What is F/D on Boeing 777? (Flight Director)

The Flight Director (F/D) is a critical component of the Boeing 777 aircraft’s avionics system. It is an automated guidance system that assists the pilots in flying the airplane accurately and safely. The F/D provides the flight crew with visual cues and commands on the Primary Flight Display (PFD), helping them to maintain the desired flight path, attitude, and speed. In this article, we will delve into the details of the Flight Director system on the Boeing 777, its functionalities, and how it enhances the overall piloting experience.

The Role of Flight Director

The Flight Director system on the Boeing 777 serves as a virtual co-pilot, providing guidance and instructions to the pilots during different phases of flight. It calculates and displays the ideal flight path, taking into account various factors such as climb, descent, cruise, and approach. By doing so, it assists the pilots in maintaining precise control over the aircraft, reducing their workload, and ensuring smooth and efficient operations. Let’s explore the key features and functions of the Flight Director system in more detail:

The Primary Flight Display (PFD)

The Flight Director system primarily operates through the Primary Flight Display (PFD), which is a key instrument panel in the cockpit of the Boeing 777. It provides the pilots with essential flight information, including altitude, airspeed, attitude, heading, and vertical speed. The PFD also displays the Flight Director Bar, which consists of two command bars – the roll (lateral) bar and the pitch (vertical) bar.

The roll bar is linked to the aircraft’s heading and bank angle, while the pitch bar represents the desired pitch attitude and vertical speed. These bars provide the pilots with visual cues and target indications, enabling them to align the aircraft precisely with the intended flight path. The Flight Director system continuously computes and adjusts the positions of these command bars based on the inputs received from other avionics systems, such as the Flight Management Computer (FMC) and the Inertial Reference System (IRS).

When the Flight Director system is engaged, it generates commands on the PFD to guide the pilots in operating the flight controls, such as the control yoke or sidestick, and the throttle levers. These commands are displayed as cues on the PFD, giving the pilots a clear indication of the required control inputs to maintain the desired flight path, attitude, and speed. The Flight Director system takes into account various factors, such as wind, aircraft weight, and configuration, to provide accurate and reliable guidance to the pilots.

Automation and Flight Director Coupling

The Flight Director system on the Boeing 777 is closely integrated with the aircraft’s automation system, allowing for advanced functionality and precise control. The automation system includes features such as Autothrottle, Autopilot, and Flight Management System (FMS), which work in conjunction with the Flight Director to streamline operations and enhance safety.

For example, the Autothrottle system, when engaged, automatically controls the aircraft’s thrust to maintain the desired airspeed as commanded by the Flight Director. This integrated functionality reduces the pilot’s workload and ensures that the aircraft operates within the desired speed envelope.

The Autopilot system, when engaged, allows the aircraft to be flown automatically based on the Flight Director commands. Pilots can select different autopilot modes, such as heading hold, altitude hold, or Flight Level Change (FLCH), which follow the guidance provided by the Flight Director system. This integration of the Flight Director with the autopilot system enables precise and hands-off control of the aircraft, especially during long-haul flights or when operating in adverse weather conditions.

The Flight Director system also works in synergy with the Flight Management System (FMS) on the Boeing 777. The FMS provides the Flight Director with accurate navigation information, flight plan data, and performance calculations. The Flight Director utilizes this information to generate accurate guidance cues for the pilots, ensuring optimal flight paths and fuel efficiency.

Enhancing Piloting Experience

The Flight Director system greatly enhances the overall piloting experience on the Boeing 777 by providing precise guidance and reducing the pilot’s workload. With its advanced automation capabilities and integration with other avionics systems, the Flight Director enables the pilots to focus on higher-level tasks such as aircraft systems monitoring, situational awareness, and decision-making.

Furthermore, the Flight Director system aids in maintaining flight stability and avoiding potential hazards. It helps the pilots achieve a smoother and more controlled flight, minimizing the risk of excessive maneuvers or deviations from the desired flight path. The precise guidance cues provided by the Flight Director allow for smoother transitions during climbs, descents, and turns, enhancing passenger comfort.

Additionally, the Flight Director system contributes to fuel efficiency by optimizing the aircraft’s flight path and power settings. It calculates the most efficient routes, considering factors such as wind patterns and air traffic constraints, ensuring that the aircraft operates with minimal fuel consumption. This efficiency not only reduces operating costs for airlines but also helps to minimize environmental impact through reduced fuel burn and emissions.


The Flight Director (F/D) system is a vital component of the avionics system on the Boeing 777 aircraft. It provides the flight crew with accurate guidance cues and commands through the Primary Flight Display (PFD), ensuring precise control and accurate navigation. The integration of the Flight Director with other avionics systems, such as the Autothrottle, Autopilot, and Flight Management System (FMS), enhances the automation capabilities and safety of the aircraft. With its advanced functionality and automation, the Flight Director system significantly contributes to a smoother, safer, and more efficient flying experience on the Boeing 777.

Sources: Boeing

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