What is HZ on Boeing 737? (Hertz (Cycles Per Second))

The frequency of oscillations or vibrations is an important aspect when discussing the performance and functionality of aircraft. In the case of the Boeing 737, one crucial measurement is Hertz, also known as cycles per second (Hz). Hertz is used to quantify the frequency of various components and systems within the aircraft.

In this article, we will explore the significance of Hertz on the Boeing 737 and how it impacts the aircraft’s operation. From avionics systems to automated features, Hertz plays a pivotal role in ensuring the smooth functioning of this highly popular commercial aircraft.

Avionics Systems and Hertz on the Boeing 737

The avionics systems of the Boeing 737 heavily rely on Hertz measurements to regulate and synchronize various operations. These systems encompass a wide range of electronic devices and software applications that ensure the safe and efficient operation of the aircraft.

One important aspect where Hertz is utilized is the digital communication systems onboard the Boeing 737. These systems, such as the Satellite Communication System (SATCOM) and the Data Link Communication System (DLS), rely on specific frequencies measured in Hertz to establish and maintain reliable communication with ground stations and air traffic control.

The SATCOM system, for example, operates within the Ku-band frequency spectrum, specifically in the range of 10.7 to 14.5 GHz (gigahertz), which corresponds to 10.7 to 14.5 billion cycles per second. By utilizing this frequency range, the Boeing 737 can establish seamless communication between the aircraft and the ground, ensuring the transmission of important data and messages.

Similarly, the DLS uses VHF (very high frequency) and HFDL (high-frequency data link) bands, which operate between 100 and 156 MHz (megahertz), or 100 to 156 million cycles per second. These frequencies are vital for the transfer of critical flight information, such as weather updates, navigational data, and clearance requests.

The Importance of Hertz in Automated Features

The Boeing 737 is equipped with various automated features that rely on Hertz measurements to ensure precise and efficient operations. One such feature is the Flight Management System (FMS), which is responsible for managing the aircraft’s navigation, flight planning, and performance calculations.

The FMS utilizes Hertz measurements in its inertial reference systems and avionics to accurately determine the aircraft’s position, altitude, and orientation. The Inertial Reference System (IRS) relies on Ring Laser Gyros (RLGs) that measure rotation rates in Hertz, providing precise movements and positional data to the FMS.

Additionally, the Autopilot System in the Boeing 737 also relies on Hertz measurements to execute precise control inputs. The autopilot modes, such as heading hold, altitude hold, and approach modes, utilize Hertz measurements to adjust the control surfaces of the aircraft accordingly. This ensures stable flight conditions, reduces pilot workload, and enhances overall safety.


Hertz, or cycles per second, plays a crucial role in the functioning of various systems and features on the Boeing 737. From avionics systems that rely on specific Hertz measurements for communication to automated features like the Flight Management System and Autopilot, the precision and efficiency of these systems greatly contribute to the aircraft’s performance and safety.

Understanding the significance of Hertz on the Boeing 737 allows us to appreciate the complexity and technological advancements incorporated into this iconic aircraft. As Hertz continues to be a fundamental unit in measuring frequencies, its importance in aviation operations remains undeniable.

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