made only during
the spells when he is flying horizontally.

In this stage of his tuition, the pupil must learn also to make a
vol-plane, or descent with his engine stopped. The essential point to
be borne in mind, here, is that an aeroplane will continue in flight,
and remain under control, even when it is no longer propelled by its
engine. But what the aviator must do, should his engine stop through a
breakdown, or should he himself switch it off, is to bring the force
of gravity to his aid, and maintain the flying speed of his craft by
directing it in a glide towards the ground. Provided he does this, and
keeps his machine at such an inclination that it is moving at a
sufficient speed through the air, he will find that the craft
maintains its stability and that he has full command over its control
surfaces, being able to turn, say, right or left, or either increase
or slightly decrease the steepness of his descent. But all the time,
of course, seeing that it is gravity alone which is giving him his
flying speed, he is obliged to plane downward.

[Illustration: PUPIL AND INSTRUCTOR IN FLIGHT (2). _Photo by Topical
Press Agency._

This shows clearly how the instructor, from his seat behind the pupil,
can lean forward and, by placing his hand on the control lever, check
the novice in an error of manipulation.]

A vital point to remember, when a pupil is handling a "pusher" type of
biplane, is to incline the machine well downward, by a use of the
elevator, before switching off the motor. Unless this is done, and if
the machine is, say, at its normal horizontal angle when the engine is
stopped, the sudden removal of pressure from the tail-planes of the
craft, brought about by the absence of the wind-draught from the
propeller, may cause the tail so to droop as to render inoperative any
subsequent action of the elevator. When the tail droops, the
main-planes are set at a steep angle to the air, and this has a
slowing-up influence on the whole machine. It threatens therefore to
stand still in the air; its controls become useless; and the pupil is
faced probably with the danger of a side-slip.

A story will illustrate this point; and it is one that has a special
significance, seeing that the error which might have cost him his life
was made by an aviator of experience. He had learned to fly on a
monoplane, and had devoted his subsequent flying, for many months, to
this one type of machine. Then he found himse