Department of the Air Force and the Navy. AFM 51-40. Air Navigation. Flying Training

453 Pages·24 MB·English

DOCUMENT RESUME
ED 082 051
CE 000 350
TITLE
Air Navigation. Flying Training. AFM 51-40. NAVAIR
00-80V-49.
INSTITUTION
Air Training Command, Randolph AFB, Tex-
SPONS AGENCY
Department of the Air Force, Washington, D.C.;
Department of the Navy, Washington, D.C.
REPORT NO
NAVAIR-00-80V-49
PUB DATE
1 Jul 73
NOTE
452p.
AVAILABLE FROM
Superintendent of Documents, U.S. Government Printing
Office, Washington, D.C. 20402 ($4.50)
MF-$0.65 HC-$16.45
EDRS PRICE.
DESCRIPTORS
Astronomy; Aviation.Technology; *Equipment; *Flight.
Training; Instrumentation; Job Training; *Manuals;
Military Personnel; *Navigation; *Techniques
IDENTIFIERS *Air Navigation
ABSTRACT
This manual provides information on all phases of air
navigation for navigators and student navigators in training. It
develops the art of navigation from the simplest concepts to the most
advanced procedures and, techniques. The text contains explanations on
'how to measure, map, and chart the earth; how to use basic
instruments to obtain measurements of direction, altitude,
temperature, and speed; and how to solve basic navigation problems by
dead reckoning and map reading. Special techniques used to navigate
by radio, radar, and Loran; by using celestial concepts and
procedures; and in polar areas are covered. There is information on
flight publications, weather services, mission planning, inflight
procedures, and low level navigation. The final chapters cover
automatic navigation systems and aerial delivery. (Extensive
diagrams, illustrations and photographs are included together with
attachments on symbol definitidns and term explanations.)
(Author/KP)
FILMED FROM BEST AVAILABLE COPY
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EDUCATION POSITION
DEPARTMENTS OF THE AIR FORCE
AF MANUAL 51-40
AND THE NAVY
NAVAIR 00-80V-49
Washington DC 20330
1 July 1973
Flying Training
AIR NAVIGATION
.
.
This manual provides information on all phases of air *navigation for navigators and student navigators
in training. It develops the an of navigation front the simplest concepts to the most advanced proce-
dures and techniques. The text contains explanations on how to measure, map, and chart the earth;
how to use basic instruments to obtain measurements of direction, altitude, temperature, and speed;
and how to solve basic navigation problems by deed reckoning and map reading. Special techniques
use..",, navigate by radio, radar, and Loran; by using celestial concepts and procedures; and in polar
areas are covered. There is information on flight publications, weather services, mission planning, in-
flight procedures, and low level navigation. The final chanters cover automatic navigation systems and
aerial delivery.
CONTENTS
Chapter
Page
Introduction
1-1
I
Earth and Its Coordinates
2-1.
2
Maps and Charts
3-1
3
Basic Instruments
4
4-1
Dead Reckoning
5-1
5
Lines of Position, Bearings, and Fixes
J.
-6
6-1
.........
Map Reading
i
7
7-1
I
Practical Application of DR and Map Reading
8-1
8
Radio
9
9-1
Radar
10-1
10
''
Celestial Concepts.
11-1
11
Time
12
12-1
Computing Altitude and True Azimuth
13
13-1
Plotting and Interpreting Celestial LOPs
14
14-1
Sextants and Errors of. Observation
15
15-1
Special Celestial Techniques
16
16-1
Celestial Precomputation
17
17-1
Star Identification
18
18-1
I Aug 68, as amended; AFM 51-40, Vol iII, May 59; NAVAIR 00-80V-49, 15 Oct 59, as
Supersedes AFM 51-40, Vol I,
amended; and NAVAIR 00-80V-5I, May 59, as amended. (For summary of revised, deleted or added material, see signature
page.)
OPR: AFDPPTF (Prepared by Hq ATC/DON)
DISTRIBUTION:
F
Air Force:
Navy:
Published by Air Trashing Command in accordance with AFM 5-1, Chapter 13.
For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402
Bookstore
Price: $4.95, domestic postpafcb $4.50, GPO
Chapter..
Page
GriciNavigation
19
19-1
20
Pressure Differential Techniques.
20-1
Loran
21
21-1
22
Flight Information Publications and Air Traffic Control
22-1
Weather Station Services
23
23-1
24
Mission Planning
24-1
Inflight Procedures..
25
Low Level Navigation
26
25 -1
:
Automatic Navigation Systems
27
27-1
Aerial Delivery
28
28-1
A ttaclunent
Symbols:
A1-1
1
.
Abbreviations
2
A2-1
Explanation of Terms
A3-1
3
Index
A4-1
4
-
CHAPTER
1
Introduction
Some form of navigation has been used ever
DEFINING AIR NAVIGATION
since man has ventured from his immediate sur-
The word navigator comes froth two Latin
roundings with a definite destination in mind.
words, navis, meaning ship, and agere, meaning
Exactly how the earliest navigators found their
to direct or move. Navigation is defined as the
matter of con-
way must remain to some extent a
ocess of directing the movement of a craft from
jecture but some of their methods are known. For
one pia= to another. The craft may be in
example, the Phoenicians and Greeks were the
its
broadest sense any object requiring direction or
first td navigate far from land and to sail at night.
Unlike sea or naval
capable of being directed.
They made primitive charts and used a crude form
.
air navigation
movement
navigation,
involves
of dead reckoning. They used observations of the
above the surface. of the earth within or beyor.d
sun and the North Star, or pole star, to determine
the atmosphere. Air navigation, then, can be de-
direction. Early explorers were aided by the in-
fined as "the process of determining the geographi-
vention if the astrolabe (see figure 1-1), but it was
cal position and of maintaining the desired direc-
not until the 1700's that an accurate chronometer
tion of an aircraft relative to the surface of the
(timepiece) and the sextant were invented making
Other terms,
"avigation" and
"aerial
earth."
it possible for navigators to knoW exactly where
navigation" have fallen into disuse in favor of
they were, even when far from land.
the term, "air navigation." Certain unique condi-
Any purposefulmovement in the universe ulti-
mately involves an intention to proceed to a
tions are encountered in air navigation that have a
special impact on the. navigator.
definite point. Navigation is the business of pra
Need for continued motion. A ship or land
ceeding in such a manner as to arrive at that point.
To do this safely is an art.
Navigation is con-
vehicle can stop and resolve any uncertainty of
motion or await more favorable conditions
sidered both an art and a science. Science is in-
if
necessary. Except to a limited extent, most air-
volved in the development of instruments and
methods of navigation as well as in the coniPuta-
craft must Neu going.
Limited eil. ranee. Most aircraft can remain
tions involved. The skillful use of navigational in-
struments and the interpretation of available data
aloft' for only a relatively short time, usually a
may be considered an art. This combination has
matter of hours.
Greater speed. Navigation of high speed air-
led some to refer to navigation as a "scientific
art::
craft requires detailed flight planning and naviga-
tion methods and procedures that can be accom-
As instruments and other navigational aidi have
become_more complicated,,_ an- increasing propor-
plished quickly and accurately.
tion of the developnient has been shifted from the
Effect of weather. Visibility affects the availa-
practicing navigator to the navigational. scientist
bility of, landmarks: The wind has a more direct
who aids in drawing together the applications of
effect upoh the position of aircraft than upon that
principles from such' sciences as astronomy, cartog-
of ships or land vehicles. Changes of atmospheric
raphy, electronics, geodesy, mathematics, mete-
pressure and temperature affect the height meas-
orology, oceanography, and physics. Such applica-
urement of aircraft using barometric altimeters.
1-1
Figure 1-1.
The Ancient Astrolabe
tions aid in explaining navigational phenomena
AIR NAVIGATION PROBLEM
and in developing improvements in speed, ac-
The problem of air navigation is, primarily, to
curacy, or routine actions in practicing the "scien-
determine the direction necessary to accomplish
tific art" of navigation.
the intended flight, to locate positions, and to
The beginning navigator largely practices the
measure distance and time as means to that end.
science of navigation; that is, he gathers data and
When navigation is performed without "aids,"
uses it to solve the navigation problem in a more or
that is, without obtaining or deducing position in-
less mechanical manner. It is not until after many
formation from special equipment specifically de-
hours of flying that the navigator begins to realize
signed to provide only momentary knowledge of
that his total,role involves an integration based ca
judgment. The navigator builds accuracy and re-
position, the basic method of navigation, "dead
liability into his performance by judgment based
reckoning," is 'used.
The military navigator is an
upon experience.
Dead reckoning is the determination of position
indispensable part of many offensive and defeniive
by advancing a previous position, using only direc-
missions. He must be able to plan a mission
tion and speed data. The navigator does this by
covering every eventuality; inflight, he must be able
applying, to the last well-determined position, a
to evaluate the past and current progress of the
vector or a series of consecutive vectors represent-
aircraft and to derive a correct conclusion for the
ing the magnitude and direction of movement that
remainder of the mission. High speed navigation
has been made since the previous position. The
demands that he have the ability to anticipate
changes in flight conditionsto think ahead of
new position obtained is for a specific time and is
the aircraftand to make the correct decision
essentially a predicted or theoretical position. The
immediately on the basis of anticipated changes.
navigator assumes that he can use direction and
1-2
principles and procedures of air navigation used
speed data oreviously determined with reasonable
accuracy to obtain a future position.
by pilots and information on the navigation sys-
tems used by other crew members of multi-place
The most important elements in the plotting of
a dead-reckoning position are elapsed time, direc-
aircraft.
U. S. Air Force, Navigator Refresher Course,
tion, distance, and speed. Knowing these and his
a pro-
AFP 60-1-1, 60-2, and 60-3. This
starting point, a navigator can plot his approximate
is
position, which in turn, can serve as a base for a
grammed text and ground mission primarily used
for navigators requiring annual refresher training.
subsequent course change.
When the function of air navigation is per-
USAF, Air Training Command, The Navigator,
formed with "aids" to navigation, the navigator
USAFRP 50-3, published three times per year by
can provide a new and separate base or starting
ATC. This magazine contains a variety of articles
point from which to use dead reckoning pro-
from world-wide sources that relate to navigation
cedures. When an aid to navigation provides the
and which advance new and different means for
navigator with a position or fix,, any cumulative
accomplishing techniques of navigation.
errors in previous dead-reckoning dements are
The following United States Observatory and
.
cancelled. In effect, the navigator can restart the
U.S. Navy Oceanographic Office publications are
mission, as far as the future is concerned, from
also prescribed for Air Force use:
each new fix or accurate position determined by
Air Almanac
the use of aids.
American Ephemeris and Nautical Almanac
often used with the word,
An adjective
H.O. Pub 9 (Part II), "Useful Tables for the
is
to indicate the type or primary
"navigation,"
American Practical Navigator"
H.O. Pub 211, "Dead Reckoning Altitude and
method being used, such as dead reckoning naviga-
tion, celestial navigation, radar navigation, pres-
Azimuth Tables"
sure pattern navigation, doppler navigation, grid
H.O. Pub 249, "Sight Reduction Tables for Air
navigation, inertial navigation, etc.
Navigation"
The Department of Defense (DOD) Catalog of
Aeronautical Charts and Flight Publications, pub-
SOURCES OF NAVIGATION INFORMATION
lished 'by the Defense Mapping Agency (DMA)
contains information on the basis of issue and
In addition to this manual, several other sources
procedures for requisitioning these publications.
provide complete or partial references to all meth-
The use of the Air Almanac and H.O. 249 Tables
ods and techniques of navigation. Some of these
is discussed in cietail later in this manual.
are:
U. S. Navy Oceanographic Office, Air Naviga-
tion, H.O. Pub 216. Tfililrageneral reference
SUMMARY
book for air navigators.
U. S. Navy Oceanographic Office, American
Some form of navigation has been accomplished
since the ancient Greeks and Phoenicians begin
Practical Navigator, Bowditch, H. 0. Pub 9. An
epitome of navigation, this text provides a com-
sailing far from land. The problems 'of air naviga-
pendium of navigational material. Although de-
tion and the navigator today are far different from
signed primarily for the marine navigator, it has
those experienced by these ancient mariners. With
the advent of newer and higher speed aircraft, the
valuable application for the air navigator:
navigator must be able, to quickly and, accurately
United States Naval Institute, Navigation and.
Piloting, Dutton. This is a teaching text for the
make decisions which directly affect the safety of
the aircraft and the crew. Using proven techniques
elements of marine navigation.
and modern aids, the navigator practices a scien-
Air Training Command, Navigation for Pilots,
ATCM 51-7. This manual explains the basic
tific art.
1-3
CHAPTER
Earth and Its Coordinates
(1) the hour of the day and (2) an elapsed
INTRODUCTION
interval.
Basic to the study of navigation is an under-
The methods of expressing position, direction,
standing of certain terms which could be called the
"distance, and time are covered fullyin,app.opriate
dimensions of navigation. These so-called dimen-
chapters. It is desirable at this time to emphasize
sions of position, direction, distance, and time are
tht! these terms, and others similar to them, repre-
basic references used by the air navigator. A'clear
sent definite quantities or conditions which may
__,understanding of these dimension's as they :relate
be measured in several different ways. For ex-
to navigation is necessary to provide.the navigatoi
ample, the position of an aircraft may be expressed
with a means of expressing and accomplishing the
certain latitude- and
in coordinates such as
. at
These 'terms
practical aspects of air navigation.
longitude. The position, may also be expressed as
being 10 miles southof, a certain city. The study
are defined as follows:
.
Position is a point defined by stated or implied
of navigation demands that the navigatorlea'rn how
coordinates. Though frequently qualified by such
to measure quantifies such as those just defined and
adjectives as "estimated," "dead reckoning," "no
how to apply the units by which they are expressed.
wind," and so' forth, the word "position" always
It is
refers to some place that can be identified.
EARTH'S SIZE AND SHAPE
obvious that a navigator must know his position
before he can direct the aircraft to another position
For most navigational purposes, the earth is
assumed to be a perfect sphere, although in
or in another direction.
Direction is the position of one point in space
Inspection of the earth's crust
reality it
not.
is
relative to another without reference to the dis-
reveals that .there is a height variation of approxi-
tance between them. Direction is not in itself an
mately 12 miles from the top of the tallest moun-
is often measured in terms of its
angle, but it
tain to the bottorn of the deepest point in the ocean.
angular distance from a reference direction.
Smaller variations in the surface (valleys, mOttit:
Distance is the spatial separation between, two
tains, oceans, etc.) cause an irregular appearance.
points and is measured by the length of a line
Measured at the equator, the earth is approxi-
joining them. On a plane surface, this is a simple
L'7fnately 6,887.91 nautical miles in diameter, while
the polar ,diameter is approximately 6,864.57 nau-
problem. However, consider distance on a sphere,
tical miles. The difference in these diameters is
where the separation between points may be ex-
23.34 nautical miles, and this difference may be
preSsed as a variety of curves. It is essential that
It is
used to express the ellipticity of the earth.
the navigator decide exactly "how" the distance
is to be measured. The length of the line, once
sometimes expressed as a ratio between the differ-
the path or direction of the line has been 'deter-
ence and the equatorial diameter:
f.71
mined, can be expressed in various units; e.g.,
22.34
1
Ellipticity =
miles, yards, and so 'forth.
295
6,887.91
Since the equatorial diameter exceeds the polar
Time is defined in many ways, but those defini-
tions used in, navigation consist Mainly of two:
diameter by only 1 part in 295, the earth is very
2.1
nearly spherical. A symmetrical body having the
same dimensions as the earth, but with a smooth
surface; is called an oblate spheroid.
In figure 2-1, Pn, E. Ps, and W represent the
surface of the earth, and Pn-Ps represents the axis
of rotation. The earth rotates from W to E. All
points in the hemisphere Pn, W; Ps approach the
reader, while those in the opposite hemisphere re-
cede from him. The circumference W-E 'is called
the equator, which is defined as that imaginary
the surface of the earth whiz& plane
circle
passes through the center of the earth and is per-
pendicular to the axis of rotation.
Great Circles and Small Circles
A great circle is defined as a circle on the surface
of a sphere whose center and. radius are those of
IRCLE
CSMALL
the sphere itself.
It is the largest circle that can be
drawn on the sphere; it is the intersection with the
surface of the earth of 'any plane passed through
the center.
GREAT
RCLE
The arc of a great circle is the shortest distance
between two points on a sphere, just as a straight
line is the shortest distance between two points on
a plane. On any sphere, an infinitely large number
of great circles may be drawn through any point,
though only one great circle may be drawn through
any two points that are not diametrically opposite.
Several great circles are, shown in figure 2-2.
The largest circle possible whose,
center is also the center °Utile
sphere is called a GREAT CIRCLE.
All other circles ore small chiles.
GREAT CIRCLE
Figure 2-?. A Great Circle
the Largest Circle
Figure 2-1.
the Earth
Schematic Representation
is
of,
in a Sphere
Showing Axis of Rotation and Equator
2-2
ence. A system of coordinates has been developed
Circles on the surface of the sphere other than
great circles may he defined as small circles. A
to locate positions on the earth by means of imagi-
These lines are known as
nary reference lines.
small circle is a circle on the surface of the earth
whose center and/or radius are not that of the
parallels of latitude and meridians of longiv de.
sphere. A special
of small
called'
set
circles,
Once a day, the earth rotates on its
LATITUDE.
latitude, is discussed later.
north-south axis which is terminated by the two
poles. The equator is constructed at the midpoint
In summary, the intersection of a sphere and a
a circlea great circle
plane
the plane
of th:s axis at right angles to it (see figure 2-3). A
is
if
great circle drawn thfough the poles is called a -
passes through the center of the sphere, and a
meridian, and an infinite number of great circles
small circle if it does not.
may be constructed in this manner. Each meridian
Latitude and Longitude
is divided into four quadrants by .the equator and
the poles. Since a circle is arbitrarily divided into
The nature of a sphere is such that any point
360 degrees, each of these quadrants therefore
on it
is exactly like any other point.
There is
contains 90 degrees.
neither beginning nor ending as far as differentia-
Take a point on one of these meridians 30
tion of points is concerned. In order that points
degrees north of the equator. Through this point
may be located on the earth, some points or lines
pass a plane perpendicular to the north-south axis
of reference are inecessary so that other points may
of rotation. This plane will be parallel to the plane
be located with regard to them. Thus the location
of the equator as shown in figure 2 -3 and will
of New York, City with reference to Washington
intersect the earth in a small circle called a parallel
D. C., is stated as a number of miles in a certain
or parallel of latitude. The particular parallel of
direction from Washington. Any point on the
latitude chosen is at 30° N, and every point on
earth can be located in this manner.
this parallel will be at 30°N. In the same way,
Such a system, however, does not lend itself
other parallels can be constructed at any desired
readily to navigation, for it would be difficult to
latitude, such as 10 degrees, 40 degrees, etc.
locate a point precisely in mid-Pacific without any
Bear in mind that the equator is drawn as the
nearby known geographic features to use for refer-
The plane of a Parallel is
The Equator and poles
divide Meridians
parallel to the Equator.
into four equal ports.
The Equator is a great circle
Great circles through the
T'ane is perpendicular
who
poles form Meridians.
to the axis.
Planes of the Earth
Figure 2-3.
2-3