Yesterday I took the TBM930 for a flight crossing the Andes from Chile to Argentina. I had a 80 kts wind at 25.000 ft. The Turbulence was light to moderate throughout the flight over the mountains. When I reached the edge of the mountains and was about to start my descent I got struck by Severe Turbulence which overstressed the aircraft within seconds. Was that just some rare phenomenon or is the turbulence overdone in some scenarios?
In this particular instance I dont know, but if memory serves me well, BOAC lost a 707 over Mount Fuji due to severe turbulence. What I am NOT sure of though, is whether this was CAT -Clear air turbulence, or influenced by other factors. I have no doubt that others will clarify.
In the MSFS there is no CAT, nor NEEDED turbulences in the clouds, this has already been mentioned and discussed several times. the only turbulences that exist are those over the mountains, but whether these are partly exaggerated or not, I cannot specifically say here. I have never flown over the Andes!
You probably flew too fast. When expecting turbulence one lowers the speed. Conservatively you fly at around manuvering speed Va.
For the TBM930, Va is around 160KIAS (see POH).
The matter is discussed in more detail here for the Gulfstream G450. The general principles apply also to other aircraft.
https://code7700.com/g450_turbulence.htm
In general however MSFS has tuned down the severity of turbulences. It was discussed in length in several other threads here.
Right in the sweet spot for extreme turbulence. Crossing the Andes or any mountain range requires an understanding of the weather/winds and altitude relationships. Depending on where you were crossing, 25000 is WAY too low to cross a ridge like the Andes. Especially in 80 knot winds. A google search for āMountain Flying Trainingā, may be your next step.
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Considering how much turbulence is āturned downā, there do seem to be instances where the turbulence - or perhaps its effects - are too severe. mountain turbulence can for sure be pretty savage, as can CAT around jet streams. But total loss of commercial aircraft due to turbulence (āYOU CRASHED - You overstressed the aircraft and caused critical damageā) is thankfully practically unheard of in modern times.
This is not a new issue, weāve discussed it before over past months here and here and here.
What Iād really like to see is some representation of moderate turbulence in and around clouds (which we were assured the sophisticated weather engine is capable of modeling) ā¦ me and my expensive motion base would be very grateful!
There is another aspect which leads the sim to show you that you crashed. It is the rather simplistic overstress and failure model. Which afaik or experienced looks at your IAS and if you exceed Vne kicks you out. This is obviously not how airplanes fail. Meaning that the whole thing immediately comes apart when you hit the red line.
A last aspect comes to mind, which we had a while back, where discontinuities in atmospheric data leading to jolts in altitude and airspeed and when close to Vne also to a virtual crash.
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