What is SG on Boeing 777? (Symbol Generator)

The Symbol Generator (SG) is an essential system on the Boeing 777 aircraft that plays a crucial role in displaying information to the flight crew on the Primary Flight Display (PFD) and Navigation Display (ND). It is responsible for generating graphical symbols that provide the pilots with critical flight information, including attitude, altitude, airspeed, and navigation data. The SG ensures that the flight crew has accurate and real-time information at their disposal, facilitating safe and efficient flight operations.

Boeing has incorporated advanced avionics systems in the Boeing 777, and the Symbol Generator is at the heart of these systems. It takes data from various sensors and avionics systems and converts them into meaningful symbols that can be easily interpreted by the pilots. These symbols are then displayed on the PFD and ND, allowing the flight crew to monitor the aircraft’s performance and navigate through different flight phases.

The Symbol Generator is integrated with other avionics systems, such as the Flight Management System (FMS) and the Inertial Navigation System (INS), to provide accurate and reliable flight information. It receives data inputs from these systems and processes them to create the necessary symbols. For example, the SG uses attitude, altitude, and airspeed data from the INS to generate the aircraft’s pitch and roll indicators on the PFD, enabling the pilots to maintain the desired flight attitude.

Another crucial function of the Symbol Generator is providing navigation information to the flight crew. It generates symbols for waypoints, airports, and other navigational aids on the ND, allowing the pilots to navigate along the planned flight route. The SG receives data from the FMS, which includes the flight plan and navigation waypoints, and overlays this information onto the ND, providing a comprehensive and intuitive display of the aircraft’s position relative to the planned route.

The Importance of Symbol Generator in Flight Operations

The Symbol Generator plays a critical role in flight operations and enhances the situational awareness of the flight crew. By generating clear and informative symbols on the PFD and ND, it enables the pilots to quickly assess the aircraft’s status and make informed decisions. Here are a few key reasons why the Symbol Generator is indispensable in the Boeing 777:

1. Enhanced Safety: The Symbol Generator ensures that the flight crew has real-time access to crucial flight parameters, such as airspeed, altitude, and attitude. With accurate and up-to-date information, pilots can effectively monitor the aircraft’s performance and respond to any abnormal situations or emergencies promptly.

2. Improved Efficiency: The SG simplifies the information presented to the flight crew, making it easier to interpret and act upon. By providing graphical symbols instead of raw data, it reduces pilot workload and allows them to focus on critical tasks, such as flight path management and system monitoring.

3. Enhanced Navigation: Navigation is a crucial aspect of flight operations, and the Symbol Generator greatly aids in this regard. By overlaying navigation symbols on the ND, it provides a clear representation of the aircraft’s position, waypoints, and flight path. This improves the pilots’ spatial awareness and helps them navigate accurately and efficiently.

The Evolution of Symbol Generator on Boeing 777

The Symbol Generator system on the Boeing 777 has undergone significant advancements to improve its functionality and performance. Here are a few notable developments in the evolution of the SG:

1. Software Upgrades: Boeing continually updates the software of the Symbol Generator to enhance its capabilities and incorporate new features. These upgrades often introduce improved symbol generation algorithms, enhanced compatibility with other avionics systems, and better integration with the overall aircraft systems.

2. High-Resolution Displays: The introduction of high-resolution displays, such as the Liquid Crystal Display (LCD) technology, has significantly impacted the Symbol Generator’s performance. The SG now produces sharper and more detailed symbols, improving the readability and clarity of the information presented to the pilots.

3. Integration with Advanced Systems: The Symbol Generator has become more tightly integrated with advanced systems, such as the Enhanced Ground Proximity Warning System (EGPWS) and the Traffic Collision Avoidance System (TCAS). This integration allows for the generation of additional symbols related to terrain proximity and traffic awareness, further enhancing the pilots’ situational awareness.

4. Data Connectivity: With the advent of modern connectivity solutions, the Symbol Generator can now receive real-time data updates from ground-based systems. This enables the SG to display dynamic information, such as weather radar images, NOTAMs (Notices to Airmen), and other relevant data, providing the flight crew with the latest information during the flight.

The continuous evolution of the Symbol Generator system ensures that the flight crew benefits from the latest advancements in avionics technology. As new technologies emerge and aircraft systems become more interconnected, the Symbol Generator will continue to play a vital role in facilitating safe, efficient, and informed flight operations on the Boeing 777.


The Symbol Generator (SG) on the Boeing 777 is a sophisticated system that generates graphical symbols for displaying critical flight information to the flight crew. It enhances safety, improves efficiency, and aids in navigation. With its continuous evolution and integration with advanced avionics systems, the Symbol Generator ensures that pilots have real-time and accurate information, enabling them to make informed decisions and safely navigate the aircraft. The Symbol Generator is an indispensable component of the Boeing 777’s advanced avionics suite, contributing to the overall safety and reliability of this iconic aircraft.

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