Turbulence related incidents (CAT) and Special Air Reports

Recently you might have noticed that there is an increase in turbulence related incidents in commercial aviation. The two major ones recently that resulted in multiple injuries and one fatality:

• 21-05-2024 Singapore Airlines Flight SIA321 (1 fatality and 104 injuries) 
• 26-05-2024 Qatar Airways Flight QR017 (12 injuries) 

University of Reading in the UK reported that severe turbulence had risen by 55% between 1979 and 2020 on a frequently used North Atlantic route. They attributed this increase to changes in high-altitude wind speeds caused by warmer air from carbon emissions. In other words, climate change.

Handling turbulence is routine, usually we can anticipate it and switch on the seat belt sign, wake-turbulence from other aircraft, low level turbulence caused by weather or thunderstorms, turbulence caused by terrain features for example. 

But when it comes to CAT, it is very difficult to detect with a conventional radar, so our options are limited, we can rely on Special Air-Reports also known as PIREP (Pilot Report). It is very important and a major contribution to flight safety, to report moderate or higher turbulence if you encounter it. But it can hit you without warning during your normal cruise phase, as it happened with the incident flights as well.

Food for thought: In a situation like this, what happens if the pilots seat belt is not properly fastened while sitting at the controls?

4.12.3 Contents of special air-reports

4.12.3.1 Special air-reports shall be made by all aircraft whenever the following conditions are encountered or observed:

a) moderate or severe turbulence; or
b) moderate or severe icing; or
c) severe mountain wave; or
d) thunderstorms, without hail that are obscured, embedded, widespread or in squall lines; or
e) thunderstorms, with hail that are obscured, embedded, widespread or in squall lines; or
f) heavy dust storm or heavy sandstorm; or
g) volcanic ash cloud; or
h) pre-eruption volcanic activity or a volcanic eruption.
Note.— Pre-eruption volcanic activity in this context means unusual and/or increasing volcanic activity which could presage a volcanic eruption.
In addition, in the case of transonic and supersonic flight:
i) moderate turbulence; or
j) hail; or
k) cumulonimbus clouds.

Unfortunately, no. One of the common causes for high altitude CAT are jet streams.  And they are very beneficial for us. You can read more here.