The vertical speed indicator shows the rate of climb or descent.
The airspeed indicator shows the results of power and/or pitch changes in the
The outside visual references used in controlling the airplane include the airplane's nose and
wingtips to show both the airplane's pitch attitude and flight direction with the wings and frame
of the windscreen showing the angle of bank.
"SEE AND AVOID" DOCTRINE
Simply stated, the "See and Avoid" Doctrine is a pilot's best defense against a midair collision.
The "Big Sky, Little Airplane" theory is the key ingredient in the recipe for a midair collision.
The causal factor most often noted in aircraft accident reports involving midair collisions is,
"failure of the pilot to see and avoid the other aircraft." In most cases, at least one of the pilots
involved could have seen the other in time to avoid contact if he had been using his eyes
Statistics taken from the April 1983 AOPA Air Foundation Safety Report reveal some interesting
points concerning midair collisions. Nearly all midair collisions occur during daylight hours, in
good VMC weather conditions. Most midairs occur within five miles of an airport, in the areas
of greatest traffic concentration, and usually on warm, weekend days. Most midairs also involve
maneuvers that are classified as crossing or overtaking. Very rarely were head-on collisions
It was also noteworthy to find that the closing speed (rate at which two aircraft approach each
other) in a crossing or overtaking maneuver is often relatively slow, usually much slower than
the airspeed of either aircraft involved. Again, that is because the majority of midair collisions
are the result of a faster aircraft overtaking and striking a slower one.
The report also revealed some interesting information regarding the vulnerabilities of the human
eye and how its limitations contribute to midair collisions.
The eye, and consequently vision, is vulnerable to just about everything: dust, fatigue, emotion,
germs, fallen eyelashes, age, optical illusions and alcoholic content. In flight, our vision is
affected by atmospheric conditions, windscreen distortion, too much or too little oxygen,
acceleration, glare, heat, lighting and aircraft design. Most importantly, the eye is vulnerable to
the vagaries of the mind. We "see" and identify only what the mind lets us see. For example, a
daydreaming pilot staring into space sees no approaching traffic and is a number one candidate
for a midair collision.
A constant problem source to the pilot (though he is probably never aware of it) is the time
required for "accommodation." Our eyes automatically accommodate for (or focus on) near and
far objects. But the change from something up close, like a dark panel two feet away, to a well-
lighted landmark or an aircraft target a mile or so away, takes one to two seconds or longer for
eye accommodation. That can be a long time when you consider that you need 10 seconds to
avoid a midair collision.
FUNDAMENTAL FLIGHT CONCEPTS