What is DES on Boeing 737? (Descent – Fmc Page)

The Descent – FMC page, also known as DES, is an important feature on the Boeing 737 aircraft. This page is part of the Flight Management Computer (FMC) system, which is responsible for aiding pilots in various aspects of flight planning and navigation. The Descent – FMC page specifically provides pilots with essential information and tools to ensure a safe and efficient descent phase of a flight.

The Importance of the Descent – FMC Page

The Descent – FMC page plays a crucial role in the overall flight operation, as it assists pilots in managing the descent phase effectively. It provides them with vital information related to altitude, speed, and vertical navigation, allowing for precise control during descent and approach to the destination airport.

One of the key functions of the Descent – FMC page is to calculate the optimal descent path based on factors such as aircraft weight, altitude, wind conditions, and air traffic control requirements. This ensures that the aircraft descends smoothly while adhering to the necessary speed and altitude restrictions.

The Descent – FMC page also provides pilots with critical information regarding the descent profile, such as the top of descent (TOD) point. The TOD point marks the ideal location to begin the descent, and it is calculated by the FMC based on the input parameters and flight plan. Having this information readily available allows pilots to plan ahead and make any necessary adjustments for a well-coordinated descent.

Furthermore, the Descent – FMC page offers pilots the capability to manage the speed of the aircraft during descent. It provides them with the necessary tools to set speed constraints, control airspeed, and manage energy levels to ensure a smooth and stable descent. This is particularly important as it contributes to passenger comfort and overall flight efficiency.

The Descent – FMC page also enables pilots to engage the autopilot features for descent and approach phases, allowing for a more automated and standardized flight procedure. By inputting the appropriate data and utilizing the FMC’s capabilities, pilots can rely on the automated systems to execute the descent procedure accurately, reducing workload and ensuring procedural consistency.

Utilizing the Descent – FMC Page

When utilizing the Descent – FMC page, pilots need to input various parameters and verify the information for a safe descent operation. Some of the key elements that pilots input on this page include:

  • Destination airport
  • Descent speed constraints
  • Altitude restrictions
  • Wind conditions
  • Aircraft weight

Once these parameters are inputted, the FMC calculates and displays the optimal descent profile, including the TOD point and vertical navigation path. Pilots can then utilize this information to set up the autopilot features, calculate the descent speed, and manage energy levels throughout the descent phase.

The Descent – FMC page also offers additional features that enhance the pilot’s situational awareness and decision-making capabilities. It provides valuable information on the estimated arrival time, fuel consumption during descent, and any required speed adjustments to meet specific waypoints along the descent path.

It is worth noting that the Descent – FMC page on the Boeing 737 is designed to assist pilots in their decision-making process, but it does not replace their judgment or proficiency. Pilots are still responsible for monitoring the aircraft’s descent and making timely adjustments based on any unforeseen circumstances or air traffic control instructions.


The Descent – FMC page on the Boeing 737 aircraft is a vital tool that contributes to the overall safety, efficiency, and precision of the descent phase. It provides pilots with essential data and functionalities to plan and execute a controlled descent, ensuring a smooth approach and landing at the destination airport.

By leveraging the capabilities of the Descent – FMC page, pilots can optimize the aircraft’s descent path, manage speed and energy levels, and utilize autopilot features to streamline the descent operation. This not only enhances flight efficiency but also contributes to passenger comfort and satisfaction.

However, it is important to remember that the Descent – FMC page is a tool that assists pilots, and it should be used in conjunction with their expertise and decision-making skills. Pilots must always exercise caution, monitor the descent progress, and make any necessary adjustments to ensure the safety of the flight.

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