What is SID on Boeing 737? (Standard Instrument Departure)

A Standard Instrument Departure (SID) is a predetermined flight path that pilots follow after takeoff to safely navigate from the airport’s vicinity to the enroute phase of flight. SIDs are designed to ensure a smooth and efficient transition from departure to the enroute navigation phase, providing pilots with clear instructions on altitude restrictions, heading changes, and navigation waypoints. The Boeing 737, being one of the most popular commercial aircraft, adheres to various SID procedures depending on the departure airport and air traffic control requirements.

Why are Standard Instrument Departures Important?

Standard Instrument Departures are crucial for maintaining the safety and efficiency of air traffic operations. By providing pilots with standardized departure procedures, SIDs ensure predictable and orderly departures, particularly in busy airports with high levels of air traffic. Here are a few reasons why SIDs are important:

1. Enhanced Safety

Standard Instrument Departures contribute to enhanced safety by providing pilots with clear and concise instructions to follow after takeoff. These procedures outline the correct climb profiles, altitudes, and headings required to navigate the airspace safely and avoid conflicts with other departing or arriving aircraft. By following SIDs, pilots can minimize the risk of mid-air collisions, ensure proper separation from other aircraft, and mitigate the potential for human error.

Additionally, SIDs often include specific obstacle clearance criteria to ensure that the aircraft maintains a safe vertical clearance from nearby terrain or structures during the initial climb phase. These criteria are especially critical for airports located in mountainous or densely populated areas, where there may be significant obstacles that pilots need to avoid.

2. Noise Abatement

Another important aspect of Standard Instrument Departures is their role in noise abatement. Airports located near residential areas or sensitive noise zones often have specific departure procedures designed to minimize the impact of aircraft noise on the surrounding community. These noise abatement SIDs typically involve routes and altitude restrictions that help reduce the noise footprint during takeoff.

For instance, the Boeing 737 aircraft may be assigned a SID that requires a steeper climb gradient immediately after takeoff, allowing the aircraft to reach higher altitudes more quickly. This steep climb helps reduce the noise impact on nearby communities by keeping the aircraft at higher altitudes and away from residential areas during the most noise-sensitive phase of flight.

Implementing Standard Instrument Departures on the Boeing 737

The implementation of Standard Instrument Departures on the Boeing 737 involves several key components. Here’s a breakdown of the elements involved:

1. SID Charts

SID charts are graphical representations of the departure procedures specific to each airport. Pilots refer to these charts to understand the assigned SID, including the initial heading, altitude restrictions, and waypoints to follow. The Boeing 737’s avionics systems are capable of displaying these charts electronically, allowing pilots to easily navigate the departure path.

It is important for pilots to cross-reference the information on the SID chart with the aircraft’s Flight Management System (FMS) to ensure accurate navigation. The FMS stores the relevant waypoints, altitudes, and other procedural information for each SID, helping pilots adhere to the prescribed departure path.

2. Flight Management System (FMS)

The Flight Management System (FMS) on the Boeing 737 plays a crucial role in implementing Standard Instrument Departures. The FMS is a sophisticated computerized system that assists pilots with flight planning, navigation, and performance calculations. It integrates various data sources, including the SID charts, to provide real-time guidance to pilots during departure.

After entering the departure airport and assigned SID into the FMS, the system calculates the required climb gradient, altitude restrictions, and waypoints for the aircraft’s departure. The FMS then displays this information to the pilots, who can monitor their progress and ensure compliance with the assigned SID throughout the departure phase.

3. ATC Communication

Effective communication between pilots and Air Traffic Control (ATC) is essential when implementing Standard Instrument Departures. Prior to departure, pilots receive their assigned SID from ATC along with any specific instructions or altitude restrictions. Pilots must accurately read back the SID to ATC to ensure mutual understanding and compliance.

During the departure phase, pilots also communicate with ATC to receive instructions, such as altitude changes or heading adjustments, that may deviate from the standard SID procedure. These deviations may be necessary due to air traffic flow, weather conditions, or other operational factors. The ability to adapt to these dynamic situations while adhering to the overall SID structure is crucial for a smooth and efficient departure.


Standard Instrument Departures (SIDs) on the Boeing 737 are an integral part of safe and efficient air traffic operations. These procedures provide pilots with standardized departure paths, ensuring predictable and orderly departures while enhancing safety and minimizing noise impact. By following the assigned SID, pilots can navigate the airspace with precision, avoiding conflicts with other aircraft and maintaining proper vertical and horizontal separation.


1. “Standard Instrument Departures (SIDs).” Federal Aviation Administration, https://www.faa.gov/air_traffic/flight_info/aeronav/procedures/sid/. Accessed 15th June 2022.

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