The Primary Flight Display (PFD) is an instrument which integrates and depicts, on a single display, all of the information that was historically presented on a number of individual electromechanical instruments. The PFD has evolved from a basic attitude indicator/flight director combination, presented electronically on a CRT, to an Electronic Attitude Direction Indicator (EADI) which, variable by manufacturer, added additional information such as heading, altitude and airspeed.

The modern PFD displays virtually all of the information that the pilot requires to determine basic flight parameters (altitude, attitude, airspeed, rate of climb, heading, etc) plus autopilot and auto-throttle engagement status, flight director modes and approach status. Depending upon the phase of flight and pilot selections, the flight director will provide appropriate lateral guidance to maintain the selected track, heading or approach and missed approach track and vertical guidance for climb and descent, level off, approach and missed approach. This greatly reduces pilot workload while in manual flight and facilitates flight monitoring with the autopilot engaged as all required information is displayed on a single instrument. Skybrary