Specifications

?vIIIATD-1472E
conditions to designate
displays which have physical appearance similar to legend switches on the
same panel.
5.2.2.2.4 Lettering. The size and other characteristics of lettering shall conform to 5.5 herein.
5.2.2.2.5 Visibility and legibility. In other than aircrew stations, and with the exception of
warning and caution indicators, the lettering on single-legend indicators shall be visible and legible
whether or not the indicator is energized.
5,2.2.2.6 Multi-function legends. Indicators designed to provide alternately-presented legends
shall present only one legend at a time, i.e., only the legend in use shall be visible. Indicators using
“stacked” legends shall conform to the following:
a. When the rear legend is energized, i[ shall not be obscured by the front legend.
b. Parallax shall be minimized.
c. Front and rear legends shall have approximately equal brightness
d. Front and mar Jegends shall have approximately equal legendbackground contrast.
5.2.2.3 Simple indicator lights.
5.2.2.3.1 ~. Simple indicator lights should be used when design considerations preclude the
use of legend lights.
5.2.2.3.2 Spacing. The spacing between adjacent edges of simple round indicator light fixtures
shall be sufficient to permit unambiguous labeling, signal inteprlation, and convenient buIb removal,
5.2,2.3.3 Coding. Simple indicator Iights shall be coded in conformance with Table II;
however, the different sizes shown are intended onlYfor the attention-~ettituz value that larger lights of
at least equal luminance provide in relation to indim-tor lights of lesser~mpohce.
TABLE IL Coding of simple indicator tights
SXZETYPE
222mnlmo
(3 to 5 see)
>25 mm (1 in)
STEADY
RED
Emergency condi-
tion (impending
personnel or equip-
ment disaster).
Master summation
(system or
subsystem)
kffilflmrlinn:
action stopped;
laliure, slop U(lwl.
COLOR
YELLOW GREEN
WHITE
Extreme caution
(impending
danger)
l%li~~ rht=ck:
recheck.
Master
summation
(system or
subsystem)
(k-)ahead:
in tolerance:
dGCC~tdbk ,
rcad~.
1’1