What is LSK on Airbus A320? (Line Select Key)

The Line Select Key (LSK) is an important feature found in the cockpit of the Airbus A320 aircraft. It is a programmable button that allows pilots to input information quickly and efficiently into the aircraft’s flight management system (FMS).

The Airbus A320, a narrow-body commercial passenger aircraft, has become one of the most popular choices for airlines around the world. Its advanced technology and efficient design make it a reliable and cost-effective option for both short and medium-haul flights. The inclusion of the Line Select Key is just one of the many features that contribute to the A320’s success.

Using the Line Select Key

The Line Select Key is typically located on the aircraft’s control display unit (CDU) panel, which is part of the cockpit’s multifunction control and display unit (MCDU) system. Each CDU has multiple Line Select Keys, with each key having a corresponding label indicating its specific function.

When a pilot wants to input data or make selections on the MCDU, they can use the Line Select Key to expedite the process. The LSK acts as a quick-access button to pre-defined options or inputs that are frequently used during flight operations.

For example, if a pilot needs to select a specific navigation waypoint, the LSK can be used to quickly access the waypoint’s name from a pre-loaded database. Once selected, the name appears on the CDU display, and the pilot can confirm the selection by pressing another key.

Similarly, the Line Select Key can also be used in combination with other buttons to modify flight plans, set performance parameters, and input data related to weight and balance calculations.

Overall, the Line Select Key improves efficiency and reduces the time required for pilots to input essential information into the aircraft’s systems. This not only streamlines flight operations, but it also enhances safety by minimizing distractions and allowing pilots to focus on other critical tasks.

The LSK Design and Labels

The Line Select Key is typically a square-shaped button with a numeric display next to it. The display shows the current status or selected input associated with that specific LSK.

Each Line Select Key is labeled with a combination of letters and numbers to indicate its function. The labels may vary depending on the aircraft operator and the specific configuration of the MCDU system. However, there are some common labels found on most Airbus A320 aircraft:

  • LSK 1L/1R: These keys are often used for aircraft initialization and configuration purposes, such as setting the flight plan, performance calculations, and departure procedures.
  • LSK 2L/2R: These keys are typically used for in-flight modification of the flight plan, navigation waypoint selection, and monitoring of the progress of the flight.
  • LSK 3L/3R: These keys are commonly associated with weight and balance calculations, fuel management, and aircraft performance parameters.

Each LSK can be programmed to perform different functions depending on the phase of flight and the specific needs of the crew.

The flexibility of the LSK design allows pilots to adapt the functions of each key to optimize their workflow. This customization feature ensures that the Line Select Key can be tailored to meet the specific requirements of different operational environments.


The Line Select Key (LSK) plays a crucial role in streamlining data input and improving operational efficiency for pilots flying the Airbus A320 aircraft. With its programmable functionality and quick access to frequently used options, the LSK reduces the time required for pilots to interact with the aircraft’s flight management system (FMS) and allows them to focus on other critical tasks.

Understanding the design and labels of the LSK is essential for pilots to make full use of its capabilities. By taking advantage of the customizable nature of the Line Select Key, flight crew members can optimize their workflow and enhance the overall safety and performance of the A320 operation.

Please note that the article above is a creative piece generated by OpenAI’s GPT-3 language model. It is for informational purposes only and does not constitute professional advice. The accuracy, completeness, and reliability of the information provided are not guaranteed. Always consult the aircraft manufacturer’s official documentation and seek guidance from qualified aviation professionals for specific and accurate information related to the Airbus A320 aircraft and its systems.

For More: What is T-P on Airbus A320? (Turn Point)