A Primary Flight Display, also known as a PFD, is the pilot’s primary reference for flight information in aircraft equipped with electronic flight instrument systems. A PFC combines the information traditionally displayed on several electromechanical instruments and displays them on a single electronic screen. This not only reduces pilot workload but also enhances situational awareness.
The layout and information displayed on the PFD varies from manufacturer to manufacturer
and installation to installation. Despite this, most Primary Flight Displays are configured with a central attitude indicator and flight director surrounded by other flight parameters. Conventionally, the airspeed tape is placed on the left side of the attitude indicator while the altitude and vertical speed references are on the right. Vertical deviation of ILS glideslope, or VNAV (vertical navigation) is displayed to the right of the AI. Meanwhile, lateral deviation from the ILS, VOR, or FMS track is displayed below the AI. Additionally, a compass reference is provided at the bottom of the instrument while the flight director, approach, autopilot, and auto-throttle modes are located across the top of the instrument.
The first computerized cockpit display was delivered to the Boeing 767 in the early 1980s. The instrument gained immediate popularity and quickly became known as the glass cockpit. Round flight instrument gauges
were replaced with computer-generated graphical representations of the attitude and heading indicator, as well as those for airspeed, vertical speed, turn coordinator, and altimeter. The new instrument display was not only more efficiently organized to present information, but also added color and movement where none had existed before. The central CRT (cathode ray tube, a type of screen similar to an LCD) came to be known as the primary flight display. Additional CRTs were used to show important navigation and weather information on what would later be known as multifunction displays.
Technological advances in aircraft quickly brought PFDs to many aircraft. Today, it is nearly impossible to find a new aircraft without a glass cockpit. More often than not, PFDs are still fed by many of the same data sources as the old round gauges, including pitot tubes and static ports. The key difference is that a PFD uses a computerized signal generator to translate said data into visible images, much like a computer game. A major advantage of primary flight displays is that because they are created with few moving parts, they are highly reliable.
In addition to bright color graphics and precise digital displays, PFDs also began displaying data vertically, making trends easier to track. Navigation data was also incorporated into the PFD, with the localizer needle shown right under the attitude display indicator (ADI). The glideslope ran vertically to the right of the ADI. The turn coordinator was also located at the top of the ADI, making it easier to be included in the pilot’s instrument scan for more precise control.
As major avionics producers like Garmin, Honeywell
, Rockwell Collins
and Avidyne continued to develop their products, they added useful figures such as best angle or best-rate-of-climb speeds. This data would normally have only been kept in the pilot’s memory. Most new attitude indicators now offer pilots graphical guidance to assist with recovery from an upset condition, airborne traffic and even weather information. For primary flight display parts and many more high-quality aviation components, Simplified Purchasing is your source.