Inflight
turbulence
Inflight turbulence is an unsolved problem for aviation impairing comfort, safety, and economy of flight operation.
Existing solutions are insufficient:
The aviation industry aims to avoid turbulence by means of improving forecasts and weather models, as well as weather up- and downlinks. However, rerouting, change of flight level and logistic unreliability lead to wasting valuable resources, such as energy, CO2 emissions, and time. For a number of flights avoiding turbulence is not possible, especially for short-range low-level flights. A radical alternative for passengers to avoid inflight turbulence is switching to ground transportation.
Based on certification requirements, wings are reinforced to withstand typical gusts and turbulence. Still, to not exceed load limits the airspeed needs to be reduced in turbulent air to ensure structural integrity. Flying throught turbulence passengers are exposed to intense and rapidly changing accelerations, leading to discomfort and fear. Without seatbelt flight crew and passengers regularly get injured in severe turbulence, leading to the majority of severe injuries of airline flights and in some cases even to death. In consequence of constantly improving turbulence forecast and data, flight into known turbulence is likely to be restricted in future, similarly to flights into known icing or low-visibility.
Gust load alleviation systems aim to reduce wing root moments, commonly by symmetric aileron deflection. The so far achieved alleviation in the order of 10% is aimed to be further improved for envisaged structural mass reduction. Given its limited authority and reactive nature, so far considered control systems show no significant improvement of passenger comfort and are not sufficient to effectively cope with increased levels of atmospheric turbulence.
To substantially reduce the negative impact of turbulence, new solutions are needed, which sufficiently reduce turbulence loads felt by passengers.
Impact on Small Aircraft Operation
Small aircraft operation in low atmosphere is considerably affected by very frequent and strong turbulence typically present in ground proximity. Light weight aircraft are hit strongly by turbulence, similarly to feathers in the wind.
Assistance System with limited range and authority already sufficient
Common types and causes of turbulence
Clear air
Rapid changes in speed and/or direction near fast moving bands of air
Wake
When an aircraft passes through turbulence caused by an aircraft in front of it
Thunderstorm
Violent updrafts and downdrafts caused by storms
Mountain wave
When air is blown over a mountain causing updrafts and downdrafts
Impact on Advanced Air Mobility
eVTOL especially light, still fast cruise speed. Even more for the operation in urban canyon of very light vertical take-off and landing vehicle (eVTOL) as desired for advanced air desired for mobility (AAM).
Assistance System with limited range and authority already sufficient
Impact on Large Aircraft Operation
Avoiding turbulence
Climb to fly over
Descend to fly under
Slow down to fly through
Change route to fly around
Additional fuel means additional CO2 emissions
Needs fail-operational capabilities with sufficient range and authority
Inflight Turbulence
on the Rise
Global Warming: stronger winds, more thermal activity, jet streams