guide aircraft and
vessels during their approach.

67. NDB
• signals that are received by the Automatic Direction Finder (ADF). The
ADF is a standard instrument on board aircraft. The signal contains a
coded element that identifies the station, usually 1-3 letters
in Morse Code. .

70. VOR

75. ILS COMPONENTS
•Localizer
•Glidepath
•Markers

76. DME
•provides very accurate slant range, a circular position line and
in conjunction with another DME, or a co-sited VOR, two
position line fixes.
• integrates the change of slant range into groundspeed and
elapsed times when the aircraft is fitted with an appropriate
computer.
• permits more accurate flying of holding patterns and DME
arcs.

77. DME
•provides range and height checks when flying non-
precision approach procedures, e.g. Locator only and VOR
let-downs.
• indicates accurate ranges to the runway threshold, and
heights for range, when flying an ILS/DME procedure.
• facilitates radar identification when the pilot reports his
VOR/DME position.

82. RADARs
•Primary Radar
•Secondary Surveillance radar

83. Primary Radar
•A surveillance radar system
which uses reflected radio
signals.
•Source: ICAO Doc 4444 PANS-
ATM

86. Primary Radar
• PSR principle of operation
• The PSR output data uses polar coordinate
system - it provides range and bearing of the
targets found in respect of the antenna
position. Note that the range is the slant
distance from the antenna and not the
horizontal distance.
• The range is determined by the time difference
of the emitted and received pulse (the speed of
propagation is the speed of light) and the
bearing is obtained from the antenna azimuth.

88. Primary Radar
•The antenna radiation
pattern is a narrow beam
when seen from above and,
with some approximation,
can be considered as a
trapezium if seen from
the side.

89. Primary Radar
• Advantages
• PSR is the only surveillance sensor used in
civil aviation that does not require any on-
board equipment to locate aircraft. Unlike
SSR, ADS-B and MLAT it can discover an aircraft
experiencing Transponder Failure or an
intruder.

90. Primary Radar
• Limitations
• Cone of silence. Due to the radiation pattern, there is a
part of the airspace above the antenna that cannot be
surveyed. This effect is mitigated by placing an array of
radars in such a way that each radar's cone of silence is
covered by another radar.
• Targets with the same slant range (at different levels)
are hard to distinguish (the blips received will overlap).
This is mitigated by combining the PSR with an SSR that
can recognize the different aircraft by their transponder
codes.
• Difficult correlation. Due to the data received (position
only) it is not possible to use automatic correlation.
Manual correlation (after proper aircraft identification)

91. Primary Radar
• Limitations
• The radar relies on reflected signals but is not aware if
they are received from aircraft or from other objects (e.g.
terrain, buildings, clouds). Such reflections are called
clutter. This can somewhat be mitigated by processing the
data using an MTD (moving target detector). This feature
uses the doppler shift of the received signal to determine
whether it came from a stationary or a moving target.
• No level data available. Civil PSRs do not have the ability
to obtain target level. This may be mitigated either by
receiving pilot reports or by combining the PSR with other
types of sensors. Note that some military radars have this
feature (either by using a second antenna or an antenna

92. Primary Radar
• Limitations
• Unambiguous range limit. When receiving the signal it is
not possible to determine the corresponding emitted pulse.
Therefore, a false target can be detected (usually close to
the radar) if the reflected signal reaches the antenna
after a second pulse is transmitted. This effect is
mitigated by adjusting the transmitted energy and the
antenna rotation speed.
• Minimum range limit. The PSR operates on one frequency
which means that it cannot emit and receive signal at the
same time. If the target is too close to the radar antenna,
the reflected signal may be received before the end of the
transmission. If that happens, the target will not be
detected. Note that shortening the pulse will also reduce
the amount of emitted energy thus limiting the maximum

93. Secondary Radar
•A surveillance radar system which uses
transmitters/receivers (interrogators)
and transponders.
•Source: ICAO Doc 4444 PANS-ATM
•

95. Secondary Radar

96. Secondary Radar
• Principle of operation
• The radar antenna rotates (usually at 5-12 rpm) and transmits a
pulse which is received by the onboard equipment (transponder).
The transponder sends back a reply containing at least a code
(if operating in Mode A) but more often this is combined with
level (mode C) or other information, e.g. aircraft
identification, selected level, etc. (Mode S). The information
received depends on the interrogation mode (A, C or S) and the
transponder capability. For example, interrogation in Mode A
will receive a reply in mode A even though the transponder may
have Mode C or Mode S capability and an interrogation in Mode C
will not trigger a response from a Mode A transponder.
Typically, two Mode A interrogations are followed by a Mode C
interrogation. The reason for using Mode A more frequently is
that the identity of the aircraft (the SSR code) is of greater

98. Secondary Radar
• Advantages
• Requires much less power to achieve the desired range, in
comparison to PSR. This is because the transmitted signal only
needs to reach the aircraft, while the PSR needs to emit a
signal strong enough to reach the aircraft and travel back to
the antenna.
• The information provided is not limited to range and bearing
from the antenna but also includes additional data based on the
transponder mode of operation (A, C or S).
• Targets are easier to distinguish due to the different SSR
codes.
• SSR is immune to clutter as it uses different frequencies for
interrogation (1030 MHz) and replies (1090 MHz). Consequently,
even if an echo on 1030 MHz is received, it is not processed by
the system. Therefore, terrain, buildings and weather phenomena

99. Secondary Radar
• Limitations and issues
• The SSR relies on the onboard equipment to discover
aircraft. In case of transponder failure the SSR will
receive no reply and will therefore not discover the
target. This is mitigated by combining the SSR with a PSR.
If proper signal processing is used, it is possible to
continue to track an aircraft (and preserve Correlation)
even if the transponder has failed completely provided
that reliable primary data is received. Note that in this
case level information will be less reliable and more
frequent pilot reports will be necessary.
• Sometimes two replies are received at the same time (if
the slant range and the bearings of the aircraft the
same). This phenomenon is called "garbling" and may result
either in the "detection" of a false (non-existing)

100. Secondary Radar
• Limitations and issues
• Another phenomenon that may produce false indication is FRUIT
(False Replies Unsynchronised In Time or False Replies
Unsynchronised to Interrogator Transmissions). This happens
when the radar receives a reply from a transponder that has
been interrogated by another radar. Since all SSRs operate on
the same frequencies, it is not possible to detect that the
reply is related to another radar's transmission. Moreover, as
the time of the interrogation is not known, the range
calculation will most likely be wrong. As a result, a false
target may appear on the situational display. Additionally, if
another (valid) transponder reply is received at the same time,
garbling could occur. Garbling and FRUIT are aggravated by the
need of "classic" SSRs to use several interrogations for proper
azimuth determination and can be mitigated by:
• Using an MSSR (monopulse SSR). This is an advanced radar that uses a
different beam pattern that provides more accurate azimuth
determination. As a result, fewer interrogations are required to
determine the azimuth.

101. Secondary Radar
• Limitations and issues
• SSRs are vulnerable to antenna shadowing (i.e. the
onboard antenna is shadowed by the aircraft fuselage,
e.g. due to the bank angle). This is mitigated by
placing more than one antenna (usually two - one on
top of the aircraft and one at the bottom).

104. TCAS

105. TCAS

107. Final project
• ILS
• VOR
• TCAS
• ADF
• DME slant range and ground distance
• Primary RADAR(Antenna)
• Secondary RADAR scope
• Runway with PAPI
• Runway with various distance markers(inner, middle, outer)

108. • Calculate TAS of an aircraft, flying at an IAS of 300 knots, at an altitude of
20,000 feet
• Point A is 20 degrees and 10 minutes apart from Point B on a navigation
map. Calculate the ground distance in nautical miles.
• Your heading is 220 degrees and highest obstacle enroute is10,000 feet .
Calculate safety altitude for VFR and IFR flights
• City A is located at N 10 E 20 and City B is located at N 20 E 120. Time at
City A is 6 AM. What time will it be in City B?

110. • Calculate the distance from angular difference
• Calculate various headings
• Calculate bearing to fly (even ,odd)
• Calculate TAS from IAS
• Calculate safety altitude
• Converting units of distance measurement
• Calculate the time difference