Air navigation PILOTS

• Periods 1&2
• INTRODUCTION
• HOW IS AIR NAVIGATION DIFFERENT FROM
• NAVIGATION ON LAND AND WATER?
• FORM OF THE EARTH
• SHAPE, SIZE, AXIS OF ROTATION, GEOGRAPHIC
POLES
• GREAT CIRCLES, SMALL CIRCLE
• GRATICULE, LATITUDE, PARELLELS OF LAT, D
LAT
• MERIDIANS, PRIME MERIDIAN, ANTE MERIDIAN,
• LONGITUDE, D LONG , LAT/LONG POSITION ,
• BEARING AND DIST, PLACE NAME, GRID,
GEOREF SYSTEM

AIR NAVIGATION
• AIR NAVIGATION is the ART and SCIENCE of
taking an Aircraft from Place ‘A’ to Place ‘B’,
Safely and in Shortest Possible TIME, ie Most
Economically
• Most Important aspect of Aviation and involves
not only the in depth knowledge of a wide
variety of subjects but also their
interdependence and co-relation and their
impact on the flight operations

THE THREE W’S OF NAVIGATION
WHERE AM I ?
WHY AM I HERE?
WHAT DO I DO NEXT?

How is Air Navigation different from
navigation on land and water?
PILOTAGE NAVIGATION WITH REFERENCE TO VISIBLEFEATURES

EARTH
• FORM
SHAPE
SIZE
AXIS OF ROTATION
GEOGRAPHIC POLES
GREAT CIRCLES
SMALL CIRCLES
EQUATOR, MERIDIANS & PARELLELS
GRATICULE

SOLAR SYSTEM
The Solar System consists of the Sun ,nine major
planets , including the earth, and approximately 2000
minor planets and asteroids.
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
Pluto
All the Planets orbit around the sun in elliptical orbits in
accordance with Keppler’s Laws of Planetary motion.
Similarly the Earth orbits the Sun in an elliptical orbit at
an average distance of 93 million statute miles from the
Sun.

THE EARTH’S ORBIT
The Earth not only orbits the Sun but also spins
on its own axis, presenting a continuously
changing face to the Sun. This causes day and
night.
The Earth’s axis is inclined at an angle of approx
66.5 degrees to the Orbital Plane. This causes the
seasons on the Earth as well as the changing time
interval between Sunrise and Sunset throughout
the year.

THE POLES
The Poles are defined as the extremities of the
axis about which the Earth spins.
When viewed from above a Pole, if the Earth
appears to rotate in an anti-clockwise direction
then that Pole has been named as the North
Pole.
Similarly, if viewed from above a Pole , the Earth
appears to rotate in a clockwise direction then
that Pole has been named as the South Pole.

SHAPE OF THE EARTH
OBLATE SPHEROID
a solid generated by revolution
of an ellipse
about its
minor
axis
Equatorial Diameter= Polar Diameter + 27 Statute Miles
6865 NM
6888 NM
Compression or Flattening = Eq Dia – Polar Dia
Eq Dia

Topographical SurfaceTopographical surface Mountain
Geoid
Ellipsoid
Ocean

GREAT CIRCLE
• IS A CIRCLE ON THE SURFACE OF A SPHERE
(EARTH) WHOSE CENTER AND RADIUS ARE THE
SAME AS THOSE OF THE SPHERE.
• IT IS THE LARGEST CIRCLE THAT CAN BE DRAWN
ON THE SPHERE .
• IT CUTS THE SPHERE INTO TWO EQUAL HALVES.
• ONLY ONE GREAT CIRCLE CAN BE DRAWN
THROUGH ANY TWO POINTS ON THE SURFACE OF
THE EARTH WHICH ARE NOT DIAMETRICALLY
OPPOSITE TO EACH OTHER.
• THE SHORTER ARC OF THE GREAT CIRCLE
PASSING THROUGH TWO POINTS REPRESENTS
THE SHORTEST DISTANCE BETWEEN THE POINTS

• SMALL CIRCLE: ANY CIRCLE WHICH IS NOT A
GREAT CIRCLE IS CALLED A SMALL CIRCLE.
• EQUATOR: EQUATOR IS A GREAT CIRCLE WHOSE
PLANE IS AT RIGHT ANGLES TO THE AXIS OF
ROTATION OF THE EARTH. IT CUTS THE EARTH
INTO NORTHERN AND SOUTHERN HEMISPHERE.
• PARALELS OF LATITUDE: SMALL CIRCLES WHOSE
PLANE IS PARALEL TO THE PLANE OF THE
EQUATOR .
• MERIDIANS: ARE SEMI GREAT CIRCLES PASSING
THROUGH THE NORTH AND THE SOUTH POLES.A
MERIDIAN PASSING THROUGH A PLACE ALWAYS
DEFINES THE NORTH SOUTH DIRECTION.
• PRIME MERIDIAN: THE MERIDIAN PASSING
THROUGH GREENWICH (LONDON) IS CALLED THE
PRIME MERIDIAN
• ANTI MERIDIAN: THE OTHER HALF OF THE GREAT
CIRCLE COMPLETING THE MERIDIAN IS CALLED
ITS ANTI MERIDIAN
• GRATICULE: NETWORK OF MERIDIANS AND
PARALELS OF LATITUDE IS CALLED GRATICULE.

NP
SP
EQUATOR
GREAT CIRCL
SMALLCIRCLES

BASIC DIRECTIONS ON THE EARTH
NEED FOR A DATUM…………
THE DIRECTION IN WHICH THE EARTH IS SPINNING IS
DEFINED AS EAST. THE DIRECTION OPPOSITE TO EAST IS
NAMED WEST.
FACING EAST, THE POLE ON THE LEFT IS NORTH POLE
AND DIRECTION NORTH IS DEFINED AS THE DIRECTION
TOWARDS THE NORTH POLE
LIKEWISE THE POLE ON THE RIGHT IS THE SOUTH POLE
AND THE DIRECTION SOUTH IS DEFINED AS THE
DIRECTION TOWARDS THE SOUTH POLE. SOUTH IS ALSO
THE DIRECTION OPPOSITE TO NORTH

NORTH
EAST
SOUTH
WEST
CARDINAL DIRECTIONS
OR POINTS
NORTH-EAST
SOUTH-EAST
SOUTH-WEST
NORTH WEST
QUADRANTAL DIRECTIONS
OR POINTS
N
S
EW
NE
SESW
NW

SEXAGESIMAL SYSTEM / TRUE DIRECTION
• SEXAGESIMAL SYSTEM USES THE FACT THAT A CLOCKWISE
ROTATION OF DIRECTION FROM NORTH THROUGH EAST,
SOUTH AND WEST AND BACK TO NORTH IS A CIRCLE OF 360
DEGREES. NORTH IS THUS 000 Degrees, EAST BECOMES 090
Degrees, SOUTH 180 Degrees AND WEST 270 Degrees.
NORTH CAN BE 360 OR 000 Degrees.
• WHEN THE NORTH DATUM IS WITH RESPECT TO THE
GEOGRAPHIC NORTH POLE , THEN THE DIRECTIONS ARE
TERMED AS TRUE DIRECTIONS AND SHOWN AS 000(T) ,
090(T), 135(T) etc
• 090(M) WILL BE THE DIRECTION WITH RESPECT TO THE
MAGNETIC NORTH AND 090(C) WILL BE THE DIRECTION WITH
THE DATUM AS THE COMPASS NORTH

LATITUDE,PARELLELS OF LATITUDE
DIFF OF LAT/DIFF OF LONG
PRIME MERIDIAN/ ANTI MERIDIAN
STANDARD MERIDIAN
POSITIONS EXPRESSED IN TERMS OF
LAT & LONG, BEARINGS AND
DISTANCES

DEFINITIONS
• LATITUDE : LAT OF A POINT IS THE ARC OF THE
MERIDIAN PASSING THROUGH THE POINT
INTERCEPTED BETWEEN THE EQUATOR AND THE
POINT. MEASURED IN DEG, MIN, AND SEC AND IS
TERMED NORTH OR SOUTH DEPENDING ON
WHETHER THE POINT IS NORTH OR SOUTH OF THE
EQUATOR
• LONGITUDE : LONGITUDE OF A PLACE IS THE
SHORTER ARC OF THE EQUATOR INTERCEPTED
BETWEEN THE PRIME MERIDIAN AND THE
MERIDIAN PASSING THROUGH THE PLACE .
MEASURED IN DEG, MIN, AND SEC AND IS TERMED
EAST OR WEST DEPENDING ON WHETHER THE
POINT IS EAST OR WEST OF THE PRIME
MERIDIAN.

• Latitude 40 N
Equator
A Latitude 40 N
E Q
N
S
40°

.
NP
Greenwich
B
0°
Greenwich
Meridian
180° Meridian

DEFINITIONS
• CHANGE OF LAT (Ch Lat/D Lat): BETWEEN
TWO PLACES IS THE SMALLER ARC OF
THE MERIDIAN INTRRCEPTED BETWEEN
THE PARALLELS OF LATITUDE OF THE TWO
PLACES AND IS NAMED NORTH OR SOUTH
DEPENDING ON THE DIRECTION OF THE
CHANGE. MEASURED IN DEG, MIN AND SEC.
• CHANGE OF LONG (Ch Long/D Long):
BETWEEN TWO PLACES IS THE SMALLER
ARC OF THE EQUATOR INTRRCEPTED
BETWEEN THE MERIDIANS OF THE TWO
PLACES AND IS NAMED EAST OR WEST
DEPENDING ON THE DIRECTION OF THE
CHANGE. MEASURED IN DEG, MIN AND SEC

Periods 3&4
DIRECTION
MAGNETIC POLES, RELATIONSHIP
BETWEEN GEOGRAPHIC
AND MAGNETIC POLES
VARIATION, ISOGONALS,
DEVIATION , HEADING (C),(M),(T)
TRACK – MAGNETIC AND TRUE
CONVERSION AND C D M V T
PRACTICE PROBLEMS

Aircraft
HEADING
True
Magnetic
Compass
TN
MN
CN
Variation
(E)
Deviation
(W)
Measurement of Direction

• DIRECTION
MAGNETIC POLES
RELATIONSHIP BETWEEN GEOG
& MAGNETIC POLES
VARIATION, ISOGONALS, AGONIC
LINE
DIP-ISOCLINALS, ACLINIC LINE
TRACK – MAGNETIC AND TRUE
CONVERSION OF COMP DIR TO
MAG AND TRUE AND VICE VERSA

Periods 5&6
UNITS OF MEASURE MENT
NAUTICAL MILE , STATUTE MILE, KILOMETER
RELATIONSHIP NAUTICAL MILE AND LAT
METERS , FEET AND THEIR RELATIONSHIP
TEMPERATURE, UNITS OF MEASUREMENT
POUNDS AND KILOGRAMS
US GALLONS, IMP GALLONS, LITERS AND
THEIR CONVERSION

UNITS OF MEASUREMENT
• NAUTICAL MILE, STATUTE MILE, KM
• METERS AND FEET & THEIR REL’SHIP 1M=3.3 ft
• TEMP; UNITS OF MEASUREMENT
• °C °F °K ( Absolute Temp) X°F=(X-32)x 5/9 °C
Y°C=(Y+273) °K Z °C = (Z x 9/5) + 32° F
• APPRECIATION OF VARIATION OF
LENGTH OF NAUTICAL MILE WITH LAT
• POUNDS, KG 1 Kg = 2.2 lbs
• US GALLONS, IMP GALLONS,LITRES
1 Imp Gal = 1.2 US Gal = 4.55 Ltr
1 US Gal = 3.6 Ltr
• CONVERSION OF THE ABOVE

Periods 7&8
CONVERGENCY, CONVERGENCE OF MERIDIANS
VARIATION OF CONVERGENCY WITH LAT
ITS EFFECT ON G/C TRACKS
RHUMB LINE, DEFINITION, ADV/ DISADV OF R/L TR
VIS-À-VIS G/C TR
CONVERSION ANGLE AND ITS RELATIONSHIP WITH
CONVERGENCY
APPLICATION OF THE SAME

CONVERGENCY
• CONVERGENCE OF MERIDIANS
• VARIATION OF CONVERGENCY WITH
LAT
• EFFECT OF CONV ON GREAT CIRCLE
TRACKS

x
x
x
CONVERGENCY
between Long A and Long B
At Lat C
A
B
Convergency = Ch Long X Sine Mean Lat
CONVERGENCY IS DEFINED AS THE ANGLE OF
INCLINATION BETWEEN TWO SELECTED MERIDIANS
MEASURED AT A GIVEN LATITUDE
C

RHUMB LINE
• DEFINITION : IT IS A REGULARLY CURVED LINE WHICH CUT ALL THE
MERIDIANS AT THE SAME ANGLE
• ADVANTAGES : IT REPRESENTS THE CONSTANT DIRECTION FLIGHT. SO
CONSTANT HEADING CAN BE MAINTAINED. IT OBVIATES THE NEED TO
CONSTANTLY KEEP CHANGING THE HEADING AS IS THE CASE WITH
G/C TRACKS
• DISADVANTAGES : IT DOES NOT REPRESENT THE SHORTEST
DISTANCE. SO IT IS LESS ECONOMICAL IN COMPARISON WITH GREAT
CIRCLE
• CONVERSION ANGLE : THE DIFFERENCE BETWEEN THE G/C TRACK
AND THE RHUMB LINE TRACK BETWEEN ANY TWO PLACES IS CALLED
THE CONVERSION ANGLE.
• RELATIONSHIP BETWEEN CONV ANGLE AND CONVERGENCY:
CONVERSION ANGLE IS EQUAL = ½ CONVERGENCY
THEREFORE CA = ½ CH LONG X SINE MEAN LAT
• ITS APPLICATION; IT IS ESSENTIAL THAT THE
C/A IS APPLIED AT THE POSITION
WHERE THE G/C DIRECTION IS
MEASURED

• Convergency= 70 x Sin30 = 35 Deg
• C/A= 17 ½ Deg
E Q
60N
50W 20E
A
B
NP
SP
R/L
G/C
C/A
C/A

DEPARTURE
• DEPARTURE IS THE E – W DISTANCE
BETWEEN TWO MERIDIANS ALONG A
SPECIFIED LATITUDE, USUALLY IN
NAUTICAL MILES
• IT IS MAXIMUM AT THE EQUATOR AND
ZERO AT THE POLES, WHERE ALL
MERIDIANS CONVERGE
• THEREFORE, DEP VARIES AS Cos LAT
Departure (nm) =Ch Long (Min)xCos
Lat

A B
C D
10 W 20 W
20 N
40 N
POSN A – 40 N 10 W
B - 40 N 20 W
C - 20N 10 W
D - 20 N 20 W
GIVE:THE R/L DIST FROM A – B
THE DEP FROM B TO C
THE DEP FROM CTO B?

Q.1 GIVEN THAT THE VALUE OF EARTH’S COMPRESSION
IS 1/297 AND THAT THE SEMI-MAJOR AXIS OF THE
EARTH, ( MEASURED AT THE EQUATOR) IS 6378.4 KM ,
WHAT IS THE SEMI-MINOR AXIS (MEASURED AT AXIS OF
THE POLES)?
a) 6399.9 km b) 6356.5 km c) 6378.4 km d) 6367.0 km
Q.2 GIVE THE DIRECTION AND CHANGE OF LATITUDE
FROM “A” TO “B” IN EACH OF THE FOLLOWING CASES:
A B
a) 31°27’S 091°47’E 35°57’N
096°31’E
b) 61°47’N 003°46’W 62°13N 001°36’E
c) 43°57’S 108°23’E 43°57N
071°37W
Q.3 YOU ARE AT POSITION “A” AT 54°20’N
002°30’W. GIVEN A ChLat OF 16°20’N AND A

• Q.4 WHAT IS THE POSITION OF THE
RHUMB LINE BETWEEN TWO POINTS
RELATIVE TO THE GREAT CIRCLE
BETWEEN THE SAME TWO POINTS, IF THE
POINTS ARE:
a) IN THE NORTHERN HEMISPHERE
b) IN THE SOUTHERN HEMISPHERE
• Q.5 COMPLETE THE FOLLOWING TABLE
HDG (C) DEVN. HDG(M) VARN HDG(T)
095 100 5W
312 3E 315
138 3W 13 E

• Q.6 GIVE THE SHORTEST DISTANCE IN
NAUTICAL MILES AND IN KILOMETERS BETWEEN
THE FOLLOWING POSITIONS:
A B
a) 52°06’N 002 32’E 53°36’N OO2°32’W
b) 04°41’S 163°36’W O3°21’N 163°36W
c) 62 00’N 093°00’E 62°00’N 087°00’W
d) 00°00’N 176°00’E 00°00’N 173°00W
e) 43°57’N 071°37’W 43°57’S 108°23’W
Q.7 WHAT IS THE SHORTEST DISTANCE
BETWEEN “A” ( 5130N 00000E) AND
“B” (5130S 18000E)

Q.8 WHAT IS THE ANGLE BETWEEN TRUE
G/C TRACK AND THE TRUE R/L TRACK
JOINING THE POINTS “A” (7000S 16000W)
AND “B” (7000S 17900E), AT THE PLACE OF
DEPARTURE ?(Cos70 = 0.34 , Sin70 = 0.94)
Q.9 POSITION “A” IS 58°N 030°W AND
POSITION “B” IS 51°N 020°W. WHAT IS THE
RHUMB LINE BEARING FROM ‘A’ TO ‘B’ , IF
THE GREAT CIRCLE TRACK FROM ‘A’ TO ‘B’
MEASURED AT ‘A’ IS 100°(T)?
a) 110°(T) b) 284°(T) c) 104°(T) d) 090°(T)°

Q.10 THE GREAT CIRCLE BEARING OF
‘E’ FROM ‘F’ IS O90°(T) AND THE
GREAT CIRCLE BEARING OF ‘F’ FROM
‘E’ IS 265°(T). IN WHICH HEMISPHERE
ARE ‘E’ AND ‘F’ LOCATED ?

AERONAUTICAL CHARTS
• SIMPLE THEORY OF PROJECTIONS
• SCALE
• SCALE ERROR
• RELIEF
• SYMBOLS

• PROPERTIES OF AN IDEAL CHART
A. Representation of the Earth’s surface
Areas should be represented in their
true shape on the chart
Equal Areas ON THE Earth Should be
shown as Equal Areas on the Chart
Angles on the Earth should be represented by
the Same (Equal) Angles on the Chart
Scale Should be Constant and Correct
B. Navigation Requirements
R/L Should Be A Straight Line
G/C Should Be A Straight Line
Lat and Long should be easy to plot
Adjacent sheets should fit correctly
Coverage should be Worldwide

SCALE
• DEFINITION
• REDUCED EARTH
• R.F./STATEMENT IN WORDS/
GRADUATED SCALE
• DEVELOPABLE SURFACE
• TYPES OF PROJECTIONS
a) PERSPECTIVE PROJECTIONS
b) MATHEMATICAL PROJECTIONS

SCALE
• Definition: It is the ratio of Chart Length to the
Earth Distance in the same Units
• Scale = Chart Length/ Earth Length (in same
units)
RF 1: 1,000,000
Statement : 0ne inch equals one mile
:Quarter inch Map
Graduated Scale
10 5 0 10 20 30 40 50 60

PROJECTIONS
IDEAL REQUIREMENTS FOR NAVIGATION
• APPEARANCE OF GRATICULE
• SCALE VARIATION
• ORTHOMORPHISM
• CHART CONVERGENCY
• APPEARANCE OF GREAT CIRCLE
• APPEARANCE OF RHUMB LINE
• AVAILABLE COVERAGE
• FITMENT OF ADJACENT SHEETS

SCALE FACTOR
• Scale can never be constant and correct
• Scale Factor is the Factor at which the Scale is
Expanding/ Contracting.
• SF at A = Scale at A / Scale of Reduced Earth
therefore, Scale at A = Scale of RE x SF
• Also, Scale at A = SF at A x Specified scale,
Scale at B = SF at B x Specified scale
Therefore,
Scale at A = SF at A
Scale at B SF at B

SCALE ERROR
• Difference between 1 and Scale Factor
SF = 1.1 , Scale Error = 1.1-1 = +0.1
or, if SF = .99, Scale Error = - 0.01
• Scale Deviation is the scale error
expressed as a percentage.
So

Periods 11&12
MERCATOR / TRANSVERSE MERCATOR
PROJECTIONS
CONSTRUCTION
PROPERTIES
ADVANTAGES/ DISADVANTAGES
USES
LIMITATIONS

MERCATOR PROJECTION - PROPERTIES
• A MATHEMATICAL PROJECTION – BASED ON NORMAL CYLINDRICAL
• ORTHOMORPHIC BY CONSTRUTION
• RHUMB LINES ARE STRAIGHT LINES
• GREAT CIRCLES ARE CURVES CONCAVE TO THE EQUATOR
• SCALE IS CORRECT ONLY AT THE EQUATOR:
BUT SCALE CAN BE MADE CORRECT AT ANY OTHER STATED LAT
SCALE IS NOT CONSTANT – EXPANDS AWAY FROM THE EQUATOR
• AREAS ARE NOT CORRECTLY REPRESENTED: EXAGERATED – LAT
• SHAPES DISTORTED SPECIALLY IN HIGHER LATITUDES
• CONVERGENCY IS CONSTANT AT 0°(Correct only at Equator) -
MERIDIANS ARE ALL PARELLEL ST. LINES
• COVERAGE – POLES CAN NEVER BE PROJECTED
PROJECTION IS USEFUL FOR NAV UPTO ABOUT 70 DEG LAT.
IT WAS ONE OF THE MAIN PROJECTIONS USED FOR PLOTTING
CHARTS. MAIN DISADVANTAGES- DOES NOT FOLLOW SHORTEST
DIST. TR. AND RADIO BEARINGS NEED TO BE CORRECTED
BEFORE PLOTTING ( APPLICATION OF CONVERSION ANGLE)

MERCATOR PROJECTION
• SCALE FACTOR: AT EQUATOR SF = 1
MEANS SCALE IS CORRECT AT THE EQUATOR
SCALE EXPANDS AWAY FROM THE EQUATOR AS
SECANT OF LAT
SO SCALE AT ANY LAT = SCALE AT EQ X SEC LAT
• SCALE CAN ALSO BE MADE
CORRECT AT TWO
PARALLELS
• SCALE CONTRACTS
BETWEEN THEM
EXPANDS OUTSIDE
SCALE CORRECT
AT THESE LAT’S
SCALE REDUCES
TOWARDS EQUATOR

OBLIQUE MERCATOR
E Q
NP
SP
FALSE EQUATOR
THE PROPERTIES ARE
IN RELATION TO THE
FALSE EQUATOR.
PROJECTION OF
THE GRATICULE
IS COMPLICATED.

OBLIQUE MERCATOR
APPEARANCE OF GRATICULE

TRANSVERSE MERCATOR OF THE NORTHERN HEMISPHERE

Periods 13&14
SIMPLE CONIC/ LAMBERT’S
CONFORMAL
CONSTRUCTION
PROPERTIES, CONSTANT OF THE
CONE
PARALLEL OF ORIGIN, STANDARD
PARALLEL
GRATICULE
PROPERTIES – SCALE, G/C , R/L
USES
LIMITATIONS

CONICAL PROJECTIONS
• CYLINDRICAL PROJECTIONS ARE MOST SUITED TO COVER AREAS
CLOSE TO A GREAT CIRCLE, LIKE THE EQUATOR
• AZIMUTHAL PROJECTIONS ON THE OTHER HAND ARE MOST SUITED
TO COVER AREAS AROUND A POINT, LIKE THE POLES
• CONICAL PROJECTIONS ARE THE MOST SUITED FOR THE AREAS IN
BETWEEN THE TWO, NAMELY THE MID LATITUDES
• IF YOU PLACE A CONE WITH THE APEX ABOVE THE POLE AND
PLACE THE LIGHT SOURCE AT THE CENTER OF THE REDUCED
EARTH, THE GRATICULE WILL BE PROJECTED ON TO THE
DEVELOPABLE SURFACE
• THE LAT ITUDE AT WHICH THE CONE IS TANGENTIAL, THE LENGTH
OF THE PARALLEL OF LAT ON THE REDUCED EARTH AND ON THE
PROJECTION WILL BE EQUAL. IN OTHER WORDS , THE SCALE
FACTOR WILL BE ONE : SCALE WILL BE CORRECT. THIS LAT IS
CALLED THE PARELLEL OF ORIGIN.
• NUMERICALLY, THE VALUE OF PARELLEL OF ORIGIN IS EQUAL TO
HALF THE APEX ANGLE.

THE FAMILY OF TRUE (PERSPECTIVE) PROJECTIONS
CONSTANT OF
THE CONE = 1
CONSTANT OF THE
CONE = 0
CONSTANT OF THE
CONE =>0 <1
CYLINDRICAL CONICAL
AZIMUTHAL

CONICAL PROJECTIONS
Semi Apex Angle
= Lat of Parallel
of Origin
ө =
ө
ө
PARALLEL OF
ORIGIN
E Q
NP
SP
NORMAL CONICAL
APEX OF THE CONE IS ON THE AXIS OF
ROTATION OF THE EARTH (EXTENDED)
PARALLEL OF ORIGIN
THE PARELLEL AT WHICH THE CONE IS
TANGENTIAL TO THE REDUCED EARTH
DEPENDS ON THE APEX ANGLE
SCALE WILL BE CORRECT ALONG THIS
STANDARD PARELLEL
ONE WHICH IS PROJECTED AT THE
REDUCED EARTH SCALE. ON A ONE
STANDARD PARELLEL PROJECTION
IT IS ALSO THE PARELLEL OF ORIGIN
CONSTANT OF THE CONE
RATIO OF ANGLE OF THE SEGMENT WHEN
DEVELOPED TO 360° IS CALLED THE

• Basically depends on the apex (semi-
apex) angle.
• Constant of the cone varies from 0 for
cylindrical projections to 1 for azimuthal
projections
• Constant of the cone is mathematically
equal to sine of the parallel of
origin/standard parellel i.e. sine of semi
apex angle for the simple conic .

LAMBERT’S CONFORMAL
• A NON PERSPECTIVE PROJECTION ON TO
A CONE TANGENTIAL AT A LAT CHOSEN AS
THE PARELLEL OF ORIGIN
• IT HAS TWO STANDARD PARELLELS i.e.
SCALE IS MADE TO BE CORRECT ALONG
THESE TWO PARELLELS WHICH ARE
APPROXIMATELY EQUALLY SPACED
ABOUT λ○. SCALE FACTOR AT THESE
PARELLELS IS ONE .

Parellel of Origin
Standard Parellels

• PROPERTIES
 MATHEMATICAL PROJ BASED ON CONIC WITH
TWO STANDARD PARALLELS
 ORTHOMORPHIC
 SCALE : CORRECT ALONG THE TWO STANDARD
PARELLELS ; EXPANDS OUTSIDES AND
CONTRACTS INSIDE THE STD PARELLELS :
EXPANSION OUTSIDE THE STD PARELLELS
IS UNEQUAL i.e. IT IS MORE TOWARDS THE
POLES THAN TOWARDS THE EQUATOR :
SCALE MIN AT THE PARELLEL OF ORIGIN
 CONVERGENCE = n x Ch long
 GREAT CIRCLES ARE CURVES CONCAVE TO
THE PARELLEL OF ORIGIN. DEVIATION BETWEEN G/C
AND A STRAIGHT LINE IS SO SMALL THAT FOR ALL
PRACTICAL PURPOSES A ST LINE IS A GREAT CIRCLE
 RHUMB LINES : WILL APPEAR AS CURVES CONCAVE TO THE
NEARER POLE
 SHAPES AND AREAS : SHAPES ARE DISTORTED : BUT FOR SMALL
AREAS SHAPES MAY BE CONSIDERED REASONABLY CORRECT

SCALE VARIATION ON A LAMBERT’S CONFORMAL

APPEARANCE OF G/C AND R/L ON

Periods 15 &16
AZIMUTHAL PROJECTIONS
Gnomonic ,Stereographic & Equidistant
POLAR GNOMONIC /POLAR
STEREOGRAPHIC PROJECTIONS
CONSTRUCTION
PROPRETIES
USES
LIMITATIONS

NP
PARALLELS OF LAT
PROJECTING LIGHT SOURCE
Appearance of Graticule
NP
MERIDIANS
STRAIGHT LINES RADIATING
OUT FM THE CENTER,
Ie THE POLE

• POLAR GNOMONIC
• Construction:
• This Is An Perspective Projection In Which A Plane Surface
Is Placed Tangential To The Pole And The Light Source Is
Placed At The Center Of The Reduced Earth

POLAR GNOMONIC – PROPERTIES
PERSPECTIVE PROJECTION
POLAR GNOMONIC: GRATICULE APPEARANCE
MERIDIANS – RADIAL STRAIGHT LINEs
PARELLELS OF LAT ARE CONCENTRIC CIRCLES
POINT OF TANGENCY IS ONE OF THE POLES
SCALE INCREASES AWAY FROM THE POLE OFTANGENCY
SCALE FACTOR IS GIVEN BY SECANT (90 – Lat) ALONG THE
LAT AND AS SECANT ² (90 –Lat) ALONG THE MERIDIAN
SO PROJECTION IS NEITHER ORTHOMORPHIC NOR EQUAL
AREA
COVERAGE IS LIMITED TO LESS THAN 90 DEGREES,
i.e. EQUATOR CAN NEVER BE PROJECTED

POLAR STEREOGRAPHIC
THIS IS A PERSPECTIVE PROJECTION
POINT OF TANGENCY : ONE OF THE
POLES
POINT OF
PROJECTION :
DIAMETRICALLY
OPP THE PT OF
TANGENCY
R
R
ө
POINT OF TANGENCY
LIGHT SOURCE
*
*
**
R Cosine ө
ө
2R
**Tan ½ (90- ө)=D/2R
D =2Rx Tan ½ Co Lat
R

POLAR STEREOGRAPHIC PROJECTION
E Q
NP
NP
MERIDIANS
EQUATOR
PARALLELS OF LATITUDE
REDUCED EARTH
SP
PLANE OF
PROJECTION

PRORERTIES : POLAR STEREOGRAPHIC
 IT IS ALSO A PERSPECTIVE PROJECTION
 SCALE EXPANDS ALONG MERIDIANS WITH DIST FM
POINT OF TANGENCY
 SCALE AT ANY POINT IS SAME ALONG PARELLELS
AND MERIDIANS. HENCE IT IS CONFORMAL
 GRATICULE: MERIDIANS ARE STRAIGHT LINES
RADIATING FROM THE POINT OF TANGENCY
PARALLELS OF LAT ARE CONCENTRIC CIRCLES
 RHUMBLINES - CURVES CONCAVE TO THE POLE
 GREAT CIRCLES : ALL MERIDIANS ARE STRAIGHT LINES,
OTHER G/C ARE ARCS OF CIRCLES. DIFFICULT TO PLOT
 SCALE NEARLY CONSTANT : SD < 1% UPT0 7 8.5 Deg
 IT CAN BE EXTENDED BEYOND THE EQUATOR, i.e. MORE
THAN ONE HEMISPHERE CAN BE PROJECTED

Periods17 & 18
TYPES OF CHARTS - Purpose and Uses of different charts
TOPOGRAPHICAL CHARTS
PLOTTING CHARTS
POLAR CHARTS
RADIO FACILITY CHARTS
AERONAUTICAL NAVIGATION, RADIO NAVIGATION,
PLANNING CHARTS
TRRMINAL AREA CHARTS/ INSTRUMENT APPROACH
LETDOWN CHARTS

TYPES OF CHARTS
• TOPOGRAPHICAL CHARTS
• PLOTTING CHARTS
• POLAR CHARTS
• RADIO FACILITY CHARTS
• AERONAUTICAL NAV CHARTS
• RADIO NAV CHARTS
• PLANNING CHARTS
• DANGER AREA/PROHIBITED
AREA/RESTRICTED AREA CHARTS
• TERMINAL AREA / IAL CHARTS

Periods 19 ,20,21 & 22
ELEMENTS OF FLIGHT NAV
SPEEDS – IAS,RAS,CAS,EAS,TAS
DIRECTION- TRUE, MAG, COMP, REL
TRACK- REQD, TMG, TRACK ERROR
HEADING
BEARING/ BACK BEARING
DISTANCE
TEMPERATURE-INDICATED, OAT OR FAT
WIND VEL
DRIFT
GROUND SPEED
AIR POSITION
GROUND POSITION / DEDUCED RECKONING (DR)
POSN
MEASUREMENT OF DIRECTION AND DIST ON A CHART

ELEMENTS OF FLIGHT NAV
• SPEEDS – IAS,RAS,CAS,EAS,TAS
• DIRECTION- TRUE, MAG, COMP, REL
• TRACK- REQD, TMG, TRACK ERROR
• HEADING
• BEARING/ BACK BEARING
• DISTANCE
• TEMPERATURE-INDICATED, OAT OR FAT
• WIND VEL
• DRIFT
• GROUND SPEED
• AIR POSITION
• GROUND POSITION / DEDUCED RECKONING (DR) POSN
• MEASUREMENT OF DIRECTION AND DIST ON A CHART

• DIRECTION
Aircraft
HEADING
True
Magnetic
Compass
TN
MN
CN
Variation
(E)
Deviation
(W)
Measurement of Direction
MEASURED
CLOCKWISE
000° TO 360°
FROM:
TRUE NORTH
(T)
MAGNETIC
NORTH (M)
COMPASS
NORTH (C)

• Track Error
Aircraft
HEADING
True
Magnetic
Compass
TN
MN
CN
Variation
(E)
Deviation
(W)
Track Required
Drift
TMG
©
TRACK ERROR : Angle between Track Required and
Track Made Good Measured Port or
Starboard of Track Required
Track Error 20P
Hdg

Bearings
• The direction or orientation of the fore and aft
(longitudinal) axis of the aircraft, expressed as
an angle measured clockwise from a reference.
• The angle is the bearing from one point to
another.
• Bearings are named by the nature of the
reference:
True North reference – True bearing
Magnetic North reference – Magnetic bearing
Straight ahead – Relative bearings

000
030
330
060
090
300
120
180
270
150
240
210
Rel Brg Ind

BEARINGS: DIRECTION OF PLACE “A”
FROM PLACE “B”
N
N
A
BBEARING OF A FROM B
290°(T)
BEARING OF B FROM A
i.e. RECIPROCAL OF
BRG OF B FROM A
290°(T) ± 180° = 11O°(T)

N000
030
330
060
090
300
120
180
270
150
240
210
Rel Brg Ind
A
A Brs 225(R)
+ HDG(T) 270
= 495-360
= 135(T)

Periods 23 & 24
TRIANGLE OF VELOCITIES
• EFFECT OF WIND ON AN AIRCRAFT IN
FLIGHT
• SOLUTION OF PROBLEMS BY
ESTIMATION
• INTRODUCTION TO COMPUTER /
SLIDE RULE

TRIANGLE OF VELOCITIES
• EFFECT OF WIND ON AN AIRCRAFT IN
FLIGHT
• SOLUTION OF PROBLEMS BY
ESTIMATION

Periods 25 &26,27&28
USE OF COMPUTER/ SLIDE RULE
• PRINCIPLE OF CONSTRUTION
• MULTIPLICATION & DIVISION
• CONVERSIONS
• CALCULATION OF:
• CAS TO TAS , MACH NO. TO TAS,
INDICATED ALT TO TRUE ALT, INDICATED
ALT TO DENSITY ALT , CAS TO MACH NO.&
VICE VERSA , FUEL CALCULATIONS
• SOLUTION OF TRIANGLE OF VELOCITIES

PRINCIPLE OF CONSTRUCTION
CIRCULAR SLIDE RULE BASED ON THE
LOGRARITHMIC SCALE
 IF 10ª = A NUMBER “X”, THEN Log X= a
Conversely Anti Log of a = X
SO IF WE WANT TO MULTIPLY X and Y,
10ª=X and 10ⁿ=Y, X x Y= 10ª x 10ⁿ= 10ª+ⁿ
LIKEWISE, X/Y Can be solved by
 Log X/Y = 10ª - ⁿ

PRINCIPLE OF CONSTRUCTION :
Based on Logarithmic Scale
• Log 10 = 1 ( 10 = 10¹ )
• Log 100 = 2 ( 100 = 10 ² )
• Log 10000 = 4
• Log 10ⁿ = n
_____________________________________________
Log 1 = 0.00000 Log 2 = 0.30103
Log 3 = 0.47712 Log 4 = 0. 60205
Log 5 = 0.69897 Log 6 = 0.77815
Log 7 = 0.84510 Log 8 = 0.90309
Log 9 = 0.95424 Log 10 = 1.00000
Log 90 = 1.95424 Log 8000= 3.90309

Flight Computer
• UNIT INDEX …………………………….. Against 10
• IMP GALLON CONV. ARROW………….. Against 10.7
• KILOMETER -----,,-------,,-----------,,------ Against 12.2
• US GALLON -----,,-------,,-----------,,------.. Against 12.8
• FOOT -----,,-------,,-----------,,------ ……… Against 14.3
• PRESSURE ALTITUDE WINDOW
• LBS CONV. ARROW……………………. Against 35.3
• DENSITY ALT WINDOW
• AIR TEMP WINDOW
• “A” SCALE MILES, MPH,GALLONS, GPH,TAS, TRUE ALT
• “B” SCALE ( TIME IN MIN, CAS, CAL ALT )
• “C” SCALE … TIME IN HOURS AND MINUTES
• TEMP CONV SCALE
• KILOGRAM CONV ARROW …………… Against 16.5 (INNER SCALE)
• SECONDS ARROW ………………………Against 36 (INNER SCALE)
• METERS-----,,-------,,-----------,,------ …… Against 43.5 (INNER SCALE)
• LITERS -----,,-------,,-----------,,------ …… Against 48.5 ( OUTER SCALE)
• SPEED INDEX …………………………… Against 60 (INNER SCALE)
• NAUTICAL MILES CONV. ARROW…… Against 66 ( OUTER SCALE)
• STATUTE MILES CONV ARROW…… Against 76 ( OUTER SCALE)
• FUELPOUNDS CONV ARROW …… Against 77 ( OUTER SCALE)
• OIL/POUNDS CONV ARROW ………… Against 96 ( OUTER SCALE)

FLIGHT COMPUTER
Slide Rule
Time-Speed-Distance
Calculations
Fuel Calculations
Nautical/Statute Conversions
CAS/TAS Conversion
Density Altitude Calculations
Exercise

USE OF COMPUTER/ SLIDE RULE
• PRINCIPLE OF CONSTRUTION
• MULTIPLICATION & DIVISION
• CONVERSIONS
• CALCULATION OF:
• CAS TO TAS , MACH NO. TO TAS,
INDICATED ALT TO TRUE ALT, INDICATED
ALT TO DENSITY ALT , CAS TO MACH NO.&
VICE VERSA , FUEL CALCULATIONS
• SOLUTION OF TRIANGLE OF VELOCITIES

Period 31
METHODS OF DETERMINING
WIND VELOCITY
• TRACK AND GS METHOD- ITS ACC &
LIMITATIONS
• AIR PLOT METHOD – ITS ACC AND
ADVANTAGES
• FMS/GPS/INS WIND VEL

METHODS OF DETERMINING
WIND VELOCITY
• TRACK AND GS METHOD- ITS
ACC & LIMITATIONS
• AIR PLOT METHOD – ITS ACC
AND ADVANTAGES
• FMS/GPS/INS WIND VEL

Periods32&33
NAVIGATION TECHNIQUES
• MAP READING – INTERPRETATION OF
MAP/CHART SYMBOLS
• NECESSITY OF CROSS-CHECKING PIN-POINTS
• MONITORING PROGRESS OF THE AIRCRAFT BY
MAP READING
• MAP READING TECHNIQUES MAP TO
GRD WHEN SURE OF POSN , GRD TO MAP WHEN
UNSURE OF POSN
• DR POSN AND ITS CIRCLE OF ERROR
• METHODS OF DETERMINING TR ERROR AND
ALTERATION OF HDG
• CALCULATION OF GS AND ETA WITH THE AID OF
TIME AND DIST MARKS ON MAP

NAVIGATION TECHNIQUES
• MAP READING – INTERPRETATION OF
MAP/CHART SYMBOLS
• NECESSITY OF CROSS-CHECKING PIN-POINTS
• MONITORING PROGRESS OF THE AIRCRAFT BY
MAP READING
• MAP READING TECHNIQUES MAP TO
GRD WHEN SURE OF POSN , GRD TO MAP WHEN
UNSURE OF POSN
• DR POSN AND ITS CIRCLE OF ERROR
• METHODS OF DETERMINING TR ERROR AND
ALTERATION OF HDG
• CALCULATION OF GS AND ETA WITH THE AID OF
TIME AND DIST MARKS ON MAP

0900
0910
0920 0935
0945
Track Plot of DR Tracks

FIXING POSITION
• POSITION LINE
• USES OF A SINGLE POSITION LINE
TO CHECK TR
TO CHK HDG
TO CHK GS
TO REVISE ETA
TO HOME ON
TO CONSTRUCT AN MPP
• USE OF VISUAL, RADIO AND RADAR
OBSERVATIONS IN FLIGHT

Periods 35&36
PILOT NAVIGATION/MENTAL DR
• ESTIMATION OF TAS BY MENTAL CAL
• MENTAL DR
• ESTIMATION OF TR ERRORS
• 1:60 RULE AND ITS APPLICATION
• CORRECTION TR ERROR
• AH PARELLEL TR / CLOSING ON TR
ESTIMATION OF WIND EFFECT, DIST, DIR,
FLIGHT TIME,TAS AND GROUND SPEED

PILOT NAVIGATION/MENTAL DR
• ESTIMATION OF TAS BY MENTAL CAL
• MENTAL DR
• ESTIMATION OF TR ERRORS
• 1:60 RULE AND ITS APPLICATION
• CORRECTION TR ERROR
• AH PARELLEL TR/ CLOSING ON TR
ESTIMATION OF WIND EFFECT, DIST, DIR,
FLIGHT TIME,TAS AND GROUND SPEED

MENTAL DR
• X-TRACK / ALONG TR COMPONENT
• RAS-TAS ESTIMATION
• SPEED/DIST/TIME CALCULATIONS
• FUEL FLOW/ FUEL AVAILABLE/
ENDURANCE CALCULATIONS
• FEET-METERS/ LBS-KGS

Period 37
PRESSURE PATTRRN
• PRINCIPLE
• MINIMUM TIME TRACKS

PRESSURE PATTRRN
• PRINCIPLE
• MINIMUM TIME TRACKS

Period 38&39
NAVIGATION DURING CLIMB ,
DESCENT AND TURN
CLIMB :-
VARIATION OF RATE OF CLIMB WITH AIRCRAFT WT AND ALTITUDE
CLIMB AT CONSTANT POWER INTER-RELATIONSHIP BETWEEN
RATE OF CLIMB, SPEED AND CLIMB
CLIMB AT CONSTANT AIR SPEED
DETERMINATION OF MEAN WIND VEL FOR CLIMB BY
INTERPOLATIONDETERMINATION OF MEAN HDG AND MEAN
GROUND SPEED FOR THE CLIMB
DESCENT
NAVIGATION DURING DESCENT
INTER-RELATIONSHIP BETWEEN
RoD, AIR SPEED AND ANGLE OF
DESCENT
DETERMINATION OF MEAN HDG
AND MEAN GS FOR THE DESCENT

NAVIGATION DURING CLIMB,
DESCENT AND TURN
CLIMB :-
• VARIATION OF RATE OF CLIMB WITH
AIRCRAFT WT AND ALTITUDE
• CLIMB AT CONSTANT POWER INTER-
RELATIONSHIP BETWEEN RATE OF CLIMB,
SPEED AND CLIMB
• CLIMB AT CONSTANT AIR SPEED
• DETERMINATION OF MEAN WIND VEL FOR
CLIMB BY INTERPOLATION
• DETERMINATION OF MEAN HDG AND MEAN
GROUND SPEED FOR THE CLIMB

DESCENT
• NAVIGATION DURING DESCENT
 INTER-RELATIONSHIP BETWEEN
 RoD, AIR SPEED AND ANGLE OF
DESCENT
 DETERMINATION OF MEAN HDG
AND MEAN GS FOR THE DESCENT

Period 40&41
NAVIGATION DURING TURN & ENROUTE NAVIGATIONAL
PROCEDURES
 INTER-RELATIONSHIP BETWEEN RATE OF TURN, AIR
SPEED ANGLE OF BANK AND RADIUS OF TURN
 TRACKING IN, TRACKING OUT, DETERMINATION OF
RANGE BY CHANGE OF BEARING, UPDATING OF
INS/IRS / FMS BY USE OF GROUND FACILITIES
 INFLIGHT DIVERSION, CRUISING LEVEL
 SPEED SCHEDULE , AERODROME CONSIDERATION
 ETA TO ALTERNATE, FUEL CALCULATIONS

NAVIGATION DURING TURN & ENROUTE NAVIGATIONAL
PROCEDURES
• INTER-RELATIONSHIP BETWEEN RATE OF TURN, AIR SPEED ANGLE
OF BANK AND RADIUS OF TURN
Turn radius R = V² .
g Tan Ф
Rate of turn = TAS/ RADIUS
= g Tan Ф Radians/ Sec
V
• TRACKING IN
• TRACKING OUT
• DETERMINATION OF RANGE BY CHANGE OF BEARING
• UPDATING OF INS/IRS / FMS BY USE OF GROUND FACILITIES
• INFLIGHT DIVERSION
CRUISING LEVEL
SPEED SCHEDULE
AERODROME CONSIDERATION
ETA TO ALTERNATE
FUEL CALCULATIONS

TURNS
• NAVIGATION DURING TURN
• INTER-RELATIONSHIP BETWEEN
RATE OF TURN, AIR SPEED ANGLE
OF BANK AND RADIUS OF TURN
Turn radius R = V² ,
g Tan Ф
Rate of turn = TAS/ RADIUS
= g Tan Ф Radians/ Sec
V
Rate 1 turn ……180Deg /min i.e. 3 deg / sec
(In constant Rate turn, Angle of Bank depends on TAS)
Rate 2 Turn …….360 Deg/Min i.e. 6 Deg/Sec
Rate 3 Turn …….540 Deg/Min i.e. 9 Deg/Sec
R

ENROUTE NAV PROCEDURES
• TRACKING IN
• TRACKING OUT
• DETERMINATION OF RANGE BY
CHANGE OF BEARING
• UPDATING OF INS/IRS / FMS BY USE
OF GROUND FACILITIES

• INFLIGHT DIVERSION
CRUISING LEVEL
SPEED SCHEDULE
AERODROME CONSIDERATION
ETA TO ALTERNATE
FUEL CALCULATIONS

Period 42&43
FLIGHT PLANNING
• PRE-FLIGHT PLANNING
SELECTION OF ROUTE AND ALTERNATE AIRFIELD
PREPARATION OF MAPS / CHARTS
SPEED SCHEDULES
METHODS OF CRUISE CONTROL
EXTRACTION OF DATA FROM FLIGHT PLANNING GRAPHS & TABLES AND ITS
APPLICATION
SELECTION OF OPTIMUM CRUISING LEVEL
NAVIGATION PLAN
USE OF NAVIGATION CHARTS FOR PLANNING FLIGHTS WITHIN AND OUTSIDE
CONTROLLED AIRSPACE
INTERPRETATION AND USE OF THE INFO ON THE CHARTS
SELECTION OF OPTIMUM LEVEL
TERRAIN AND OBSTACLE CLEARANCE
NAVIGATION CHECK POINTS
VISUAL/ RADIO MEASUREMENT OF TRACKS AND DISTANCES
OBTAINING WIND VEL FORECAST FOR EACH LEG
COMPUTATION OF HEADING, GS, AND TIMES ENROUTE FROM TRACKS AND
DISTANCES
TAS AND WIND VELOCITIE
COMPLETION OF PRE-FLIGHT PORTION OF THE NAVIGATION LOG

FLIGHT PLANNING
• PRE-FLIGHT PLANNING
SELECTION OF ROUTE AND
ALTERNATE AIRFIELD
PREPARATION OF MAPS / CHARTS
SPEED SCHEDULES
METHODS OF CRUISE CONTROL
EXTRACTION OF DATA FROM FLIGHT
PLANNING GRAPHS & TABLES AND ITS
APPLICATION
SELECTION OF OPTIMUM CRUISING LEVEL

NAVIGATION PLAN
 USE OF NAVIGATION CHARTS FOR PLANNING FLIGHTS
WITHIN AND OUTSIDE CONTROLLED AIRSPACE
 INTERPRETATION AND USE OF THE INFO ON THE CHARTS
 SELECTION OF OPTIMUM LEVEL
 TERRAIN AND OBSTACLE CLEARANCE
 NAVIGATION CHECK POINTS
 VISUAL/ RADIO MEASUREMENT OF TRACKS AND DISTANCES
 OBTAINING WIND VEL FORECAST FOR EACH LEG
 COMPUTATION OF HEADING, GS, AND TIMES ENROUTE FROM
TRACKS AND DISTANCES
 TAS AND WIND VELOCITIES
 COMPLETION OF PRE-FLIGHT PORTION OF THE FLT PLAN

OBTAINING WIND VELOCITY FORECAST
FOR EACH LEG
COMPUTATION OF HEADINGS/ GS AND
TIMES ENROUTE FROM TR TAS & WV
COMPLETION OF THE PREFLIGHT
PORTION OF THE NAVIGATION
FLIGHT LOG

• FUEL PLANNING
CALCULATION OF FUEL BURN OFF
FOR EACH LEG AND TOTAL BURN
OFF FUEL FOR THE FLIGHT
AIRCRAFT MANUAL FIGURES FOR
FUEL CONSUMPTION DURING CLIMB
ENROUTE AND DURING DESCENT
FUEL FOR HOLDING AND DIVERSION
TO ALTERNATE AIRFIELD
RESERVES , TOTAL FUEL REQD FOR
THE FLIGHT

Period 44&45
FUEL PLANNING
 CALCULATION OF FUEL BURN OFF FOR EACH LEG AND
TOTAL BURN OFF FUEL FOR THE FLIGHT
 AIRCRAFT MANUAL FIGURES FOR FUEL
CONSUMPTION DURING CLIMB, ENROUTE AND DURING
DESCENT
 FUEL FOR HOLDING AND DIVERSION TO ALTERNATE
AIRFIELD
 RESERVES AND TOTAL FUEL REQD FOR THE FLIGHT
 COMPLETION OF PRE FLIGH PORTION OF FUEL LOG
 CALCULATION OF PAY LOAD
 FACTORS AFFECTING PAYLOAD
 AIRCRAFT WEIGHT AT T/O & LDG
 COMPILATION OF LONG DISTANCE
 FLIGHT PLANS (PRACTICAL)

FUEL PLANNING
 CALCULATION OF FUEL BURN OFF FOR EACH
LEG AND TOTAL BURN OFF FUEL FOR THE
FLIGHT
 AIRCRAFT MANUAL FIGURES FOR FUEL
CONSUMPTION DURING CLIMB, ENROUTE
AND DURING DESCENT
 FUEL FOR HOLDING AND DIVERSION TO
ALTERNATE AIRFIELD
 RESERVES AND TOTAL FUEL REQD FOR THE
FLIGHT

FUEL PLANNING (CONT)
 COMPLETION OF PRE FLIGHT
PORTION OF FUEL LOG
 CALCULATION OF PAY LOAD
 FACTORS AFFECTING PAYLOAD
 AIRCRAFT WEIGHT AT T/O & LDG
 COMPILATION OF LONG DISTANCE
PLANS (PRACTICAL)

Period 46
RADIO COMMUNICATION AND
NAVIGATION PLAN
COMMUNICATION FREQUENCIES AND CALL SIGNS
FOR APPROPRIATE CONTROL AGENCIES AND
INFLIGHT SERVICE FACILITIES SUCH AS WEATHER
BROADCASTS, NAVIGATION AIDS (SELECTION
AND IDENTIFICATION)

RADIO COMMUNICATION AND
NAVIGATION PLAN
COMMUNICATION FREQUENCIES AND
CALL SIGNS FOR APPROPRIATE
CONTROL AGENCIES AND INFLIGHT
SERVICE FACILITIES SUCH AS
WEATHER BROADCASTS,
NAVIGATION AIDS (SELECTION and
IDENTIFICATION)

Period 47&48
FLIGHT PLANNING CHARTS
• INTERPRETATION AND USE OF AERODROME CHARTS /SID
STAR CHARTS, TERMINAL AREA CHARTS, ENROUTE LOW
LEVEL/HIGH LEVEL AIRWAYS CHARTS, INSTRUMENT
APPROACH CHARTS.
• TERMINAL CHARTS
• AREA, SID, STAR, AERODROME, INSTRUMENT APPROACH
FORMAT
• TOPOGRAPHICAL INFORMATION
• PROJECTION SCALE
• RADIO NAV AIDS
• REPORTING POINTS/ FIXES
• COMMUNICATIONS
• AIRFIELD INFORMATION
• MINIMUM SECTOR ALTITUDES
• PLAN & PROFILE VIEW OF APP PROCEDURE CHARTS

FLIGHT PLANNING CHARTS
• INTERPRETATION AND USE OF
AERODROME CHARTS /SID STAR
CHARTS, TERMINAL AREA CHARTS,
ENROUTE LOW LEVEL/HIGH LEVEL
AIRWAYS CHARTS, INSTRUMENT
APPROACH CHARTS.

ATC PROCEDURES
• KNOWLEDGE AND COMPLIANCE WITH
ATC PROCEDURES

TERMINAL CHARTS
• Area, SID, STAR, Aerodrome, Instrument
Approach FORMAT
• Topographical Information
• Projection Scale
• Radio Nav Aids
• Reporting Points/ Fixes
• Communications
• Airfield Information
• Minimum Sector Altitudes
• Plan & Profile view of App Procedure Charts

Period 49&50
ATC PROCEDURES/INSTRUMENT APPROACH
PROCEDURES
• KNOWLEDGE AND COMPLIANCE WITH ATC PROCEDURES
• ATIS
• AIRCRAFT APPROACH CATEGORIES
• ENTRY INTO HOLDING PATTREN
• SPEED LIMITATIONS
• MINIMUM SECTOR ALTITUDE (MSA)
• MINIMUM HOLDING ALTITUDE (MHA)
• OBSTACLE CLEARANCE ALTITUDE/ HEIGHT
• CHARTED ALTITUDES PRECISION APP PROCEDURES - (ILS, LOC, VOR, VOR
DME, NDB ,VDF, ASR ,PAR)
• NON-PRECISION APPROACH PROCEDURES
• STRAIGHT IN APPROACH, CIRCLING APPROACH
• APPROACH SEGMENTS
• INITIAL APPROACH FIX
• INTERMEDIATE APPROACH FIX
• FINAL APPROACH FIX
• STEP DOWN FIX
• LANDING MINIMA, DECISION ALTITUDE/ HEIGHT
• MINIMUM DESCENT ALTITUDE/ HEIGHT

INSTRUMENT APPROACH PROCEDURES
• ATIS
• Aircraft Approach Categories
• Entry Into Holding Pattern
• Speed Limitations
• Minimum Sector Altitude (MSA)
• Minimum Holding Altitude (MHA)
• Obstacle Clearance Altitude/ Height
• Charted Altitudes for Precision App
Procedures - ( ILS, LOC, VOR, DME,
NDB ,VDF, ASR ,PAR )

AIRCRAFT APPROACH CATEGORIES
• AIRCRAFT ARE CATEGORISED BASED ON THEIR SPEED
AT THRESHOLD (V at). THESE SPEED RANGES ARE
ASSUMED FOR CALCULATION OF AIRSPACE AND
OBSTACLE CLEARANCE FOR EACH PROCEDURE
AIRCRAFT CATEGORY V at (K)
A Less Than 91
B 91- 120
C 121-140
D 141-165
E 166-210

Entry Into Holding Pattern
(Left Hand Hold )
• DIRECT ENTRY
• PARALLEL ENTRY
• OFFSET ENTRY
D
I
R
E
C
T
S
E
C
T
O
R
PARALLEL
ENTRY
SECTOR
OFFSET ENTRY
SECTOR 70º
110º

SPEED LIMITATIONS
LEVELS
Altitudes or Flt Lvl
Depending on Alt Setting
NORMAL
CONDITIONS
TURBULENCE
CONDITIONS
Up to and Inclusive 4250 M
(14000 Ft )
425 Km/h (230 K)
315 Km/h (170 K)
(For Cat A & B A/C)
520 Km/h (280 K)*
*Prior ATC Clearance
Required
315 Km/h (170 K)
(For Cat A & B A/C)
ABOVE 4250 M (14000 Ft) TO
6100M (20000 Ft) (Inclusive)
445 Km/h (240 K)
Wherever Possible
520 Km/h should be
used for airway Holds
520 Km/h (280 K)
0.8 Mach Whichever is
less
ABOVE 6100 M (20000 Ft) TO
10350 M (34000 Ft) (Inclusive)
490 Km/h (265 K)
Wherever Possible
520 Km/h should be
used for airway Holds
520 Km/h (280 K)
0.8 Mach Whichever is
less
ABOVE 10350 M (3400000 Ft) 0.83 Mach 0.83 Mach

Minimum Sector Altitudes
• These are the altitudes which would provide the
necessary vertical clearance above the terrain/
obstacles in the respective circle

MINIMUM SECTOR ALTITUDE
3200 FEET WHEN APPROACHONG
ON HEADING 090 DEG TO300DEG
AND
3700 FEET FROM HEADING 300 DEG
TO 090 DEG

MINIMUM HOLDING ALTITUDE
• MHA – IT IS THE LOWEST ALTITUDE
SPECIFIED FOR EACH HOLDING PATTERN
• OBSTACLE CLEARANCE ALTITUDE/
HEIGHT:
• CHARTED ALTITUDES FOR PRECISION
APP PROCEDURES -

INST. APP. PROCEDURES
• Non-Precision Approach Procedures
• Straight in Approach, Circling Approach
• Approach Segments
• Initial Approach Fix
• Intermediate Approach Fix
• Final Approach Fix
• Step Down Fix
• Landing Minima, Decision Altitude/ Height
• Minimum Descent Altitude/ Height

INST. APP. PROCEDURES
• Visibility/ RVR Minima
• Missed Approach Point
• Missed Approach Procedure
• Diversionary Procedure- Operational
Control

Period 51&52
POINT OF NO RETURN (PNR)
• DEFINITION
• IMPORTANCE AND USE
• CALCULATION OF DISTANCE AND TIME TO PNR
(BY FORMULA AND BY USING NAV COMPUTER)
• EFFECT OF CHANGE OF WIND VELOCITY ON POSN
OF PNR
• EFFECT OF ENGINE FAILURE
• LAST TIME TO DIVERT TO ALTERNATE
• PRACTICE PROBLEMS ON PNR

Period 53&54
CRITICAL POINT (CP)
• DEFINITION
• IMPORTANCE AND USE
• CALCULATION OF DISTANCE AND TIME TO CP
(BY FORMULA AND BY USING NAV COMPUTER)
• CRITICAL POINT FOR AERODROMES NOT FALLING ON THE
ROUTE
• EFFECT OF CHANGE OF WIND VELOCITY ON POSITION OF CP
• PRACTICE PROBLEMS ON CP

CRITICAL POINT (CP)
• Definition
• Importance and Use
• Calculation of Distance and Time to CP
(By Formula and by Using Nav Computer)
• Critical Point For Aerodromes Not Falling
on the Route
• Effect Of Change of Wind Velocity on
Position of CP

CP
• THE PILOT SOMETIMES HAS TO DECIDE ON THE
BEST COURSE OF ACTION IN THE SITUATIONS
WHICH DEVELOP IN THE AIR. FOR EXAMPLE IN
CASE OF AN EMERGENCY, LIKE ONE ENGINE
FAILURE IN A TWIN/ MULTI ENGINE AIRCRAFT,
THE NEED IS TO LAND AS QUICKLY AS
POSSIBLE. HENCE HE HAS TO DECIDE, WHETER
TO PROCEED TO DESTINATION OR RETURN TO
THE STARTING POINT
• CRITICAL POINT IS THAT POINT ON THE TRACK
FROM BASE “A” TO DESTINATION “B” FROM
WHERE IT TAKES THE SAME TIME TO PROCEED
TO “B” AS TO RETURN TO “A”. IT IS AN EQUI-
TIME POINT.

CP
• IN THE AIR TIME IS ALWAYS AT A
PREMIUM. TO HELP US TO SAVE TIME
AND TO BE ABLE TO TAKE A QUICK
AND OBJECTIVE DECISION, PRE-
FLIGHT PREPARATION INCLUDES THE
CALCULATION OF CRITICAL POINT
BETWEEN THE BASE AND
DESTINATION AS WELL AS BETWEEN
BASE AND A DIVERSION OR A
DIVERSION AND THE DESTINATION.

CP - CALCULATION
A B
D NM
X
CPX NM
LET “O” BE THE G/S OUT (A TO B)
AND “H” BE THE G/S HOME (B TO A)
LET “X” BE THE DIST FROM A TO CP
Therefore, Dist From CP To B = D-X
By Definition
Time From CP To A = Time From CP To B
i.e. X = D-X or OX = H(D-X)
H O
So, OX+HX = DH i.e X(O+H) = DH
Therefore, X = D H
O+H

CP
• TIME TO CP Will Be,
DIST TO CP = X
G/S OUT O
• EXAMPLE
• DIST A To B = 400 NM
• G/S OUT “O” = 160 K
• G/S HOME “H” = 200 K
• THEN, DIST TO CP X = 400 x 200
I60 + 200
i.e. 80000/360 = 222 NM
• And Time To CP = 222 / 160 = 83.5 Min
i.e. 1 hr 23.5 Min

CP- ON MORE THAN SINGLE LEG ROUTES
• ON A ROUTE , A To B, To C, To D
Route Track Dist W/V G/S TIME CUM
TIME
A-B
B-A
350
170
273
273
330/25 137
183
2:00
1:29
B-C
C-B
045
225
356
356
330/25 154
166
2:19
2:09
C-D
D-C
080
260
127
127
330/25 166
154
0:39
0:30
TAS=180 RED TAS= 160

• GIVEN
• A - B 230 NM H/W COMP 20 Kts
• B – C 140 NM H/W COMP 10 Kts
• C – D 330 NM T/W COMP 15 Kts
• FULL TAS = 200 Kts , RED TAS = 180
Kts
• CALCULATE DISTANCE AND TIME TO
CRITICAL POINT.

LEG TR W/V HDG TAS
*
G/S(
O)
DIST/
CUM
DIST
TIME
/CUM
TIME
LEG TR W/V HDG TAS
*
G/S
(H)
DIST/
CUM
DIST
TIME/
CUM
TIME
A-B
B-C
C-D
CP CALCULATION
DIST TO CP:………………………
X=DH (Treat This CP as Reporting Point
O+H
Time to CP= X
Normal G/S Out
*Use revised TAS as per Contingency Planned. Generally Engine Failure
D-E
E-F
F-G

CP CALCULATION
LEG TR W/V HDG TAS
*
G/S
(O)
DIST/
CUM
DIST
TIME
/CUM
TIME
LEG TR W/V HDG TAS
*
G/S
(H)
DIST/
CUM
DIST
TIME
/CUM
TIME
A-B 020 050/
25
180 77 B-A
B-C 050 050/
25
180 132 C-B
C-D 075 050/
25
180 167 D-C
D-E 045 075/
30
180 258 E-D
E-F 015 075/
30
180 132 F-E
F-G 025 075/
30
180 87 G-F
X=DH (Treat This CP as Reporting Point
O+H
Time to CP= X =……………
Normal G/S Out

CP CALCULATION
LEG TR W/V HDG TAS
*
G/S
(O)
DIST/
CUM
DIST
TIME
/CUM
TIME
LEG TR W/V HDG TAS
*
G/S
(H)
DIST/
CUM
DIST
TIME
/CUM
TIME
A-B 275 260/
70
400 332 473 1:25 B-A 260/
70
473 400 468 473 1:01
B-C 245 260/
70
400 332 512 1:33 C-B 260/
70
512 400 468 512 1:06
C-D 220 260/
70
400 350 627 1:47 D-C 260/
70
260/
70
627 400 450 627 1:24
D-E E-D
E-F F-E
F-G G-F
X=DH (Treat This CP as Reporting Point)
O+H
Time to CP= X =……………
Normal G/S Out

POINT OF NO RETURN (PNR)
• Definition
• Importance and Use
• Calculation of Distance and Time to PNR
(By Formula and by Using Nav Computer)
• Effect of Change of Wind Velocity on Posn
of PNR
• Effect of Engine Failure
• Last Time To DIVERT to Alternate

POINT OF NO RETURN
(Also Called POINT OF SAFE RETURN)
• DEFINITION: IT IS THAT POINT ON THE TRACK
FROM BASE TO DESTINATION UPTO WHICH AN
AIRCRAFT CAN FLY AND RETURN TO THE
STARTING POINT WITHIN THE SAFE ENDURANCE
OF THE AIRCRAFT
BASE
• •DESTINATION
X
POINT OF SAFE RETURN
Distance = X NM
IF G/S OUTBOUND =O
AND G/S INBOUND =H
THEN X/O + X/ H = SAFE END

PNR / PSR
• X + X = P
O H
Where , X is the distance from base to PNR
O is the G/S out
H is the G/S home
and P is the safe endurance
MULTIPLYING Both Sides By OH, we have
XH+XO = POH or X( O+H ) = POH
THEREFORE, X = POH
O+H

• EFFECT OF CHANGE OF WIND VEL ON PNR
• IN NIL WIND CONDITIONS,
G/S OUT=G /S HOME
• HENCE TIME OUTBOUND = TIME INBOUND
• SO DIST TO PNR = ½ P x O
• INCASE OF HEAD WIND/TAIL WIND ON THE OUTBOUND
LEG, THE PNR WILL ALWAYS SHIFT TOWARDS THE BASE.
Why ?
• EXAMPLE: LET P BE 4 HOURS, TAS IS 200K
• IN NIL WIND THE PNR WILL BE 2x200=400nm
• INCASE OF A 50K HEAD WIND ON OUTBOUND, O = 150 and
H = 250
• THEREFORE DIST TO PNR= 4x150x250 = 375 nm
150+250
• INCASE OF A TAIL WIND ON OUTBOUND ALSO PNR WILL
BE 4x250x 150 = 375 nm
250+150

CP/PNR PRACTICE QUESTION
• Q.1.
GIVEN, TAS=200 KTS, Engine out
TAS = 160 KTS
• ROUTE :
BAGHDAD – BASRA TR 115º (T), DIST 170NM, W/V 180/20 KTS
BASRA-KUWAIT TR 178 º (T), DIST 110NM, W/V 230/30 KTS
KUWAIT-BAHRAIN TR 129 º(T), DIST 147NM, W/V 250/15 KTS
• CALCULATE ETA CP if ATD
BAGHDAD is 1115 Z

• Q1-A
• FULL TAS = 350
• RED TAS= 300 K
• A – B TR/DIST 350/297 W/V 140/25
• B – C 040/335 100/25
• CALCULATE DIST AND TIME TO CP
• A - B G/S OUT = 321 HOME = 279
• B – C 288 312
•

Q.2. An aircraft has to fly a single leg route of 1000NM.
The cruising TAS is 480KTS and Engine out TAS is
350 KTS. Track is 120º(T) and average wind velocity
is 090/50.
Determine:
• Distance and Time to CP.
• Safe Endurance (excluding use of reserve fuel)
•
• Distance to PNR.
Assume that total fuel capacity is 15,600 kgs,
consumption at 480 Kts = 3150 kgs/hr, fuel reserve to
be carried are holding fuel of 50 minutes at cruising
consumption plus 15% of total fuel required. Ignore
climb and descent for all calculations.

Q.3. Given TAS is 480 KTS, Engine out TAS
is 380 KTS
• Route:
FROM-TO TRACK DIST.
W/V
DAR-ES-SALAAM-MAURITIUS 137 º 1441NM 140/30
MAURITIUS-COCO ISLANDS 080 º 2305NM 100/45
COCO ISLANDS- JAKARTA 060 º 693NM 170/25
• CALCULATE TIME TO CP.

• Q.4
AN AIRCRAFT IS TO FLY FROM ‘A’ TO
‘B’ ON A TRACK OF 280(T), DISTANCE 959
NM, MEAN TAS 230 Kt, W/V FOR THE FIRST
430 NM IS 200/50, AND 260/65 FOR THE
REMAINING DISTANCE. FUEL ON BOARD
IS 26,500 Kg, 3100 Kg TO BE HELD IN
RESERVE. CONSUMPTION IS 3400 Kg/Hr.
GIVE THE TIME AND DISTANCE TO:
(a) POINT OF NO RETURN/ PSR
(b) CRITICAL POINT/ PET/ ETP
ASSUMING
ENGINE FAILURE AT THE CP AND A
REDUCED TAS OF 190 Kt

SOLUTIONS
A
B
929 NM
X
430 NM
529 NM
G/S
O 2I7
H 232
G/S
O 167
H 291
200/50
260/65 Q.4

• Q.5
• GIVEN:
MAX TAKE OFF WEIGHT 61000 Kg
WEIGHT (No Fuel and No P’Load) 37000 Kg
TAS 410 Kt
DISTANCE 2250 NM
CONSUMPTION 2800 Kg/Hr
RESERVE (Assume Unused) 3200 Kg
HEADWIND Component 40 Kt
• DETERMINE:
(a) Maximum Payload That Can Be Carried
(b) Time and Distance to CP
(c) Time and Distance to PNR
(a) 3773 Kgs (b) 3:20 1235 NM (c)

• Q.6
• AN AIRCRAFT IS TO FLY FROM ‘A’ TO ‘B’ VIA
‘X’ AND ‘Y’ ; ROUTE DATA IS AS GIVEN:
Stage Wind Component (Kt) Distance(NM)
‘A’ to ‘X’ +20 400
‘X’ to ‘Y’ +15 630
‘Y’ to ‘B’ +25 605
Mean TAS 500 Kt (4 Eng) & 435 Kt (3 Eng)
Mean Fuel Cons 5300 Kg/Hr ( 4 Engines ) &
4100 Kg/Hr ( 3 Engines )
Fuel On Board ( Including Reserve 5500 Kg, unused)
30,000 Kg
Calculate the Time and Distance to the Point of
Safe Return from departure ‘A’, the RETURN flight
to ‘A’ to be made on 3 Engines

• Q.7
• ON A TRIP FROM ‘A’ TO ‘C’ VIA ‘B’, AN AIRCRAFT IS
ORDERED IN THE EVENT OF TURNING BACK,TO
PROCEED TO ITS ALTERNATE ‘D’ VIA ‘B’. TAS ON 4
ENGINES IS 500 Kt, AND ON 3 ENGINES IS 420 Kt. Route
Details Are:
From To Wind Component Distance
‘A’ ‘B’ -25 Kt 565 NM
‘B’ ‘C’ -45 Kt 900 NM
‘B’ ‘D’ +30 Kt 240 NM
• (a) IF THE RETURN FROM CRITICAL POINT IS MADE ON
THREE ENGINES, GIVE THE TIME AND DISTANCE ‘A’
TO THE CRITICAL POINT BETWEEN ‘C’ AND ‘D’.
• (b) Fuel On Board 38000 Kg, Cons 6300 Kg/Hr, Reserve
(Assume Unused) 6500 Kg, and the Whole Flight Is
Made On 4 Engines, What Is the Distance From ‘A’ To
The Point Of Safe Return to ‘D’

Q.7
A B
C
D
565 NM
900 NM
240NM
O 475 Kt
O 455 Kt
H
465 Kt
O450Kt

Period 55&56
SOLAR SYSTEM AND TIME
• RELATIONSHIP BETWEEN LONGITUDE AND TIME
• STANDARD TIME, LOCAL MEAN TIME & UTC
• INTERNATIONAL DATE LINE
• SUN RISE/ SUN SET-
• DEFINITION, VARIATION OF TIMES OF PHENOMENA WITH
LATITUDE, HEIGHT AND WITH DECLINATION OF THE SUN
• EXTRACTION OF TIMES OF PHENOMENA FROM AIR ALMANAC
• TWILIGHT-
DEFINITION
VARIATION OF PERIOD OF TWILIGHT WITH LATITUDE,
DECLINATION OF SUN AND HEIGHT OF AIRCRAFT
• MOON RISE/ MOONSET
DEFINITION
TABULATION IN AIR ALMANAC

SOLAR SYSTEM AND TIME
• Relationship Between Longitude and Time
• Standard Time, Local Mean Time & UTC
• International Date Line
• SUN RISE/ SUN SET-
Definition, Variation of Times Of
Phenomena with Latitude, Height and
With Declination of the Sun
Extraction of Times of Phenomena From
Air Almanac

• MEASUREMENT OF TIME IS BASED ON :
• EARTH’S ROTATION – OWN AXIS
• ROTATION AROUND THE SUN
( MOVEMENT OF THE SUN IN THE GALAXY AND THE GALAXY
ITSELF IN THE UNIVERSE HAVE A NEGLIGIBLE EFFECT ON
MEASUREMENT OF TIME)
• PERIHELION ( 04 JAN ) 91.4 M Miles
• APHELION (03 JULY ) 94.6 M Miles
( MEAN DIST 93 M Miles )

• THE SEASONS:
• PREDOMINANT CAUSE – INCLINATION
OF EARTH’S AXIS TO ITS ORBITAL
PLANE AT 66.5°
• THIS CAUSES THE DECLINATION OF THE
SUN TO CHANGE FROM
EQUATOR( LAT 0°) - Mar 21
Tropic of Cancer (Lat 23.5° N) -Jun 21
EQUATOR( LAT 0°) Sept 21
Tropic of Capricorn (Lat 23.5° S)- Dec 21

March21
Spring Equinox
September 21
Autumn Equinox
June 21
Summer Solstice
December 21
Winter Solstice
DECLINATION OF THE SUN
23.5º
23.5º
20º
20º
10º
10º
J F M A M J J A S O N D J
Largest
Change
Smallest Change

DAYS AND YEARS
• CIVIL DAY – Should be related to hours of daylight and
darkness and be of constant duration
• SIDERIAL DAY – Measured with respect to a fixed point in
space - a distant star
Not suitable as it is not related to daylight
• APPARENT SOLAR DAY- Measured with respect to real or
apparent sun
Related to daylight but not constant length
Apparent Solar DAY is longer than Siderial Day
• MEAN SOLAR DAY – Mean Sun is an imaginary sun which
appears to move around the earth at a constant speed equal to
the average speed of the REAL SUN
• Mean solar day is measured in relation to the MEAN SUN, IS
CONSTANT IN LENGTH AND IS RELATED TO HOURS OF
DAYLIGHT AND DARKNESS
• Maximum diff between mean time and real sun time is 16 min
in mid November and 14 minutes in mid February

Z
Z
Z
Parallel Light Rays
}Siderial
day
Apparent Solar Day
A
B
C

YEAR
• SIDERIAL YEAR – Time taken by the Earth to
complete one orbit of the Sun measured against a
distant Star – 365 Days 6 Hrs
• TROPICAL YEAR – Time interval between two
successive crossings of the Equator by the Sun from
South to North (Declination = 0 Deg). It is the
length of one cycle of Seasons – 365 Days, 5 Hrs 48
Min 45 Sec.
• CALENDER YEAR – Normally 365 days, kept in step
with Tropical Year by adding a day once in 4 Yrs
(LEAP year) and a fine adjustment by skipping 3 leap
yrs in 400 yrs (when first two nos. of century not
divisible by 4 - year is not a Leap Year)

HOUR ANGLE
• HOUR Angle of a celestial body is defined as
the arc of the Equinoctial intercepted
between the meridian of a datum (Greenwich
or the observer) and the Meridian of the
Body, measured Westward 0 to 360 Deg.
• EARTH SPINS 360°in 24 Hours
• HENCE in ONE Hour it Spins 15°
In 4 minutes , 1°
In 1 Minute , ¼ ° ie. 15’
In 4 Seconds ,1 Minute of rotation

TIME
LOCAL MEAN TIME
STANDARD TIME
IST
GMT
UTC
ZONE TIME

CENTRAL MERIDIAN FOR THE ZONE
1
8
0
W
1
6
5
W
1
5
0
W
1
3
5
W
1
2
0
W
1
0
5
W
9
0
W
7
5
W
6
0
W
4
5
W
3
0
W
1
5
W
0° 1
5
E
3
0
E
4
5
E
6
0
E
7
5
E
9
0
E
1
0
5
E
1
2
0
E
1
3
5
E
1
5
0
E
1
6
5
E
1
8
0
E
Y X W V U T S R Q P O N Z A B C D E F G H I K L M
Z O N E
Z O N E N U M B E R
+
1
2
+
1
1
+
1
0
+
9
+
8
+
7
+
6
+
5
+
4
+
3
+
2
+
1 0
-
1
-
2
-
3
-
4
-
5
-
6
-
7
-
8
-
9
-
1
0
-
1
1
-
1
2
ZONE TIME

GM
000
15°E
30E
45E
60E
75E
90E
105E
120E
135E
150E
165E
NP
A
B
c
D
E
F
G
H
I
K
L
M
ZN
O
P
Q
R
S
T
U
V
W
X Y
165W
150W
135W
120W
105W
90W
75W
60W
45W
30W
15W
097 ½ E
082 ½ E
067 ½ E
052 ½ E
037 ½ E
022 ½ E
112 ½ E
127 ½ E
142 ½ E
157 ½ E
172 ½ E180E/W
MY
NP

• TWILIGHT-
Definition
Variation of Period Of Twilight with
Latitude
Declination of Sun
Height of Aircraft
• MOON RISE/ MOONSET
Definition
Tabulation in Air Almanac

SENSIBLE/ VISIBLE HORIZON
EFFECT OF ATMOSPHERIC REFRACTION AND
SUN’S SEMI DIAMETER OF SUN

NAVIGATION INSTRUMENTS,
MAGNETISM
&
COMPASSES

• Period 57&58
MAGNETISM &COMPASSES
• INTRODUCTION
• TERRESTRIAL MAGNETISM, MAGNETIC POLES
• MAGNETIC MERIDIAN
• MAGNETIC VARIATION: ISOGONAL AND AGONIC LINES
• ANGLE OF DIP: ISOCLINAL AND ACLINAL LINES
• HORIZONTAL AND VERTICAL COMPONENTS MAGNETIC
EQUATOR
• REGULAR AND IRREGULAR CHANGES IN THE EARTH’S
MAGNETIC FIELD
• LOCAL IRREGULARITIES IN EARTH’S MAGNETIC FIELD

GENERAL
• Terrestrial Magnetism, Magnetic Poles
• Magnetic Meridian
• Magnetic Variation: Isogonal and Agonic
Lines
• Angle Of Dip: Isoclinal and Aclinal Lines
• Horizontal and Vertical Components
Magnetic Equator
• Regular and Irregular Changes in the Earth’s
Magnetic Field
• Local Irregularities In Earth’s Magnetic Field

Period 59&60
DIRECT READING COMPASS
• REQUIREMENTS OF MAGNETIC COMPASS
• UNRELIABILITY OF COMPASS INDICATIONS DURING
TURNS AND ACCELERATION/ DECELERATION
• COMPASS AND MAGNETIC HEADINGS
• EFFECT OF CHANGE OF GEOGRAPHIC POSITION
AND MAGNETIC MATERIAL CARRIED IN THE AIRCRAFT
• DEVIATION AND ITS APPLICATION
• KNOWLEDGE OF COEFFICIENTS A,B AND C
• KNOWLEDGE OF PREPARATION OF COMPASS CARD
• IMPORTANCE AND PROCEDURE OF COMPASS SWING
ON THE GROUND
• OCCASIONS FOR COMPASS SWING ON THE GROUND

DIRECT READING COMPASS
• Requirements of Magnetic Compass
HORIZONTALITY
Directive Force H, is Horizontal. So for best results, the System must
be maintained HORIZONTAL. How? C of G Kept BELOW Pt of
Pivot
SENSITIVITY
For Higher accuracy the system must be capable of detecting even
small changes in Earth’s Mag. Fd. That is it must be very sensitive.
How? i) By using IRIDIUM TIPPED PIVOT in a JEWELLED CUP
ii) By Lubricating the Pivot with liquid filled in Compass Bowl
iii) By reducing effective weight of the Mag. System
APERIODICITY (Should NOT Oscillate, should come to rest quickly)
How i) By using several short , powerful magnets
ii) By using DAMPING WIRES which will dampen any
oscillations due to the resistance by the liquid

• THE COMPASS LIQUID (Desired Properties)
• Low Coefficient Of Expansion
• Low Viscosity
• Transparency
• Low Freezing Point
• High Boiling Point
• Non-corrosive
Dimethyl Siloxane Polymer – meets most
of these requirements.

• Unreliability of Compass Indications
During Turns and Acceleration/
Deceleration
• Compass and Magnetic Headings
• Effect of Change of Geographic Position
and Magnetic Material Carried in the
Aircraft
• Deviation and its Application

TURNING AND ACCELERATION ERRORS
• Aircraft on Northerly Hdg
Turning right
N
S
N
S
Centrifugal Force at Pivot –F
Inertia at C of G – F’
F F’ Set up Clockwise Moment
Result: Compass Turns in the
Direction of Turn
So LESSER Turn Indicated
What Happens on a Southerly Course?
What Happens on an Easterly Course?
What Happens on an Westerly Course?
F
F’
C of G
Point of Pivot
C of G

• ACCELERATION ERRORS
N
S
C of G
Pivot
AIRCRAFT ON AN EASTERLY HDG
AND ACCELERATING
ACCELERATION FORCE ACTS
AT THE PIVOT
INERTIA ACTS AT THE C OF G
THE TWOFORCES SET UP A MOMENT
RESULT : COMPASS SYSTEM TURNS
IN A CLOCKWISE DIRECTION
i.e. HEADING REDUCES
AIRCRAFT APPEARS TO TURN TOWARDS
NORTH
What Happens on an Easterly course?
What Happens on a Northerly course?
What Happens on a Westerly course?
What Happens in case of a deceleration?
ACCLNINERTIA

• EFFECT OF CHANGE OF GEOGRAPHIC
POSITION
Higher the Lat,
More Dip, Reduction
in H, Increase in Z
Causing more tilt
Errors more pronounced
• EFFECT OF MAGNETIC MATERIAL
CARRIED IN THE AIRCRAFT
Will affect the compass system
Reducing effect of H, May cause
Deviation
T
H
Z
T”Z”
H”

DIRECT READING COMPASS - ERRORS
TURNING AND ACCELERATION ERRORS
SCALE ERRORS
ALIGNMENT ERROR
CENTERING ERROR
PARALLAX ERROR

ADVANTAGES/ DISADVANTAGES OF DR COMPASSES
ADVANTAGES
SIMPLE, LIGHT WEIGHT, LESS COSTLY,
DO NOT REQUIRE ELECTRICAL POWER
DISADVANTAGES
SUFFER FROM ERRORS
ACCURACY
RESTRICTED AC MANEOUVRES
AFFECTED BY A/C MAGNETISM
NO REPEATER OR TORQUE OUTPUT
TO OTHER SYSTEMS
REDUCED “H” IN HIGHER LATITUDES

Period 61&62
REMOTE READING COMPASS
• GENERAL PRINCIPLES
• BASIC USE: PRESENTATION OF HEADING
• ADVANTAGES OVER DRC

SIMPLE FLUX VALVE
N
N
S
S
̃
AC
Induced Voltage
Primary Windings
Secondary Windings
Core A
Core B
CONSTRUCTION
TWO IDENTICAL SOFT IRON CORES HAVE WINDINGS
SUCH THAT AN AC INDUCES OPPOSITE POLARITY IN
THE CORES.
THE TWO CORES ARE WOUND WITH A COMMON
SECONDARYAND THE SECONDARIES PICK UP THE
TOTAL RESULTANT FLUX OF THE TWO CORES
~

FLUX VALVE – SIMPLIFIED VIEW

EARTH’S FIELD “H”
MAG HDG 000 ° 090° 180 ° 270 ° 360°
000°
MAX NIL MAX NIL MAX
FLUX INDUCED IN A CORE AS THE ANGLE IS
VARIED

Core A Core B
Output Voltage
+
0
-
Resultant Voltage induced in
Secondary Windings when H= 0
Core B
Core A
A
C
F
L
U
X

+
0
--
Earth’s Mag
Fd H
Saturation level
Core A Core B
Resultant Flux in
Secondary Windings
A
C
Resultant Voltage induced in
Secondary Windings when H is not 0
Core A
Core B
F
L
U
X

ONE OF THE THREE SPOKES OF
THE SPERRY FLUX VALVE

SIGNAL SELSYN
DATA SELSYN
MASTER
INDICATOR
AMPGYRO
UNIT
PRECESSION FOLLOW UP
GYRO
BEVEL GEARS
HORIZONTAL
VERTICAL
400
CPS
AC
400 CPS
AC
GEAR
TRAIN
TO
REPEATERS
ROTOR
Precession
Coils
Center
Shaft
Detector Unit
FOLLOW UP
MOTOR
Varn Setting
Control
RIC (SCHEMATIC)

REMOTE INDICATING COMPASS
(THE SLAVED GYRO COMPASS)
• COMPONENTS
THE DETECTOR UNIT
GYRO UNIT- ANNUNCIATOR, SYNC KNOB
AMPLIFIER UNIT
CORRECTOR CONTROL BOX
REPEATER SYSTEM

AIRCRAFT MAGNETISM
Magnetic Materials
Non Magnetic Materials
Hard Iron (Permanent)
Soft Iron (Temp Magnetised)
Magnetisation methods
Stroking
Placing in a Strong Magnetic Field
Electric Field
Aircraft Magnetic Materials get Magnetised-
Why?

• Aircraft Magnetism
Hard Iron Soft Iron
Permanent Temp – Only in
Does not Change presence of Mag Fd
With Hdg Effect Changes
with Ch in Hdg

• DEVIATION:
Is the angular difference between the
Magnetic North and the Compass North
and is termed E or W depending on
whether the Compass North lies to the E
or W of the Magnetic North
Hdg (C) +/- Devn E/W = Hdg(M)
DEVN EAST, COMPASS LEAST
DEVN WEST, COMPASS BEST

AIRCRAFT PERMANENT MAG
• HOW IS IT ACQUIRED?
• WHAT EFFECT DOES IT HAVE?
• HOW DO WE ANALYSE/ CORRECT FOR
IT?
• EFFECT OF CHANGE IN HDG?
• ASSUMPTIONS - P, Q, R

P – F& A COMPONENT OF A/C
PERMANENT MAGNETISM
RESULTANT FIELD
NIL DEVN
N
E
S
W
000°
045°
09O°
180°
270°
315°
225°
135°
EFFECT OF +P
ON COMP DEVN

Q – ATHWARTSHIP COMPONENT
OF A/C PERMANENT MAGNETISM
RESULTANT FIELD
MAX DEVN E
N
E
S
W
000°
045°
09O°
180°
270°
315°
225°
135°
EFFECT OF +Q
ON COMP DEVN
MAX DEVN W
0
DEVN
0
DEVN

• Coeff A= Devn on(N+E+W+S+NE+NW+SE+SW)
8
• Coeff C= Devn on N- Devn on S
2
• Coeff B= Devn on E- Devn on W
2
• Knowledge Of Preparation of Deviation Card
• Importance Of Compass Swing
• Procedure
• Occasions for Compass Swinging on the
Ground

COMPASS SWING PROCEDURE
• Check comp for “S”
• TAKE A/C TO SUITABLE SITE( sw base)
• ENSURE FLT CONTROLS, Engs, Rad/Elect Circuits – ON
• PLACE A/C ON Hdg ‘S(M)’- Note Devn…(i)
• PLACE A/C ON Hdg ‘W(M)’ - Note Devn…(ii)
• PLACE A/C ON Hdg ‘N(M)’- Note Devn…(iii)
• CALCULATE Coeff ‘C’ ….[ iii –i ]/2 ApplyTo
Compass reading and Correct (No sign change)
• PLACE A/C ON Hdg ‘E’ - Note Devn…(iv)
• CALCULATE Coeff ‘B’ ….[ iv –ii ]/2 ApplyTo
Compass reading and Correct (No sign change)
• Carry out check swing on 8 Headings
• CALCULATE Coeff ‘A’ –Sum of Devns on all Hdgs
Devided by total number of Hdgs. Correct by moving
Lubber Line/ VSC/ Detector Unit as Appropriate

OCCASIONS FOR A COMPASS SWING
• WHENEVER THE A/C IS INITIALLY RECEIVED
• PERIODICAL - EVERY THREE MONTHS OR AS
SPECIFIED IN THE C of A
• AFTER A MAJOR INSPECTION
• AFTER STANDING ON ONE HDG FOR MORE THAN
FOUR WEEKS
• ANYTIME THERE IS A MAJOR COMPONENT
CHANGE
• ANYTIME THERE IS A PERMANENT MAJOR
CHANGE IN LATITUDE
• ANYTIME THE A/C IS STRUCK BY LIGHTNING
• ANYTIME THE ACCURACY OF THE COMPASS IS
SUSPECT
•

• QUESTION
• The results of a compass swing are as follows:
• Hdg (C) Hdg (M)
002 357
047 044
092 090
137 135
182 181
227 228
272 272
317 313
• Calculate Coeffs A, B & C
• What will you make the compass read on S & W
• Hdgs to correct for Coeff C/B ?
• What will you make it read on 313(M) to correct for A ?

0
0 1 2 3 EW 3 2 1 1 2 3 E W 3 2 1
X
X
X
X
X
X
X
X
X

RIC - ADVANTAGES
• DET UNIT INSTALLED REMOTELY SO LEAST
AFFECTED BY A/C MAGNETISM
• NO TURNING AND ACCLN ERRORS
• REPEATERS ARE POSSIBLE: FEED TO
OTHER EQPT POSSIBLE
• RIGIDITY OF THE GYRO IS USED TO OVER
COME THE T & A ERRORS WHILE THE GYRO
WANDER IS CONTROLLED BY KEEPING IT
ALIGNED WITH THE MAGNETIC MERIDIAN
WHICH IS BEING CONTINUOUSLY SENSED
BY THE DETECTOR UNIT (3 TO 5 DEG/ MIN)

GRID NAVIGATION
G/C TRACK ON POLAR STEROGRAPHIC OR LAMBERT’S CON.
Represented by a straight Line
But the problem is that due to convergence of longitudes the
True DIRECTION IS CONSTANTLY AND RAPIDLY CHANGING
30 W
GM 30 E

30 W
GM 30 E
GRID
NORTH
TRUE
NORTH
CONVERGENCE
is the angle
between GN and TN
termed E or W
depending on
whether TN lies
E OR W OF GN

CONVERGENCE
• IN NORTHERN HEMISPHERE CONV IS EAST WHEN
LONG IS WEST AND CONVERGENCE IS WEST
WHEN LONG IS EAST
• IN SOUTHERN HEMISPHERE IT IS THE SAME AS
THE LONGITUDE
• ITS VALUE IS SAME AS CHART CONVERGENCE. SO
ON A POLAR STEREOGRAPHIC WITH GRID NORTH
COINCIDING WITH GREENWICH MERIDIAN IT IS =
LONG E OR W ( WITH SIGN CHANGE IN NH)
• GRID DIR+ CONVERGENCE = TRUE DIR
• G C T V M D C
090(G) 45E 045(T) 20W 025(M) 3E 028(C)

GM
45 E
45 W
90 W
135 W
180 E/W
90 E
135 E
NP
A B

INSTRUMENTS
• PRESSURE INSTRUMENTS
Pressure Altimeter] Principal of op
ASI ] Basic Construction
VSI ]Use, Limitations &
Machmeter ] Errors

Period 63&64
PRESSURE INSTRUMENTS
 PRESSURE ALTIMETER
PRINCIPAL OF OP
BASIC CONSTRUCTION (SIMPLE, SENSITIVE,
SERVO)
CALIBRATION
USES, LIMITATIONS &
ERRORS
EFFECTS OF VARIATIONS IN TEMP AND PR
ALTIMETRY PROBLEMS

ALTIMETER
100 FEET
POINTER
1000 FEET
POINTER
SUB
SCALESUB
SCALE
SETTING
KNOB

SENSITIVE ALTIMETER
• ADDITIONAL
1000 FEET
POINTER
WARNING
FLAG-
YELLOW
DIAGONAL LINES
APPEAR BELOW
10000 FEET

PRESSURE ALTITUDE ERRORS
INSTRUMENT ERROR
PRESSURE ERROR
BAROMETRIC ERROR
TEMPERATURE ERROR
TIME LAG
BLOCKAGES

7 1 50
1010
1
2
3
4
5
6
7
8
9
0
FIVE DIGIT COUNTER
CROSS HATCHING
APPEARS IN PLACE OF
FIRST COUNTER WHEN
BELOW 10000 Ft
POWER FAILURE OR
MALFUNCTION
WARNING:
STRIPED FLAG APPEARS
IN WINDOW
POINTER COMPPLETES
ONE REVOLUTION PER
1000 FEET
SET PRESSURE
SERVO ALTIMETER DIAL

ADVANTAGES OF A
SERVO ALTIMETER
• VERY SENSITIVE – CAN PICK UP A CAPSULE
MOVEMENT AS LITTLE AS 0.0002Inches / Thousand
Feet GIVING AN ACCURACY OF ± 100Feet at 40000 Ft
• VIRTUALLY ELIMINATES TIME LAG
• ELECTRICAL SYSTEM – SO CORRN FOR PE CAN BE
MADE AND ALTITUDE ALERTING DEVICE CAN BE
INCORPORATED
• DIGITAL READOUT- LESS CHANCES OF MIREADING
• POINTER AVAILABLE – USEFUL TO ASSESS RATE OF
CHANGE OF HEIGHT SPECIALLY AT LOW LEVELS
• CAPABLE OF HEIGHT ENCODING - SSR

• Period 65&66
PRESSURE INSTRUMENTS
AIR SPEED INDICATOR(ASI)
• PRINCIPAL OF OPERATION
• BASIC CONSTRUCTION
• CALIBRATION
• USES, LIMITATIONS
• ERRORS
• IAS, RAS/CAS, EAS , TAS

AIR SPEED INDICATOR
• PRINCIPLE: P = D + S
• or D = P – S
• CONSTRUCTION:
• CALIBRATION : AS PER ISA
PD = ½ ρ. V² 1 + V²
4C²
PD IS THE DYNAMIC PRESSURE ρ IS THE AIR DENSITY
V IS THE IAS CIS THE SPEED OF SOUND

ASI ERRORS
• INSTRUMENT ERROR
• PRESSURE ERROR
POSITION OF STATIC VENT
AIRCRAFT SPEED
ANGLE OF ATTACK AND THE A/C MANEOUVRE
AERODYNAMIC STATE , i.e. POSN OF FLAPS, U/C
• DENSITY ERROR
• COMPRESSIBILITY ERROR
[1 + V² ]
[ 4C² ] i.e. COMPRESSIBILITY FACTOR
• BLOCKAGES
• RELATIONSHIP BETWEEN DIFFERENT SPEEDS
RAS = IAS ± PE ( Including Inst Error)
EAS = RAS+ COMPRESSIBILITY ERROR CORRN
TAS = EAS+ DENSITY ERROR CORRN

• Period 69&70
PRESSURE INSTRUMENT
MACHMETER
PRINCIPAL OF OP
BASIC CONSTRUCTION
CALIBRATION
USE, LIMITATIONS &
ERRORS
RELATIONSHIP BETWEEN IAS/TAS/MACH NO./
AND ALTITUDE/ TEMPERATURE
TAT/OAT,FAT – RAT (RAM RISE)

MACHMETER
• MACH NO. =. TAS i.e. V
LOCAL SPD OF SOUND C
• NEED: IN HIGH SPEED FLIGHT SHOCK
WAVES ARE LIABLE TO BE SET UP AS THE
SPEED APPROACHES THE SPEED OF
SOUND AND CERTAIN AERODYNAMIC
EFFECTS LIKE CONTROL
FLUTTER/CONTROL REVERSAL CAN
OCCUR. THESE EFFECTS OCCUR NOT AT
ANY FIXED TAS OR IAS BUT AT FIXED V/C
RATIO. MACHMETER CONTINUOUSLY
MEASURES THIS RATIO AND DISPLAYS IT
TO THE PILOT
• MCRIT- CRITICAL MACH NUMBER : IT IS THAT FREE
STREAM MACH NO. AT WHICH THE AIRFLOW OVER
SOME PART OF THE AIRCRAFT REACHES MACH -1

• PRINCIPLE: M = V/C
TAS - IS A FUNCTION OF P-S & ρ
SP OF SOUND (C): FUNCTION OF S &
ρ ρ , density being a common factor
EQUATION Becomes M = P-S
S
AIR SPEED CAPSULE MEASURES “P-
S”
ALTITUDE CAPSULE MEASURES “S”
MOVEMENT OF THE TWO CAPSULES
IS COMBINED TO GIVE THE RATIO
P-S
S

VERTICAL SPEED INDICATOR
• PRINCIPLE : MEASURES RATE OF CHANGE OF
PRESSURE TO INDICATE VERTICAL SPEED
• CONSTRUCTION : CAPSULE METERING UNIT,
TEMP/ PR Compensation
• ERRORS :
INSTRUMENT ERROR
TIME LAG ERROR
PRESSURE ERROR
MANOEUVRE INDUCED ERROR
BLOCKAGES

V S I
DIAL
POINTER
MECHANICAL
LINKAGE
METERING UNIT
CAPSULE
VERTICAL SPEED INDICATOR ( Schematic)
UP
DOWN

IVSI (INERTIAL- LEAD VSI)
 TO GET RID OF TIME LAG
 COSISTS OF TWO DASHPOTS, EACH WITH AN
INERTIAL MASS – PISTONS BALANCED BY
SPRINGS, ONE SPRING BEING STRONGER THAN
THE OTHER
 DURING CLIMB/DESCENT, ACCELERATION
PUSHES THE PISTONS UP OR DOWN RESULTING
IN INSTANTANEOUS READING OF CLIMB/
DESCENT
 AFTER A FEW SECONDS, EFFECT OF
ACCELEROMETER PISTON DIES OUT, BUT BY
THEN NORMAL VSI OPERATION IS EFFECTIVE
 ERRORS :INSTRUMENT AND PRESSURE ERRORS
NO LAG OR MANEOUVER INDUCED ERRORS
TURNING ERRORS

Period 71&72
GYROSCOPES
• PROPERTIES – RIGIDITY AND PRECESSION
• METHODS OF IMPROVING RIGIDITY
• RULES OF PRECESSION
• PRECESSION RATE
• REAL WANDER
• APPARENT WANDER
• TYPES OF GYROSCOPES

GYROSCOPES
• PROPERTIES – Rigidity And Precession
• Methods of Improving RIGIDITY
• Rules of Precession
• Precession Rate
• Real Wander
• Apparent Wander
• Types Of Gyroscopes

GYRO OPERATED INSTRUMENTS
• Description
• Principle of Operation
• Use and
• Limitations
OF
Direction Gyro Indicator
Artificial Horizon
Turn and Slip Indicator
Turn Coordinator

Period 73&74
DIRECTION GYRO INDICATOR
DESCRIPTION
PRINCIPLE OF OPERATION
USE AND
LIMITATIONS
LATITUDE NUT
DRIFT AND TOPPLE PROBLEMS

DRIFT DUE TO
EARTH’S ROTATION
ROTOR ALIGNED
WITH LOCAL
MERIDIAN
ө
өHDG
090°(T)
HDG
090°(T)
ONE HOUR LATER ROTOR
REMAINS POINTING IN THE
SAME DIRECTION
INDICATED HEADING IS 090, i.e LESS
THAN THE TRUE HEADING i.e.090+ өDeg
DI DRIFT
APPARENT DRIFT DUE
TO EARTH ROTATION

DRIFT DUE TO AIRCRAFT
CHANGE OF LONG
DRIFT DUE TO
EARTH’S ROTATION
INDICATED HEADING AFTER
ONE HOUR FLIGHT IN AN
EASTERLY DIRECTION LESS
THAN 090 DEG ANDLESS
THAN STATIONARY
AIR CRAFT
ROTOR ALIGNED
WITH LOCAL
MERIDIAN
Ф
Ф
ө
ө
өHDG
090°(T)
HDG
090°(T)
HDG
090°(T)
DI DRIFT
APPARENT DRIFT
DUE TO AIRCRAFT
MOVEMENT

• Period 75&76
ARTIFICIAL HORIZON
DESCRIPTION
USES AND
LIMITATIONS

ARTIFICIAL HORIZON
Indicating: (a) Level (b) Climb
(c) Descent
(a) (b) (c)

Period 77&78
GYRO OPERATEDINSTRUMENTS
• TURN AND SLIP INDICATOR
DESCRIPTION
USE AND
LIMITATIONS
•TURN COORDINATOR

TURN INDICATOR
• NEED: THE PILOT NEEDS TO KNOW AT AT
WHAT RATE THE AIRCRAFT IS TURNING
• RATE TURNS:
• RATE 1 TURN IS WHEN A/C TURNS
THRO’ 360 DEG IN TWO MINUTES
OR 180 DEG IN 0NE MINUTE

Period 79&80
AUTOMATIC FLIGHT CONTROL
SYSTEM
BASIC KNOWLEDGE OF OPERATION
AND USE

Period 81&82
INERTIAL NAVIGATION SYSTEM/
INERTIAL REFERENCE SYSTEM
• PRINCIPLE OF OPERATION &
• ITS USES

Period 83&84
• PROPERTIES OF RADIO WAVES
• NATURE OF RADIO WAVES
• DEFINITIONS
AMPLITUDE
CYCLE
FREQUENCY
WAVE LENGTH
• RELATIONSHIP BETWEEN WAVE LENGTH AND FREQUENCY
& THEIR CONVERSION
• FREQUENCY SPECTRUM
• POLARISATION
• PRINCIPLES OF RADIO TRANSMISSION
 GROUND WAVE PROPAGATION
FACTORS AFFECTING RANGE
DIFFRACTION
ATTENUATION
EFFECT OF TYPE OF SURFACE ON PROPAGATION
 RANGES OBTAINABLE AT DIFFERENT FREQUENCIES

PROPERTIES OF RADIO WAVES
• Nature of Radio Waves
• Definitions
Amplitude
Cycle
Frequency
Wave length
• Relationship Between Wave length and
Frequency & their Conversion
• Frequency Spectrum
• Polarisation

PHASE & PHASE DIFFERENCE
0 90 180 270 360
O N E C Y C L E
WAVE LENGTH ( DISTANCE)
λ
WAVES ARE
IN PHASE
WAVE LAGS
90 DEG / 180 DEG
A
M
P
L
I
T
U
D
E

Electro Magnetic Waves
Vertical PLANEHorizontal plane
POLARISATION VERTICAL

FREQUENCY BAND DESIGNATOR
Freq Band Name Abbr. Frequencies Wave Lengths
Very Low Freq VLF 3 – 30 KHz 100Km – 10 Km
Low Freq LF 30 – 300 KHz 10 Km – 1Km
Medium Freq MF 300 – 3000KHz 1 Km – 100M
High Freq HF 3 – 30 MHz 100M – 10 M
Very High Freq VHF 30 - 300 MHz 10 M – 1 M
Ultra High Freq UHF 300 – 3000 MHz 1M - 10Cm
Super High Freq SHF 3 - 30 GHz 10 Cm – 1Cms
Extremely High Freq EHF 30 – 300 GHz 1 Cm –1 mm

• Principles of Radio Transmission
Ground Wave Propagation
Factors Affecting Range
Diffraction
Refraction
Reflection
Attenuation
Fading
Effect of Type of Surface on Propagation
 Ranges Obtainable at Different
Frequencies

Period 85&86
SKY WAVE PROPAGATION
 IONOSPHERE
DEFINITION
VARIATION WITH TIME OF DAY,
SEASONS AND LATITUDE
 REFRACTION AND ABSORPTION WITHIN THE IONOSPHERE
 CRITICAL FREQUENCY / CRITICAL ANGLE
 SKIP DISTANCE AND DEAD SPACE
 PERFORMANCE AT DIFFERENT FREQUENCIES
DIRECT WAVE PROPAGATION
 FACTORS AFFECTING RANGE
 DUCT PROPAGATION

• Sky Wave Propagation
 Ionosphere
Definition
Variation With Time of Day,
Seasons and Latitude
Refraction and Absorption Within the
Ionosphere
Critical Frequency / Critical Angle
Skip Distance and Dead Space
Performance At Different Frequencies

• Direct Wave Propagation
Factors Affecting Range
Duct Propagation

MODULATION OF RADIO WAVES
• NEED FOR MODULATION
• AMPLITUDE MODULATION
• FREQUENCY MODULATION
• PHASE MODULATION
• PULSE MODULATION

DIRECTION FINDING / ADF
• PRINCIPLE
• ELEMENTS OF DF
• 180° AMBIGUITY AND ITS RESOLUTION
• NIGHT EFFECT REFRACTION
• QUADRANTAL ERROR
• COASTAL
• EFFECTS OF HIGH GROUND/ TERRAIN EFFECT
• RANGE AND ACCURACY
• AUTOMATIC DIRECTION FINDER
• PRINCIPLE OF OPERATION
• FREQUENCY BAND
• TUNING AND IDENTIFICATION
• LIMITATIONS
• USES – HOMING, TRACKING, & ORIENTATION

DIRECTION FINDING
ADF
• Principle: BEARING BY LOOP D/F
• Elements of DF
• 180° Ambiguity and Its Resolution
• Night Effect Refraction
• Quadrantal Error
• Coastal
• Effects of High Ground/ Terrain Effect
• Range and Accuracy

• NON DIRECTIONAL BEACON
(NDB)
A GROUND BASED TRANSMITTER WHICH TRANSMITS
VERTICALLY POLARISED RADIO WAVES AT A UNIFORM
SIGNAL STRENGTH IN ALL DIRECTIONS IN THE LF AND
MF BANDS
THE ADF EQUIPMENT IN THE AIRCRAF,T WHEN TUNED
TO THE SPECIFIC NDB FREQUENCY , INDICATES THE
DIRECTION FROM WHICH THE RADIO WAVES ARE
COMING i.e. THE DIRECTION OF THE NDB
A “CONE OF SILENCE” EXISTS OVERHEAD THE NDB
WHERE THE AIRCRAFT DOES NOT RECEIVE ANY
SIGNALS. THE DIA OF THE CONE INCREASES WITH
INCREASE IN HEIGHT

BEARING BY LOOP DIRECTION FINDING:
IF YOU PLACE ALOOP AERIALIN THE PLANE OF
A RADIO WAVE A VOLTAGE WILL BE PRODUCED
IN THE VERTICAL MEMBERS
MAX EMF
INDUCED
NO EMF
INDUCED

• IF THE LOOP IS ROTATED THE
VOLTAGE INDUCED WILL DECREASE
UNTIL IT IS ZERO WHEN

RELATIVE BEARING
INDICATOR
000
180
090270
030
060
120
150210
240
300
330
RBI

ADF
• FREQ BAND: 2OO – 1750 KHz
• EMISSION: NON AIA, NONA2A, A2A
• RANGE: 200 NM BY DAY(DO NOT USE OUTSIDE PROTECTED
RANGE) , 70 NM BY NIGHT
• FACTORS AFFECTING RANGE: Tx POWER,
FREQ, NIGHT EFFECT, EMISSION, TERRAIN
• ACCURACY: ± 5° (WITHIN PROTECTED RANGE)
• FACTORS:N/EFFECT, TERRAIN, STATIC, QE,
STN INTERFERENCE, ALIGNMENT
• FAILURE WARNING: NIL
• BFO: NON A1A –TUNING AND IDENTIFICATION
NON A2A – TUNING ONLY
A2A – BFO NOT TO BE USED

0365.5
FREQUENCY TEST
TONE
OFF
ADF
ANT
GAINOFF
ADF CONTROL UNIT
A
D
F

ADF
Frequencies : Allocated Freq 190-1750 KHz
Normally most NDBs 250-450 KHz
Types of NDBs: Locator - Low Powered 10-
25nm
Enroute – More power giving
ranges of 50nm-Hundreds of
miles
AIRCRAFT EQPT:
A LOOP AERIAL
A SENSE AERIAL
A CONTROL UNIT
A RECEIVER

ADF
• Emission Characteristics:
• ALL NDBs have 2 or 3 Letter Identification
• and two types of emission NON A1A and
NON A2A
• “NON” PART OF THE EMISSION IS UNMODULATED
CARRIER WAVE, WHICH WILL NOT BE DETECTED ON A
NORMAL Rx. SO A BFO IS PROVIDED ON ADF
EQUIPMENT. WHEN BFO IS “ON” IT PRODUCES AN
OFFSET FREQ in the receiver WHICH IN COMBINATION
WITH THE RECEIVED FREQ PRODUCES A TONE OF SAY
400 OR 1020 Hz
• “A1A” PART IS IS THE EMISSION OF AN INTURRUPTED
CARRIER WAVE WHICH REQUIRES THE BFO TO BE ON
FOR AURAL RECEPTION.
• “A2A” IS THE EMISSION OF AN AMPLITUDE
MODULATED CARRIER WHICH CAN BE HEARD ON A
NORMAL RECEIVER

ADF
• WHEN USING NON A1A Beacons - BFO‘ON’
For manual Tuning, Identification and
Monitoring
• WHEN USING NON A2A Beacons – BFO ‘ON’ For
Manual Tuning But Off For
Identification And Monitoring
PRESENTATION OF INFO
RBI - GIVES RELATIVE BEARING
RMI – RADIO MAGNETIC INDICATOR:
COMBINES RELATIVE BEARING INFO FROM THE
ADF WITH HEADING MAGNETIC

Relative
Bearing
000
030
330
060
090
300
120
180
270
150
240
210
ADF
Indicator

RELATIVE BEARING
INDICATOR
RMI
HDG(M)
000
180
090
270
030
060
120
150
210
240
300
330

Period 91&92
VOR (VERY HIGH FREQ OMNI RANGE )
• FREQUENCY BAND
• RANGE – LINE OF SIGHT
• TUNING AND IDENTIFICATION
• RANGE – LINE OF SIGHT RANGE CALCULATION
• USES
• ADVANTAGES
• ACCURACY AND RELIABILITY
• D VOR

VOR
• VHF OMNI-DIRECTIONAL RANGE – STD
SHORT RANGE NAV AID BY ICAO -1960
• GIVES 360 RADIALS, EACH 1° APART
STARTING FROM MAGNETIC NORTH AT VOR
LOCATION
• VHF AND HENCE VOR IS FREE FM STATIC
INTERFERENCE, NO SKY WAVES SO CAN BE
USED DAY AND NIGHT
• VOR FREQ CAN BE PAIRED WITH CO-
LOCATED DME GIVING INSTANTANEOUS
Rho-Theta FIX

• VOR
• Frequency (Band) (VHF) 108.00-111.95MHz using even decimals,
112.00-117.95MHz using all
• Emissions A9W
• Range VHF formula - 12√F(flight level), or accurately 1.25 √H1=1.25 √h2
• DOC (Designated Operational Coverage)
• Range factors Transmission power, station elevation, aircraft altitude
• Accuracy ±5º on 95% of occasions
• Accuracy factors Beacon alignment, site error, propagation error,
airborne equipment error, pilotage
• Failure warning : Warning flag appears if:
Low signal strength
Airborne equipment failure
Ground equipment failure
Indicator failure
Low or no power
Tuning in progress
• Test VOR VOT – Preflight check, 000º from or 180º TO, ±4º

VOR
USES
• MARKING BEGINNING/END OF
AIRWAYS
• FOR TERMINAL LET-DOWN
PROCEDURES
• AS HOLDING POINT / MARK
HOLDING PATTERNS
• FOR ENROUTE POSITION LINES

VOR
• BEARING BY PHASE COMPARISON
• VOR TX Transmits two SIGNALS
a) A 30 Hz FM Omni-directional REFERENCE
SIGNAL PRODUCES A CONSTANT PHASE ,
IRRESPECTIVE OF THE Rx BRG FM VOR Tx
b) A 30 Hz AM VARIABLE PHASE (Directional)
SIGNAL created by a rotating transmission pattern
(LIMACON)
• BOTH a) and b) above are synchronised such that
i) THE TWO ARE IN PHASE WHEN THE A/C VOR
Rx IS DUE MAGNETIC NORTH OF THE VOR Tx
ii) THE PHASE DIFFERENCE MEASURED AT ANY
POINT WILL EQUATE TO THE AIRCRAFT’S
MAGNETIC BEARING FROM THE VOR

000
030
330
060
090
300
120
180
270
150
240
210
VOR
Radials
VOR
(QDR)
MAG NORTH

VOR : FREQUENCIES
• OPERATE IN VHF BAND( 30 to 300 MHz )
• ALOTTED Freq : 108 To 117.95 MHz
• a) 40 CHANNELS - 108 – 112 MHz PRIMARILY
ILS BAND Short Range & Terminal VORs ( Even
Decimal Digits for VOR) i.e. 108.0, 108.05, 108.2,
108.25, 108.4 etc (ODD Decimal Digits ARE USED
BY ILS) b) 120 CHANNELS 112 to 117.95
• EMISSION CODE: A 9 W
• A- Main carrier is amplitude modulated
• 9 – Composite System
• w - COMBINATION OF TELEMETERY, T-PHONY &
T-GRAPHY

VOR
(Very High Freq Omni Range )
• Principle Of Operation: BRG BY PHASE
COMPARISON
• Frequency Band: 108 – 117.95 MHz
108- 112 SHARED WITH ILS-VOR EVEN
DECIMAL(108.20, 108.25….) AND ILS ODD
DECIMAL (108.10, 108.15……)
• Range – Line of Sight Range Calculation
• Uses: Navigation(Position Line), HOMING,
TRACKING OUT,
• Advantages
• Accuracy And Reliability
• D VOR

Period 93&94
PRESENTATION AND INTERPRETATION/
APPLICATION OF
• RADIO MAGNETIC INDICATOR (RMI)
• HORIZONTAL SITUATION INDICATOR (HSI)

Relat
000
030
330
060
090
300
120
180
270
150
240
210

OBSSELECTION
FROM
TO
000
030
330
060
090
300
120
180
270
150
240
210

OBS
SELECTION
FROM
TO
000
030
330
060
090
300
120
180
270
150
240
210

Phase QDR QDM HDG Rel OBS To/ L/R
Diff (M) Brg From Dots
A = B±180=C = D + E F±90=
050 010 240
035 005 To Fly left 2
dots
216 040 035
225 050 To Center
020 030 To Full scale
Fly Left
070 075 240
250 240 250
020 020 From Fly left 1
dot

050 050 230 010 220 240 To Fly left 5
dots
035 035 215 210 005 219 To Fly left 2
dots036 036 216 040 176 035 From Fly left 1/2
dots225 225 045 355 050 045 To Center
200 200 020 030 350 030 To Full scale
Fly LrftFly left 5

050 050 230 010 220 240 To Fly left 5
dots
035 035 215 210 005 219 To Fly left 2
dots
036 036 216 040 176 035 From Fly left 1/2
dots
225 225 045 355 050 045 To Center
200 200 020 030 350 030 To Full scale
Fly Lrft
070 070 250 075 175 240 240 Fly left 5
dots
250 250 070 240 190 250 From Center
020 020 200 180 020 018 From Fly left 1
dot

000
030
330
060
090
300
120
180
270
150
240
210
2
1
OBS
075

000
030
330
060
090
300
120
180
270
150
240
210
000
030
330
060
090
300
120
180
270
150
240
210

OBS
COURSE DEVIATION INDICATOR (CDI)
VOR
060

• RADIO MAGNETIC INDICATOR (RMI)
HDG(M)
2
Presentation And Interpretation
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HDG(M)
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VOR SUMMARY
• CHARECTARISTICS: MAG BRGs, Day&night
• FREQ : 108 TO 119.75 MHz; 160 Channels
• USES : Airways, Airfield Let Downs, Holding
Pts , En-route Navigation
• PRINCIPLE OF OP: Brg by Phase Comp OF
TWO 30 Hz SIGNALS
• IDENTIFICATION: 3 Letter aural Morse or
Voice every 10 sec, Cont TONE for VOT
Also ATIS using AM on Voice
• MONITORING: Auto Site Monitor +/- 1 Deg
Ident Suppressed at St By Initial Sw On

• TYPES: CVOR - Ref Sig FM, Var Sig AM
• Limacone Polar Diagram Rot.
Clockwise
• DVOR – More Accurate, less site
error
• Ref Sig AM, VarSig FM, rot anti-clock.
• TVOR: Low Power Tx at Airfields
• VOT : TEST VOR giving 180 Radial
• a/c Eqpt should give < ± 4 Deg error
• OPERATIONAL RANGE: Tx Power. LoS.DOC
• ACCURACY :Affected by, Site Error, Scalloping
• Airborne Eqpt Error +/- 3 Deg
• CONE of CONFUSION: OFF Flag may appear

HSI (Horizontal Situation Indicator)
• Presentation
• Modes of Operation
• Interpretation and Apllication

MODES
• Modes of Operation
OFF
HDG
VOR/NAV
GS
GS AUTO
ALT
APPR
APPR II
GA
IAS
VS
MACH

Period 95&96
INSTRUMENT LANDING SYSTEM (ILS)
COMPONENTS – GROUND INSTALLATION
COVERAGE AND RANGE
GLIDE PATH ANGLE, FALSE GLIDE PATH
FREQUENCIES: LOCALISER & GLIDE PATH PAIRING
TUNING & IDENTIFICATION
RECEIVER & CONTROLS
DATA PRESENTATION
AIRCRAFT HANDLINGWITH REFERENCE TO ILS
INDICATIONS
PERFORMANCE CATEGORIES

ILS
( Instrument Landing System)
• Components – Ground Installation
• Coverage and Range
• Glide path Angle, False Glide path
• Frequencies: Localiser & Glide path Pairing
• Tuning & Identification
• Receiver & Controls

ILS - PRINCIPLE
• ILS IS A PRECESSION APPROACH AID
BASED ON BEARING BY LOBE
COMPARISON
• IT PROVIDES GUIDANCE TO THE PILOT
BOTH IN THE HORIZONTAL PLANE
(DEVIATION FROM EXTENDED RUNWAY
CENTER LINE) AND THE VERTICAL PLANE
(DEVIATION FROM THE GLIDE PATH)
• IT PROVIDES VISUAL INSTRUCTIONS TO
THE PILOT RIGHT DOWN TO DH/DA.

ILS - COMPONENTS
GROUND INSTALLATION
• LOCALISER
• GLIDE PATH
• MARKER BEACONS
• BACK COURSE APPROACHES
• LOCATOR BEACONS
• DME
ILS FREQUENCIES
• LOCALISER –108 –111.975( ODD 1st
decimal)
• GLIDE PATH - 329.15 –335 MHz(Paired with
L)

LOCALISER LOBES &
THEIR COVERAGES
150 Hz
90 Hz
LOCALISER Tx
Coverage
Within +/- 10 deg ------25 NM
Within 10 – 35 deg -------17 NM
Outside 35 deg ------------10 NM
20 Deg
25 NM
17 NM
35 Deg
BEYOND 35 Deg
10 NM

Lclzr MHz G’Path
108.10 334.70
108.15 334.55
108.3 334.10
108.35 333.95
108.5 329.90
108.55 329.75
108.7 330.50
108.75 330.35
108.9 329.30
108.95 329.15
109.1 331.40
109.15 331.25
109.3 332.00
109.35 331.85
109.50 332.60
109.55 332.45
109.70 333.20
109.75 333.05
109.90 333.80
109.95 333.65
110.1 334.40
110.15 334.25
110.3 335.00
110.35 334.85
110.5 329.60
110.55 329.45
110.70 330.20
110.75 330.05
110.90 330.80
110.95 330.65
111.10 331.70
111.15 331.55
111.30 332.30
111.35 332.15
111.50 332.9
111.55 332.75
111.70 333.5
111.75 333.35
111.90 331.1
111.95 330.95
Frequency Pairs Allocated For ILS

90 Hz
150 Hz
GLIDE PATH – LOBES &
THEIR COVERAGES
LINE ALONG
WHICH EQUAL
90 Hz AND 150Hz
SIGNAL IS RECEIVED
OR DDM IS ZERO
27
GP Tx
UPTO 10 NM
WITHIN 8 DEG IN AZIMUTH EITHER SIDE
VERTICAL PLANE COVERAGE
FROM 0.45 θ TO 1.75 θ
ABOVE THE HORIZONTAL PLANE
WHERE θ IS THE GLIDE
SLOPE ANGLE

ILS
• Data Presentation – Display System
• Data Interpretation
• Aircraft Handling With Reference To ILS
Indications
• Performance Categories

Period 97&98
VHF MARKERS
• PURPOSE
• FREQUENCY AND RADIATION PATTERNS
• RANGE
• COCKPIT INDICATIONS
• LOW / HIGH SENSITIVITY SELECTION
RADIO ALTIMETERS
• FREQUENCY MODULATION & ITS APPLICATION TO
HEIGHT MEASUREMENT
• USES
• ADVANTAGES AND
• LIMITATIONS

VHF MARKERS
• Purpose
• Frequency and Radiation Patterns
• Range
• Cockpit Indications
• Low / High Sensitivity Selection

• Marker Passage Indications Marker Code Light
• OM - - - BLUE
• MM • - • - AMBER
• IM • • • • WHITE
• BC • • • • WHITE

RADIO ALTIMETERS
• Frequency Modulation & Its Application to
Height Measurement
• Uses
• Advantages and
• Limitations

RADIO ALTIMETER INDICATOR
WARNING FLAG
DECISION
HEIGHT
INDICATOR
DECISION HEIGHT
SETTING KNOB
TEST

Period 99&100
RADAR
• PRINCIPLE
MEASUREMENT OF RANGE
MEASUREMENT OF BEARING
• RADAR PARAMETERS
FREQUENCY RANGES
PULSE WIDTH
PRF

RADAR
• Principle
Measurement of Range
Measurement of Bearing
Radar Parameters
Frequency Ranges
Pulse Width
PRF

RADAR – RAdio Detection And Ranging
• Developed before WW – II
• USED on Ground and in Air
• Initially Only PULSE Radars Later CW
• Today Extensively used by Civil/ Mil/ Wx etc
• PRINCIPLE
• EM Energy Transmitted in Short Pulses : They get
Reflected by Target A/C . Reflected pulses Picked
up by the Rx at the Tx Locn. Time taken for the
energy to travel to and fro depends on the
distance. The direction in which the antenna is
pointing at the time of the Reception gives the
direction of the Target Aircraft.

• TYPES OF RADAR
• PRIMARY RADAR-
TRANSMIT ENERGY( EM WAVES) IN PULSES
ENERGY REFLECTED BY OBJECTS IN THEIR PATH
THIS IS PICKED UP BY THE Rx AND
DISPLAYED GIVING DIRECTION AND RANGE (DIST)

• SECONDARY RADAR
• A SECONDARY RADAR TRANSMITS
ON ONE FREQ BUT RECEIVES OS A
DIFFERENT FREQ.
• SYSTEM USES AN INTERROGATOR
AND A TRANSPONDER.
• TRANSPONDER MAY BE ON THE
GROUND OR IN THE AIRCRAFT

PULSE
WIDTH
PULSE RECURRENCE
INTERVAL
OR
PULSE RECURRENCE
PERIOD
1 2
PULSE
WIDTH
+
0
-
+
0
-
TIME

• First Symbol
• This tells the type of modulation on the main carrier wave. This
includes:
• N No modulation.
• A Amplitude modulated, double sideband.
• H Amplitude modulated, single sideband and carrier wave.
• J Amplitude modulated, single sideband, suppressed carrier
wave.
• F Frequency modulated.
• G Phase modulated.
• P Pulse modulated, constant amplitude.
• K Pulse modulated, amplitude modulated.

• Second Symbol
• This designates the nature of the signal or signals modulating the
main carrier:
• 0 No modulating symbol.
• 1 Single channel containing quantised or digital information
without the use of a modulating sub-carrier.
• 2 Single channel containing quantised or digital information,
using a modulating sub-carrier.
• 3 Single channel containing analogue information.
• Two or more channels containing quantised or digital
information.
• Two or more channels containing analogue information.
• Composite system comprising 1, 2 or 7 above, with 3 or 8 above.
• X Cases not otherwise covered.

• Third Symbol
• Type of information transmitted. (This does not include
information carried by the presence of the waves.)
• N No information transmitted.
• A Telegraphy - for aural reception.
• B Telegraphy - for automatic reception.
• C Facsimile.
• D Data transmission, telemetry, telecommand.
• E Telephony (including sound broadcasting).
• F Television (video).
• W Combination of the above.
• X Cases not otherwise covered.

• Ground Waves
The term ‘ground wave’ is used to describe
all types of propagation except sky waves.
Thus, a surface wave is also a ground
wave, so is a space wave.
• Direct wave and }
+ }
Ground reflected wave } = Space wave }
+ }
and Surface wave } = Ground wave

Period 101&102
DME
( DISTANCE MEASURING EQUIPMENT)
• USES
• RANGE
• ACCURACY AND
• LIMITATIONS

DME - PRINCIPLE
• DME IS A SECONDARY RADAR SYSTEM
WHICH PROVIDES THE RANGE FROM
THE GROUND STATION USING THE
PULSE TECHNQUE.
• IN CONJUNCTION WITH A CO-LOCATED
VOR IT GIVES A RHO-THETA ( RANGE
AND BEARING ) FIX
• MILITARY EQUIVALENT IS THE TACAN
(VORTAC – VOR AND TACAN CO-
LOCATED BEACON )

DME - CHANNELS
• SECONDARY RADAR – FREQ
BETWEEN 962 MHz TO 1213 MHz (UHF)
• DIFFERENCE OF ± 63 MHz BETWEEN
Tx AND Rx FREQUENCY
• CHANNELS NUMBERED 1 TO 126 X
AND 1 TO 126 Y (MIL AIRCRAFT USE
CHANNELS AND CIVIL AIRCRAFT
TUNE VOR/ DME PAIRED FREQUENCY)
• WHEN PAIRED WITH ILS LOCALISER,
IT GIVES PILOT DISTANCE TO GO TO
RUNWAY THRESHOLD

DME - USES
• PROVIDES ACCURATE SLANT RANGE – SO
A CIRCULAR POSITION LINE
• CAN GIVE G/S AND ELAPSED TIME WHEN
SUITABLE COMPUTER SYSTEM IS FITTED
• ACCURATE HOLDING PATTERNS & DME
ARCS CAN BE FLOWN
• RANGE AND HT CHECKS (NON PREC APP)
• ACCURATE RANGES TO THRESHOLD
(MARKER BEACONS CAN BE DISPENSED)
• EXACT RANGE ENABLES IMM RADR IDENT

• BETTER SEPARATION POSSIBLE IN
NON-RADAR AIR SPACE
• VOR/DME FIXES PROVIDE BASIS FOR
SIMPLEST FORM OF R-NAV (AREA NAV)
• PROVIDES ACCURATE RANGE INPUTS
TO MORE ACCURATE AND ADVANCED
R-NAV SYSTEMS (DME/DME FIXES )

BASIC WORKING – RANGE DETERMINATION
• RANGE BY PULSE TECHNIQUE (SLANT
RANGE)
• AIRCRAFT INTERROGATOR TRANSMITS
STREAM OF OMNI DIRECTIONAL PULSES,
SIMULTANEOUSLY RECEIVER STARTS A
RANGE SEARCH
• GROUND BEACON (TRANSPONDER) RE-
TRANSMITS THE RECD PULSES AFTER DELAY
OF 50 MICRO SEC AT A FREQ ±63 MHz OF
RECD FREQ
• AIRBORNE EQPT IDENTIFIES OWN UNIQUE
STREAM OF PULSESAND MEASURES THE
TIME INTERVAL , ELECTRONICALLY &
DISPLAYS IT AS RANGE ACCURATELY
(±0.2NM)

• THEORETICALLY UPTO 100 AIRCRAFT
CAN USE ONE DME TRANSPONDER,
SO AIRCRAFT RECEIVES OWN
RESPONSE PULSES AS WELL AS
OTHER AIRCRAFT RESPONSE
PULSES
• INTERROGATION PULSES 3.5 MICRO
SEC TRANSMITTED IN PAIRSWITH
INTERVAL 12 M/SEC FOR X
CHANNELS AND 36 M/SEC FOR Y
CHANNELS
• TO AVOID AMBIGUITY, EACH AC
TRANSMITS ITS PAIRED PULSES AT
RANDOM INTERVALS ( JITTERING )

• AT TRANSMISSION TIME, RECEIVER SETS UP GATES TO
MATCH THE RANDOM PRF OF TRANSMITTED TWIN
PULSES
• THE RESPONSE INCLUDES
THOSE FM OWN AC PAIRED PULSES &
THOSE FM OTHER AC P/ PULSES
• THE RECEIVING EQPT IS DESIGNED TO RECEIVE
RESPONSES WHICH MATCHITS OWN RANDOMISED PRF.
WHEN THIS HAPPENS, A LOCK-ON IS ACHIEVED AND
DME ENTERS TRACKING MODE
• AS AC RANGE INC/DEC THE GATES SHIFT TO
ACCOMMODATE THE CORRESPONDING INC/DEC. THIS
LOCK AND FOLLOW ENSURESRETURNING TWIN PULSES
ARE CONTINUOUSLY TRACKED
• RANGE IS DISPLAYED BASED ON OFFSET BETWEEN TX
& RX PULSE PAIRS

DME – TWIN PULSES
• THE USE OF TWIN PULSES ENSURES
THAT THE RECEIVER NEVER
ACCEPTS PULSES WHICH MAY BE
MATCHING BUT WHICH ARE SINGLE ,
FOR EXAMPLE THOSE IN RESPONSE
TO OTHER AIRCRAFT RADARS OR
OTHER RANDOM TRANSMISSIONS

DME – RANGE SEARCH
• TO ACHIEVE A LOCK-ON, DME
INTERROGATOR TRANSMITS 150 PULSE
PAIRS PER SEC FOR 100 SEC.
• IF NO LOCK-ON IN 100 SEC, IT REDUCES TO
60 PP/SEC
• ONCE LOCK-ON ACHIEVED, IT REDUCES TO
25 PP/SEC
• DURING RANGE SEARCH COUNTERS/
POINTER ROTATE RAPIDLY FROM 0 TO MAX
RANGE (4 TO 5 SEC IN MOD DME & 25 TO 30
IN OLDER SYSTEMS)
• IF NO LOCK-ON, DROPS TO 0 AND STARTS
AGAIN

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