Flight Safety Flash - Thunderstorms - 19 August 2022
News item of 21 August 2022. Last updated on 15 September 2022: some information may have changed. Latest news
A timely reminder for this summer season: let us apply a rule everyone knows well, See and Avoid. See dangerous cloud formations and Avoid them…
Many air accidents have occurred near thunderstorms. It is often said that turbulence can be extreme inside a cumulonimbus and tear an aircraft apart.
© Météo France
In general, turbulence under a thunderstorm can be fairly light or even absent, but most crashes happen close to the ground when a pilot is caught out by wind shifts that cause a stall. A wind shift is a sudden change in wind direction, sometimes accompanied by an increase in speed or by gusts. It can be caused by various phenomena, including the passage of a front or a pressure trough, a downburst under a thunderstorm, a gust front ahead of a squall line, a katabatic wind, and so on.
Do not go within 30 km of a severe thunderstorm!
© Météo France
Cumulonimbus clouds are known to be extremely dangerous for air navigation, and it is recommended to avoid them as far as possible. They can be extremely treacherous, and an inattentive pilot can find himself in a very dangerous situation while flying in apparently perfectly calm air. Nevertheless, thunderstorms vary in severity. There is little quantitative difference between a nasty shower produced by a cumulus congestus and a small storm with 3 claps of thunder produced by a small cumulonimbus.
In general, thunderstorm-related accidents do not involve the aircraft breaking up but are the result of secondary effects, such as an aircraft battered by hail or whose wing has been ripped open by torrential rain. Forecasting the severity of a storm is not an exact science, and there are many cases where pilots have been caught out by underestimating the violence of a storm, which sometimes intensified abruptly.
Fly carefully, observing cloud phenomena and identifying the associated threats.
© Météo France
If you have any questions, remember to ask your club or your flight safety officer!
Aeronautically speaking.
