220.127.116.11 Syntax. Warning, caution, and advisory messages
shall concisely convey the nature of the problem and the specific subsystem
or location. A standard syntax is desirable for all messages, but shall be
subordinate to a clear statement of the problem if not appropriate.
18.104.22.168 Prioritization. Messages should be grouped by
urgency level. Warnings shall be presented at the top of the annunciator
area of the display (which may be at the top or bottom of the display), with
cautions and advisories following in that order. The acquiring activity
shall approve a scheme for ordering alert messages, such as in order of
occurrence, in order of priority, within urgency levels (see 6.3.1).
22.214.171.124 Overflow memory. A system to display messages
stored in overflow memory shall be used when the number of active messages
exceeds the capacity of the display. If there are more messages than there
is space to display them all, an indication shall be provided to the
operator that additional alerts exist. Any overflow messages shall be stored
and a capability shall be provided to recall/scroll through alerts so
stored. If a new alert condition arises:
a. The new message shall be placed with messages of equal
b. If room does not exist on the display, a message of lower
criticality shall be replaced. The replaced message shall be moved into
overflow. If no lower criticality message exists, a message of equal
criticality shall be moved into overflow.
c. Messages placed in overflow shall be grouped with
messages of equal criticality.
126.96.36.199 Color coding. When color is used to provide a
unique and easily distinguishable coding method for all three alerting
categories, red shall be reserved for warning messages, yellow shall be
reserved for caution messages and a third color (green preferred with blue
and white as non-flight deck options) shall be used to represent advisory
level messages. The chromaticity of the third color shall be significantly
different from the chromaticities of the red and yellow signals. All three
selected colors must be different enough from the background color so that
symbols and words are easily readable.
188.8.131.52 Minimum message duration. It is possible for a
warning or caution condition to exist for such a short period of time that a
crew member may not have a chance to identify the condition, even though the
condition has been cured or otherwise ended. Therefore, a minimum message
display time of three seconds is required for all warning and caution