Man's physical universe

xanabras

UNIT V

SECTION 9

AVIGATION IS THE SCIENCE OF CONDUCTING AN

AIRCRAFT FROM A POINT OF DEPARTURE TO THE

DESTINATION

Introduction.

The science of directing an aircraft from here to there is much different

from that of traveling over well-marked highways by automobile.

Familiar landmarks do not look the same from an airplane as they do

from the ground. In bad weather and at night even familiar landmarks

are often lost to view.

battle has been won.

When one has once learned to fly, only half the

The next problem is that of learning how to navigate

an aircraft. The navigation of an aircraft is often spoken of as

avigation to distinguish it from the navigation of watercraft.

There are four recognized methods of navigating aircraft: (1) navigation

by celestial observation, (2) navigation by terrestrial observation

(pilotage), (3) navigation by dead reckoning, and (4) navigation

by use of the radio beam.

1. Navigation by Celestial Observation Depends upon the Frequent

Determination of the Position of an Airplane by Observation

of the Sun or Stars.

Navigation by celestial observation is the most advanced and most

scientific of all of the methods, but it can be used only when the sun

or selected stars are visible and thus permit the determination of their

angle of elevation with the sextant. The observations and computations

require more attention than a pilot can spare, so that celestial

navigation is only possible when a navigator can accompany the

pilot.

Celestial navigation is practical either day or night provided one

can fly above the clouds, and efficient operation demands that long

flights be made at high altitudes. Celestial navigation is especially

valuable for flying across oceans where there are no landmarks and

when flying in the substratosphere above an overcast because often

radio signals are affected unfavorably at these altitudes.

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