PILOT NAVIGATION
Senior/Master Air Cadet
Learning Outcomes
Know the basic features of air navigation and
navigational aids
Understand the techniques of flight planning
Understand the affects of weather on aviation
Flight Planning
Introduction
We discussed the triangle of
velocities and looked briefly
We shall
revise
components
at how
the the
triangle
is solvedof the
triangle and learn how this helps us to
plan a flight and then notify other
That is
how we
calculate
some of the
people
of our
intentions.
unknown components of the triangle
from those that we know
Triangle of Velocities
One side
represents
Comprises
of 3movement
vectors of the
aircrafta in
still air
( a vector being
component
of the
triangle having both direction & speed )
drawn wind
to scale
Another represents
speed & direction
The third shows the actual movement of
the plane over the surface of the earth
As a result of the other 2 vectors
Triangle of Velocities
Thus there are 6 components
Wind Speed
Aircraft Heading
Track
Wind Direction
True Airspeed
Groundspeed
Solution of the Triangle
Mental
arithmetic
Micro
computers
As Dalton
long
as
we
have
4 graph
of thecomputer
components
Scale drawing
dead reckoning
on
paper
it can be solved by a number of methods:
Flight Planning
Both in private aviation & military training
flight planning is carried out using a
Pilot Nav Log Card
On this card the flight is divided
into a number of legs
LEG
1
To
Heading
Height
FL
IAS
Mach
Time
ETA
F Remaining
U
E Required
L
Safety Altitude
TAS
Track
Distance
W/V
Temp
G/S
Varn
2
3
4
5
Flight Planning
The card is divided into a number of legs
Before the flight the
Triangle Of Velocities
is solved for each leg
Flight Planning
However
moretoto
be done
before
First, thethere
pilot is
needs
know
the tracks
the goalofisthe
reached
and distances
various legs
So he draws them on a route chart
We will now look at a flight of a bulldog
from Leeming to Marham via Cottesmore
departing from Leeming at 1000 hrs
Flight Planning
TheThe
wind
Wind
forecast
Forecast
is southerly
Is Southfor
Westerly
the first leg
For The Second Leg
Looking at the map the wind lines are
Producing
Crosswind
Forshould
Leg 2 be
drawn
on & youA can
see there
(Hdg &
ByTAS
Drift)
a headwind
forTrack
leg 1Differ
(GS <
)
Flight Planning - Log Entries
TRACK
The Pilot Must Enter Various Details On The
Log Card
Before With
Applying
The Triangle Of
Measured
A Protractor
Velocities:
DISTANCE
Measured From The Chart
Flight Planning - Log Entries
Forecast
ForecastAir
V/W
Temperature
Indicated
Air Leg
Speed
Height The
To Be Flown
Decided
Operational,
SafetyCruising
& Other Speed
Needs
NormallyBy
The
Recommending
Flight Planning - Log Entries
TRUE AIRSPEED
Calculated from the IAS/RAS &
Air
Temperature
Found
from the
Peripheral Information
VARIATION
on
the Chart
Flight Planning – Triangle of Velocities
Usually the Pilot Would use the
Rotatable Compass Rose or
Dalton Computer
We Must Use Graph Paper
The Theory is the same but the
Dalton Computer is much quicker
Flight Planning – Triangle of Velocities
Once these are entered The
Triangle of Velocities can be used
to calculate, for each Leg:
The Heading to counter the wind
The Groundspeed
Flight Planning – Triangle of Velocities
We already have 4 of the 6
elements of the triangle (1st leg)
WIND DIRECTION
WIND SPEED
TRACK
TAS
180º
30 KT
161º
125 KT
Flight Planning – Triangle of Velocities
We First Draw The W/V From The
Direction 180º & Give It A Length Of 3
Units ( To Represent 30 Kt)
W/V
NORTH (TRUE)
Flight Planning – Triangle of Velocities
Next, at the downwind end of the W/V
draw the Trk/GS line in direction 161º
It is an unknown length
This length, the
Groundspeed, is
one element we will
discover
Flight Planning – Triangle of Velocities
All We Currently Know Is That The GS Will
Be Less Than The TAS Of 125 Kt
(We Know This From The Log Card)
So The Max Length Of The Line Will
Be 12.5 Graph Units
Flight Planning – Triangle of Velocities
Next at the other end of the W/V line
draw the HDG/TAS line to A length of
12.5 graph units
(for the speed of 125 kt)
to where it crosses the GS line
& work out the angle with a pair of geometry
compasses
Flight Planning – Triangle of Velocities
Tk/GS
UNKNOWN
LENGHT
HDG/TAS
12.5 Units
ANGLE TO BE
CALCULATED
W/V
3 UNITS
Flight Planning – Triangle of Velocities
We Can Now Calculate That The
Length Of The TRK/GS Line Is 9.6
Units So The GS Will Be 96 Kt
Flight Planning – Triangle of Velocities
Using A Protractor We Find The HDG/TAS Is
166º.
We Can Now Apply The Magnetic
Variation Of 7º To 166º(t) To Give A
Heading Of 173º (M)
Flight Planning – Triangle of Velocities
Entering These On The Log Card We Can
Work Out The Leg Time By Using The Gs
Of 96kt & Distance Of 98nm To Give 61¼
Minutes From Leeming To Cottlesmore
We Can Do The Same For The Second
Leg To Marham
Fuel Planning
Fuel Planning
One of the main purposes of calculating
flight times is to ensure sufficient fuel is
available
If this happens in a car it is inconvenient, in
an aircraft it can be fatal
Fuel Planning
The bulldog consumes fuel at:
12 gallons an hour
So 12.3 gallons are needed for the first leg
12/60 X 61.25 = 12.25
distance
Other Information
The most important is the Safety Altitude
This is the height a pilot must climb to, or
not fly below, in
Instrument Meteorological Conditions
(IMC)
Other Information
This ensures the aircraft does not hit the
ground or obstacles such as TV masts
Other Information
Safety Altitude is calculated by adding 1000’
to the highest elevation on or near the track
& rounding it up to the next 100’
In mountainous regions a greater safety
height is added
Other Information
An aircraft can not descend below the
safety height unless the crew has good
visual contact with the ground or the
services of ATC
ATC Flight Plan
Aircraft crews must notify ATC of their
intentions so the overdue action can be
initiated if the aircraft is overdue
ATC Flight Plan
Additionally aircraft entering busy airspace
have to submit a flight plan so their flight can
be coordinated with other aircraft
ATC Flight Plan
ATC has a standard format for this, including:
Aircraft call sign
Aircraft type
Time & place of departure
Speed & altitude
Route
Safety info
ETA
Conclusion
The principles of flight planning are the same
for across country flight in a bulldog or a
Intercontinental flight on a Boeing
Conclusion
• We must measure tracks & distances from
a chart/databases,
• Calculate the effects of the weather
(especially the wind) ,
• Have sufficient fuel,
• & inform ATC along the route
This ensures that if anything goes wrong
help will be available immediately
Position Fixing
?
Introduction
In the pioneering days of aviation aircraft
could not fly unless the crew could see the
ground, as map reading was the only
means of navigating
Introduction
Later aircraft where fitted with sextants & radio
direction finding equipment, but the big strides
occurred during & after the second world war
Introduction
It was not until the 1970’s that world wide
coverage with a navigation aid known as
Omega was achieved
Introduction
More recently Satellite Navigation (SatNav)
& the Global Position Satellite have come
into use
Introduction
Any process of finding an aircraft’s
position is known as
Fixing
Visual Fixing
There are many factors affecting map reading
At this moment we need to know that when
you look out of an aircraft & identify some
unique feature this gives a visual fix know as
a pinpoint
Visual Fixing
The accuracy depends on the
uniqueness of the feature, accuracy of
the map, & skill of the observer
It is still a reliable method & is
used in the early training of
crews
Radio Aids
If you move a radio through 360º in the
horizontal plane you should find 2 points
where reception is good & 2 points where it is
bad
Radio Aids
The radio direction finder (RDF) works on
this principle. It shows , on a dial in the aircraft,
its bearing from a transmitting beacon.
As long as the position of the Tx beacon is
known a “position line” can be drawn, with
the aircraft being somewhere along this line
Radio Aids
If 2 further position lines can be plotted, with 2
other known beacons, preferably at 60º to
one another, then a “3 position line fix” can
be obtained
Radio Aids
Radio Aids
This was a main method in the 1920s & 1930s.
However it does depend on the range of the
beacon
VOR/DME & TACAN
A more modern method of gathering
position lines is from VOR/DME &
TACAN beacons
VOR/DME & TACAN
TACAN is a military system, & gives the
magnetic bearing, or radial, from the
beacon to the aircraft and the slant range
VOR/DME & TACAN
LYE Ch 35
(109.8)
Bearing - 280º
Slant - 55 nm
The above airfield has a TACAN on
channel 35 & transmits its ID code in
Morse - l y e
VOR/DME & TACAN
VOR/DME is a civilian system
It gives the magnetic bearing, or radial,
from the beacon to the aircraft and the slant
range although the information is less
accurate
Civil aircraft fly from beacon to beacon
VOR/DME & TACAN
There is a beacon at Stappleford airfield
operating on 115.6mhz
On CHANNEL 103
CALLSIGN:
Lima Alpha Mike
LAM
FOR LAMBOURNE
Astro Navigation
Radio beacons are ideal for overland flights,
but for overseas flight early aircrew used
the stars
The principle behind this is that if you think
you know your position (dead or deduced
reckoning) you can calculate the relative
position of the star
Astro Navigation
Using a sextant to measure the angle
accurately you can compare the actual
position of the star to its calculated position
The difference between the 2 represents the
error in the DR position. As with RDF 2 or 3
fixes are needed
Astro Navigation
This can be extremely accurate, but is being
replaced with GPS
However it cannot be jammed by an enemy!
Radar Navigation
Radar Navigation
Radar was invented in the 1930’s &
rapidly developed
Early systems where crude & unreliable
Modern systems , such as used in tornado
are highly effective
Radar Navigation
This enables the radar picture to be matched
to a very accurate map by the press of a
button
This enables the navigator to concentrate on
other tasks, such as weapon system
management
Radar Navigation
The main problems is that the radar
transmits electronic emissions which are
detectable, & radar failure
Radar Navigation
With the rapid development of electronics in
the 1950’s & 60’s area navigation systems
where introduced :
GEE
DECCA
LORAN
& OMEGA
Radar Navigation
These work by measuring the time it takes for
2 synchronized signals to arrive from 2
different stations.
Each pair gives a position line
Radar Navigation
With the advent of global position satellites
fix’s will be available at the touch of a button
with accuracies of a few metres
Active/Passive Systems
We have already seen that the main
disadvantage of radar navigation is their
liability to disclosed there presence &
location to the enemy
This had lead to the development of
Radar Homing Missiles
Active/Passive Systems
Scientists have developed electronic
warfare to enable the use of radar. This
includes frequency hoping “smart” radars. It
is a ever evolving area
EW measures are used to protect “active”
navigation systems, but another approach is
to use equipment that do not transmit, but
merely receive
Active/Passive Systems
This includes GPS information combined with
Internal Navigation Systems.
These are known as Passive Systems