The recent tragedy involving a Singapore Airlines flight is bringing new attention to flying in turbulence. While pilots have encountered the hazards of unstable air conditions since taking to the skies, this latest incident has people concerned again about flying. I want to talk about turbulence and the role of weather forecasting in detecting it, but first let’s talk about safety.
Is Turbulence Making Flying Riskier?
Even with global air passenger traffic expected to reach nearly 10 billion by the end of 2024, surpassing pre-pandemic travel levels, death and serious injury resulting from turbulence rarely occur. The Federal Aviation Administration reports 163 passengers and crew were seriously injured by turbulence between 2009 and 2022.
A recent study from researchers at the University of Reading in England found climate change is making turbulence more frequent and severe because warming temperatures are strengthening the jet streams that cause turbulence. Clear air turbulence, which is more challenging to detect, increased by 50% between 1979 and 2020.
Based on the research alone that the occurrence of turbulence has increased, one could argue that flying may become riskier. I suggest that our continually improving forecasting ability and integrated technology make flying around turbulence safer. I will describe why later, but first a lesson in air dynamics.
Different Kinds of Turbulence
There are three general types of turbulence: boundary layer, mountain wave, and clear air turbulence, the latter is especially hazardous for pilots, crew, and passengers.
Boundary layer turbulence is caused by the interaction of a fluid with a solid boundary like the ground and features on the ground like trees, buildings, hills…etc. These features all have different degrees in which they inhibit airflow. This disruption of airflow creates what is called boundary layer turbulence. Boundary layer turbulence affects primarily takeoff and landing at aircraft at terminals.
Mountain wave turbulence is another type of turbulence caused by the wind blowing over mountains or hills. The turbulent air can cause airplanes to lose altitude unexpectedly.
Clear air turbulence (CAT) are erratic air currents that occur in cloudless air between altitudes of 20,000 and 49,000 feet. One of the main causes of clear air turbulence is strong vertical wind shear. One of the main causes of clear air turbulence is disrupted flow within a strong vertical wind shear environment. These disruptions are caused by bends in the airflow that produce what are called gravity waves. In very stable layers in the atmosphere, these waves can amplify in localized regions within this environment to the point that the waves break. These waves can be of the ideal size to disrupt an aircraft in flight at varying degrees. The highest degrees are considered severe turbulence.
Simply put, it creates high-altitude bumpiness where there are no significant clouds or thunderstorm activity.
Can You Detect Turbulence?
The short answer is yes, but some turbulence is easier to detect than others. By its very nature, CAT is virtually impossible to detect with onboard instruments or the naked eye. Forecasting, observation and communication of the presence or probability of CAT has advanced dramatically over the decades. Today, the most common way to detect, or confirm, the presence of turbulence is when a pilot reports an encounter to air traffic control to inform other pilots. Some airlines have gone “high-tech” and are using aircraft sensed turbulence data to crowd source turbulence reports.
New technological advances, increased observations, such as satellite networks, sensors and turbulence reports, and sophisticated weather models provide more accurate forecasting before the pilot takes off. These systems can integrate high-resolution and frequently updated turbulence potential information into flight management and planning systems. By being alerted to potentially hazardous conditions, pilots can plan routes accordingly, potentially flying at different altitudes or a different route to minimize the impact of CAT.
During flights, enterprise weather companies can use the airline’s provided flight plan to set alerts that allow real time weather monitoring over the duration of the flight.
Why Are there Still Injuries Due to Turbulence?
According to my DTN colleague, Dave Berry, an aviation meteorologist and industry expert, the aviation industry has become better adapted to emerging weather risk technology and utilization in the aircraft. But, he points out, it still has a way to go.
“Building better interconnectivity between ground crews, air navigation service providers and the aircraft would help them be more situationally aware of changing weather risks and have more information to make decisions, before and during the flight,” Dave said.
For example, pilots can make better use of connected devices to get integrated real-time weather information displayed on the aircraft. This data can come from weather providers, from other aircraft sensors or reports from the airline operations center.
Better connectivity also means better and potentially earlier communication. From the flight deck warning pilots about potential turbulence before they take off to a pilot briefing the cabin crew before takeoff when turbulence is expected en route.
Dave foresees that “As flight planning becomes more sophisticated and systems on the ground and the air become more common, alerting systems can be more easily integrated into flight planning and flight following tools.”
The Singapore Airlines flight incident is a tragic reminder that weather will always be a volatile factor in air transportation. I’ve talked about better weather forecasting and integrated technology. There is one thing that experts say all passengers and crew can do and that is have your seatbelt on when not moving around the cabin or when the fasten seatbelt sign is on.
