Specifications

MIIAYIT)-1472E
5.2.3.3 Fixed-po
inter, mcwin~-scale displays.
5.2.3,3,1 Numerical Procession. Numbers shall progress in magnitude in clockwise direction
around the faces of circular dials (counter-clockwise dial movement for numerical increase). On
venkd or horizontal straight scales, numbers shail increase from bottom to top or from left to right.
5.2.3.3.2 Orientation. Numerals shall be upright when in the reading position.
5.2.3.3.3 A.Iknment of pointer
or fixed reference line, For circular scales, alignment of pointer
or fixed reference line shall be in the 12 o’clock position for rkht-left directional information and in the
9 o’clock position for up-down information. Fo~purely quantitative information, either position may
be used.
5.2.3.3.4 Setting. If the display will be used for setting in a value (e.g., tuning in a desired
wavelength), the unused portion of the dial face shall be covered, and the open window shaIl be large
enough to permit at least one numbered graduation to appear at each side of any setting.
5.2.3.3.5 Tracking. If the display will be used for tnwking, as in the case of a directional
indicator, the whole face of the dial shall be exposed.
5.2.3.3,6 Movirm tape displays. When the scale length nxquimd for acceptable readout accuracy
exceeds the limits of the display package capacity (i.e., compressing the scale marking would make the
display illegible or subject to readout error), moving tape scale format maybe used.
5.2.3.3.7 Corrmo
site scalar/uictorial disdavs. Combinations of scales, pointers and
pictorialized symbols may be used to combine functionally-related information into a single instrument
or display (e.g., tilcial horizon, command heading, truehelative bearing). Significant reference
features (e.g., aircraft or ship symbols, horizon, attitude or pitch scales) shall conform to the general
criteria herein for direction-of-motion, scale-pointer relationships, and legibility.
5.2.4 Cathode raYtube (CRT) dis~lavs. CRT displays shall conform to the provisions below;
however, where a CRT is part of a visual display terminal used for text processing, data entry, or data
inquiry applications in an office environment or equivalent, see 5.16.
5.2.4.1 Si~al size, When a target of complex shape is to be distinguished from a nontarget
shape that is also complex, the target signal should subtend not less than 6 mrad (20 minutes) of visual
angle and should subtend not less than 10 lines of resolution elements. Image quality shall be
consistent with the operator’s needs.
5.2.4.2 Viewing distance. A 400 mm (16 in) viewing distance shall be provided whenever
practicabk. When periods of scope observation will be b or when dim signals must be detected,
the viewing distance may be reduced to 250 mm (10 in). Design should petit the o~er to view
the scope from as close as desired. Displays which must be placed at viewing distances greater than
400 mm ( 16 in) due to other considerations shaIl be appropriately modified in aspects such as dispiay
size, symbol size, brightness ranges, line-pair spacing and resolution.
5.2,4.3 Screen luminance, The ambien[ illuminance shall not contribute more than 25% of
screen brightness through diffuse reflect ion and phosphor excitation. A control shall be provided it)
vtiry the CR-I iummance trom i()%(JImmmwn ambiem hrtinanw 10i’ullCRT kmnnnce. A LWnU()i
shall k prnvitim-i to vat-v the
turninmm svmlmlkiark I-wckgrmmd or dtirk svmbol/ll)minous h~ckgrotlntl
~wntrast rat io. (’ontrast ;d,justment shall not be included m flight deck displays because they are
{li~:tll,lll (’II III FA .4 rrrlll;lfi{m
.