AIRPLANE
OPERATIONS
MANUAL
NAVIGATION AND
COMMUNICATION
REVISION 39
2-18-75
Page
1
Code
01
HEAD-UP GUIDANCE SYSTEM (HGS)
The HGS is an electronic and optical system that generates and
displays information in the pilot’s forward field of view. This displayed
information is derived from the airplane’s instruments and sensors.
The system provides information during all flight phases, including low
visibility takeoff, approach and landing in Category IIIa limits. For
additional information on functions and operations, refer to the
manufacturer’s manual.
HGS symbology has been optimized for full flight routine use and
provides speed, altitude, heading, navigation data, wind speed and
direction, flight path and other information to the pilot, in symbolic
format, that is superimposed on the pilot’s view. The HGS also
provides guidance cues for low-visibility takeoff and CAT IIIa approach
and landing operations, reducing delayed takeoffs and/or landing
diversions due to reduced visibility conditions.
The HGS provides the following display functions:
− Primary Flight Display (PFD), which is similar in form and
function to the existing PFD on the airplane’s main panel;
− Category IIIa approach display which provides HGS-calculated
approach and flare guidance;
− Approach display that repeats the airplane Flight Director
guidance during CAT I and CAT II approaches;
− Visual approach display for use during a VFR approach;
− Low-visibility takeoff display, with all the symbology required for
this mode of operation;
− Test display available for Test Mode.
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