Two events are involved in every attempt at visual aircraft recognition. First, you must
visually detect the aircraft. Second, you must inspect the aircraft to distinguish the
characteristics of shape that make the aircraft recognizable as a particular aircraft.
Because detection and recognition are basically visual processes, your ability to detect
and recognize an aircraft is heavily dependent upon your visual keenness. The task
requires long-range detection of small objects against a variety of backgrounds, followed
by an inspection of the object to distinguish recognition features. You must have good
(corrected, if necessary) eyesight.
Several physical factors influence your ability to detect and recognize aircraft. These
include size of aircraft and viewing aspect, contrast with background, visibility
conditions, terrain masking, search sector size, and alert warning.
Size of Aircraft and Viewing Aspect
The distance at which you can detect and recognize an aircraft increases with aircraft
size. The size varies with the type of aircraft (large troop transports as opposed to small
observation aircraft) and also as a function of the aspect from which you view the
aircraft. Apparent size of the aircraft is much larger to you at broadside aspects than at
incoming or outgoing aspects. The viewing aspect can also influence you by masking
critical recognition features. For example, you are standing on the ground and your
critical recognition feature is the vertical tail assembly, that feature might be masked by
the wing structure (Figure 2).