How aircraft avoids turbulence and the importance of the weather radar system

Turbulence is a common concern for both pilots and passengers during air travel. It refers to the irregular and often unpredictable movement of air that can cause the aircraft to experience sudden jolts or changes in altitude. To ensure a safe and comfortable flight, aircraft employ various measures to avoid turbulence, one of which is the use of a weather radar system. In this article, we will explore how aircraft navigate around turbulence and the role of weather radar in enhancing flight safety.

What is turbulence and what causes it?

Turbulence is a phenomenon in fluid dynamics characterized by chaotic changes in pressure and flow velocity. It occurs when a fluid motion becomes disrupted and exhibits irregular fluctuations instead of flowing smoothly in parallel layers, which is known as laminar flow. Turbulence is commonly observed in various natural and everyday phenomena such as fast-flowing rivers, surf, billowing storm clouds, and smoke from a chimney.

The primary cause of turbulence is excessive kinetic energy in certain parts of a fluid flow, which surpasses the damping effect of the fluid's viscosity. In other words, the energy within the fluid overcomes its natural resistance to flow smoothly, resulting in chaotic and unsteady vortices of various sizes. These vortices interact with each other, leading to increased drag due to friction effects. Consequently, more energy is required to pump the fluid through a pipe or any other conduit.

Several factors contribute to the occurrence of turbulence in different contexts. Here are some common causes:

• Mountain Waves: When air encounters mountains, some air masses can crowd against the mountains, causing them to rise. These rising air masses can propagate as wide, gentle oscillations or break up into turbulent currents, leading to turbulence experienced in aircraft.
• Jet Streams: Jet streams are narrow, meandering bands of swift winds located near the poles. Differences in wind velocities as an aircraft moves away from regions of maximum wind speeds create shear regions that are prone to turbulence.
• Storms: Thunderstorms can generate turbulent conditions due to the disorderly air associated with them. This is a relatively new discovery by researchers. 

  

  Photo: CBC

  
  

The impact of turbulence on aircraft

The impact of turbulence on aircraft can vary in severity and can affect both the aircraft itself and the passengers on board. 

Turbulence is the irregular movement of air currents, which can cause the aircraft to experience shaking or abrupt changes in its trajectory. While turbulence is a common phenomenon experienced during flights, it is important to note that it typically doesn't pose significant safety risks. The vast majority of flights encounter turbulence to some degree, with most instances causing the aircraft to drop only about 20 to 50 feet in altitude, which is not substantial considering commercial airplanes fly at much higher altitudes.

Regarding the impact on the aircraft itself, modern airplanes are designed to withstand turbulence without sustaining structural damage. Whether constructed from materials such as aluminum, steel, or carbon fiber, the fuselage and engines are built to endure the effects of turbulence. Airplanes undergo rigorous testing and adhere to strict safety standards to ensure their ability to handle turbulent conditions without compromising their structural integrity.

As for the impact on passengers, turbulence can lead to discomfort, fear, and anxiety among flyers. Passengers may experience shaking during turbulent episodes. However, it's important to emphasize that  although turbulence can cause anxiety for passengers during flights, it is generally not a significant threat to the safety of the aircraft or its occupants.

Injuries related to turbulence are rare but can occur, particularly when passengers are not wearing their seatbelts. The majority of serious injuries from turbulence occur because passengers were not properly secured in their seats, often when they were moving about the cabin or using the restroom. Injuries can result from objects falling from overhead bins, passengers being thrown into seats or cabin structures, or collisions with food carts. It's worth noting that the use of seat belts is an essential safety measure to protect passengers from such incidents.

Photo: CBC

Pilot Experience and Reports:

One of the ways pilots stay informed about potential turbulence is by relying on their experience and information from other pilots. They often share reports of turbulence encountered during their flights through a system called the Aviation Routine Weather Report (METAR) and the Pilot Report (PIREP) system. This information helps pilots anticipate turbulent areas along their flight routes.

Weather Forecasting:

Another crucial aspect of avoiding turbulence is weather forecasting. Airlines and pilots rely on meteorological reports and forecasts provided by meteorological agencies to plan their flights and avoid turbulent regions. These forecasts take into account various factors, including the movement of weather systems, atmospheric conditions, and the likelihood of turbulence. Pilots receive updates on weather conditions at their departure airport, en route, and their destination, allowing them to make informed decisions about their flight paths.

Photo: Boldmethod

The Importance of the Weather Radar System in Aircraft

The weather radar system is an essential component of aircraft equipment, providing vital information to pilots about weather conditions along their flight routes. With the ability to detect and display convective weather patterns, including thunderstorms and associated turbulence, the weather radar system plays a crucial role in enhancing flight safety. This article will explore in detail the importance of the weather radar system in aircraft and how it aids pilots in making informed decisions.

• Detection of Convective Weather: The primary function of the weather radar system is to detect convective weather, such as thunderstorms. Modern weather radars, mostly Doppler radars, can detect the intensity and motion of rain droplets within cumulonimbus clouds. By analyzing the size of rain droplets, the radar system provides information about the presence of strong updrafts and associated turbulence. This capability enables pilots to identify hazardous weather conditions and make necessary course adjustments to avoid turbulence and maintain a safe flight.
• Real-time Weather Updates: The weather radar system provides pilots with real-time updates on weather conditions in their vicinity. The radar antenna, typically located in the nose of the aircraft, emits radio waves that interact with precipitation particles. The reflected signals are then processed by a computer and presented on a screen in the cockpit. Pilots can view the radar display, which includes patterns and color codes indicating the intensity of precipitation and turbulence. This real-time information allows pilots to navigate around turbulent areas, reducing the risk of encountering severe weather and ensuring the safety and comfort of passengers.
• Enhanced Situational Awareness: By having access to weather radar information, pilots gain enhanced situational awareness during flight. They can identify and track weather systems, including developing thunderstorms, from a distance. This awareness enables pilots to proactively plan alternate routes or adjust their altitude to avoid areas of significant weather activity. The ability to anticipate and avoid adverse weather conditions enhances flight safety and reduces the likelihood of encountering turbulence or other hazardous phenomena.
• Wind Shear Detection: In addition to convective weather detection, some advanced weather radar systems can also predict the presence of wind shear. Wind shear refers to abrupt changes in wind speed and direction, which can pose significant risks during takeoff and landing. By detecting wind shear conditions, pilots can take appropriate measures, such as adjusting their approach speed or selecting an alternative runway, to ensure a safe landing.
• Regulatory Requirements: Recognizing the importance of weather radar systems in enhancing flight safety, regulatory authorities have mandated their usage in certain situations. For example, EU-OPS 1.670 requires that aircraft operating at night or in instrument meteorological conditions, where detectable hazardous weather conditions like thunderstorms may be expected, must be equipped with airborne weather radar equipment. These regulations ensure that pilots have access to the necessary tools to make informed decisions and avoid potential weather-related risks.

The weather radar system is a critical component of aircraft equipment, providing pilots with essential information about convective weather patterns, turbulence, and wind shear. By utilizing real-time updates and enhancing situational awareness, the weather radar system empowers pilots to make informed decisions, avoid hazardous weather conditions, and ensure the safety and comfort of passengers throughout the flight. Its significance in modern aviation cannot be overstated, as it plays a crucial role in mitigating the risks associated