Signal
area
A
signal area need be provided only when it is intended to use visual ground
signals to communicate with aircraft in flight. Such signals may
be needed when the aerodrome does not have an aerodrome control tower or an
aerodrome flight information service unit, or when the aerodrome is used by
aeroplanes not equipped with radio. Visual ground signals may also be useful in
the case of failure of two-way radio communication with aircraft. It should be
recognized, however, that the type of information which may be conveyed by
visual ground signals should normally be available in AIPs or NOTAM. The
potential need for visual ground signals should therefore be evaluated before
deciding to provide a signal area.