What is THS on Airbus A330? (Trimmable Horizontal Stabiliser)

The Trimmable Horizontal Stabiliser, commonly referred to as THS, is a critical component of the Airbus A330 aircraft. It plays a crucial role in maintaining the longitudinal stability of the aircraft during flight. The THS is responsible for controlling the pitch attitude, improving control efficiency, and reducing the workload for pilots. This article will explore the functionality and significance of the Trimmable Horizontal Stabiliser on the A330.

Control Surfaces and Operation

The Trimmable Horizontal Stabiliser consists of three major control surfaces: the main horizontal stabiliser, the elevator, and the trimmable stabiliser. The main horizontal stabiliser is fixed and provides the initial stability for the aircraft. The elevator, located at the trailing edge of the stabiliser, is responsible for controlling the aircraft’s pitch motion. It moves in response to pilot input through the control column, allowing the aircraft to climb, descend, or maintain level flight.

The trimmable stabiliser, also known as the adjustable stabiliser or THS, provides an additional means of controlling the aircraft’s pitch attitude. Unlike the elevator, which is directly controlled by the pilot, the THS is operated by an electric motor. It can be adjusted in flight by the flight control systems to trim the aircraft, i.e., to establish the desired balance between the aircraft’s nose-up and nose-down moments.

By changing the angle of incidence of the trimmable stabiliser, the THS controls the aircraft’s horizontal stabiliser. It allows the aircraft to maintain a desired pitch attitude without requiring the pilot to exert constant force on the flight controls. This feature significantly reduces the pilot’s workload, especially during long-haul flights where maintaining the aircraft’s stability for extended periods is crucial.

Benefits of the Trimmable Horizontal Stabiliser

The Trimmable Horizontal Stabiliser on the Airbus A330 offers several benefits for both pilots and passengers. Let’s delve into some of its advantages:

1. Improved Stability: The THS enhances the longitudinal stability of the aircraft, reducing the need for manual control inputs. This results in a smoother and more comfortable flight experience for passengers.

2. Fuel Efficiency: By fine-tuning the aircraft’s pitch attitude, the THS helps optimize fuel consumption. Maintaining an optimal angle of incidence reduces drag and improves overall fuel efficiency, resulting in cost savings for airlines.

3. Reduced Pilot Workload: The ability to trim the aircraft’s pitch attitude relieves pilots of the need to continuously hold pressure on the control column. This reduces pilot fatigue, particularly during long-duration flights, and allows them to focus on other critical tasks.

4. Enhanced Safety: The THS contributes to improved safety by providing additional control authority to pilots. In certain emergency situations, such as loss of hydraulic control, the THS can help pilots maintain control of the aircraft and achieve a safe landing.

The Trimmable Horizontal Stabiliser is an essential component of the Airbus A330, enhancing stability, fuel efficiency, and safety. Its incorporation into the aircraft’s design demonstrates Airbus’ commitment to delivering high-performance aircraft that prioritize the comfort and well-being of both passengers and crew.

For More: What is UASS on Airbus A330? (Unofficial Airbus Study Site)