I just watched video explaining how the American Airline Flight 587 crashed
It led me to think about glider flying. The cause of that crash was that the first officer aggressively and unnecessarily applied full rudder left and right in turbulence, the air force against the moving rudder stressed the vertical stabilizer and caused it to snap.
Is such risk realistic in glider flying? If one encounters air turbulence in while flying glider, how to deal with it, and what to avoid?
Is such risk realistic in glider flying?
What does "realistic" mean to you? If it means "could it happen" then sure, it could. Plenty of things could happen. If a possibility greater than zero is all it takes for you to worry then by all means, stop reading. Don't forget your shark armor and anti-meteor hard hat when you go out next.
However, most people consider "realistic" to include likelihood. Is it likely? Well, I searched through the last 8 years(1) of the NTSB accident database for glider accidents involving the term "breakup". Of the three relevant results, two involved aerobatics. How many glider flights have there been in the last 8 years? Probably plenty of them. Do you plan to do aerobatics? If not, then your accident statistics are one in plenty. Only you can decide if that's too scary for you.
It is not on the NTSB 10 most wanted list. I have not read about it in FAA Safety Briefings.
In my experience, new students don't know what is important, so as a proxy, they worry about things that are vivid. In-flight structural failures that have videos made about them are highly vivid. That's why my original answer started out by saying "this is not a valuable use of your attention". If I were your instructor, I would advise you to focus your concerns on flying proficiently and learning good decision making. If you do that, the concerns here will take care of themselves.
If one encounters air turbulence in while flying glider, how to deal with it, and what to avoid?
There is no "if" here. You are definitely going to encounter air turbulence. That's how you know you're doing it right.
How to deal with it? Pay attention to your instructor, monitor your attitude, remain calm, and fly the aircraft.
(1) - Why 8 years? Because I got bored.
First of all please put out of your mind "the first officer aggressively and unnecessarily applied rudder". The pilot did what he was trained to do. "Agressively" applying rudder can save your life if you are in an incipient spin. The rudder is your friend.
Equally important, the pilots must be familiar with the limitations of the aircraft. One cannot fly outside the safe envelope, which includes abrupt maneuvers which overstress critical components and can lead to catastrophic failure.
But there may be more than meets the eye here. Hopefully the design of the tail and maintenance records were checked as well. Although the aircraft mass played a role in isolating the stress to the tail (larger aircraft will accelerate more slowly to force: a = F/m), as compared with a smaller trainer, one might expect the tail not to fail. A B52 bomber famously lost most of its vertical stabilizer to wind side loading and actually landed safely. Air turbulence can be very powerful. Wake from a 747 is literally tornado like and needs to be avoided.
With a smaller aircraft, tail failure due to rudder application is not high in the risk department, but LOOK FOR CRACKS AND FATIGUE while doing your pre-flight and try to avoid conditions that may exceed the design of your plane.
