What is DEP on Boeing 737? (Departure Des Descent)

Departure DES Descent, commonly referred to as DEP DES, is a crucial phase in the operation of Boeing 737 aircraft. This process involves the controlled descent of the aircraft from its cruising altitude to prepare for landing. In this article, we will explore in detail what exactly Departure DES Descent is, its significance, and how it is carried out.

The Importance of Departure DES Descent

Departure DES Descent plays a crucial role in the safe and efficient operation of Boeing 737 aircraft. It is a necessary step that allows the aircraft to transition smoothly from cruising at higher altitudes to landing at the destination airport. During this descent phase, the aircraft gradually reduces its altitude, speed, and prepares for landing, ensuring a safe and comfortable arrival for passengers.

One of the primary reasons for the importance of Departure DES Descent is to comply with air traffic control regulations and maintain separation between aircraft. By following specific descent routes and procedures, pilots ensure that they maintain a safe distance from other aircraft in the vicinity. This contributes to the overall safety and efficiency of air travel, reducing the risk of mid-air collisions.

The Process of Departure DES Descent

The process of Departure DES Descent involves several key steps and considerations to ensure a smooth and controlled descent. Let’s take a closer look:

1. Initial Descent

Upon receiving clearance from air traffic control to begin the descent, the pilot initiates the initial descent phase. This involves reducing power, lowering the aircraft’s nose, and configuring the flaps and landing gear as necessary. By adjusting these variables, the aircraft starts to descend from its cruising altitude towards the destination airport.

During the initial descent, the aircraft typically maintains a high speed to cover more distance in a shorter time. This allows for efficient descent without compromising safety. Pilots rely on speed brakes and control surfaces to control the aircraft’s descent rate and maintain stability throughout this phase.

2. Controlled Descent

Once the initial descent is completed, the aircraft enters a controlled descent phase. In this stage, the pilot follows specific descent profiles and vertical speed restrictions set by air traffic control. These profiles are designed to ensure a safe and efficient descent, taking into account factors such as airspace congestion, weather conditions, and other air traffic.

During the controlled descent, the pilot continues to adjust the aircraft’s speed and altitude to maintain the desired descent rate. They may also make use of autopilot systems and vertical navigation modes to assist in maintaining a stable descent path. This helps in maintaining separation from other aircraft and achieving a precise arrival time.

3. Approach and Landing

As the aircraft nears the destination airport, it enters the final phase of the Departure DES Descent process: approach and landing. The pilot adjusts the aircraft’s speed, altitude, and configuration to meet the requirements of the runway and landing procedure.

During this phase, the pilot may also communicate with air traffic control to receive specific instructions regarding the approach and landing procedure. These instructions may include details about the runway to use, approach path, and any necessary altitude or speed restrictions.

Once the aircraft is aligned with the runway and at the appropriate altitude, the pilot initiates the landing sequence, which involves reducing the aircraft’s speed, extending the flaps, and deploying the landing gear. These actions prepare the aircraft for a smooth touchdown, concluding the Departure DES Descent process.


Departure DES Descent, abbreviated as DEP DES, is a critical phase in the operation of Boeing 737 aircraft. It ensures a safe and controlled transition from cruising altitude to landing, complying with air traffic control regulations and maintaining separation from other aircraft. Through a series of defined procedures and adjustments, pilots successfully navigate the descent process, ultimately leading to a smooth and comfortable arrival for passengers.

For more information about the Boeing 737 aircraft and its various operational processes, you can refer to the official Boeing website: https://www.boeing.com.

For More: What is OMS on Boeing 737? (Outboard Maintenance System)