Pilot Performance - Rods, Cones,
and Visual Flying Rules
by Henry K.
Situational Awareness is ... a continuous
assessment and accurate interpretation of reality
Visual Flying Rules
Two aircraft flying at 150 knots on a head on collision course will travel
one quarter of a mile toward each other in three seconds. It has been estimated
that from the earliest detection of the oncoming aircraft, the point at which
it is barely discernible, there is a maximum avoidance window of 8 seconds.
A more likely point of recognition is at the 4 second time frame. Obviously
in flying under visual flying rules as with smaller, general aviation aircraft,
the safety of flight depends on the ability to see and to avoid other aircraft
and obstacles. The visual component is a key element of maintaining situational
awareness for maximum effectiveness.
Rods and Cones
Rods and cones are the two types of photoreceptors found in the human eye.
Rods are found in the periphery of the retina, while cones are concentrated
centrally and more densely packed. Cones provide the focus on fine detail
and distinguish colour and require relatively high levels of illumination.
Cones provide our straight ahead focused line of sight with the degree of
perception and accuracy influenced by the level of available light. Rods on
the other hand are much more sensitive to light providing a superior capability
to detect movement in low levels of illumination but not distinguishing colours.
Rods provide our peripheral vision that is our visual capability to detect
Visual scanning techniques are designed to employ the movement detection capabilities
of the rods, and the clear, sharply focused ability of the cones, while recognizing
the limitations of the time needed to adjust and refocus while switching from
one view to another. The most effective scanning patterns are based on how
your eyes function, and incorporate a series of short, regularly spaced eye
movements bringing successive areas of the environment into your field of
vision. Successive scans should move 10 degrees and focus on that segment
for at least one second. The most effective scan pattern covers the entire
field of vision in successive movements and focusing of this nature. This
environmental scanning technique is a continuous and ongoing activity for
the early detection of aircraft and weather phenomena, and a general high
level of flight awareness.
It is a continuous process of accurately recognizing what is happening
and adjusting actual performance to desired performance for each task
The strategies, research, processes and methods developed in the field of
aviation provide a framework for effectiveness within the very turbulent and
rapidly changing environment we face today. The series on Pilot Performance
deals with flawless execution within an ever changing environment, and is
based on individual competence, mastery, and a very positive and courageous
spirit of adventure.
Pilot Performance TM
- Superior Performance and Adventure
life youíre either a passenger or pilot ... Itís your choice."
Henry K. is a private pilot, author,
artist, actor, whale watcher, fly fisherman, tour guide, seasonal server and
surfer residing in Tofino, B.C. Canada, as well as a contributing editor
to The CEO Refresher.
like this in Pilot Performance in The CEO Refresher