יש התאמה בין מה דברי יובל לביין מה שמסביר אדריאן תומס מ PF:
Beautifully clear video of deep stall following release of big ears. This problem has been well-known since the 90s, when it resulted in a major law-suit following severe injury to a tandem pilot and passenger. The safety analysis involved deliberate re-construction of the incident, and the test pilots found that when you release big ears there is a significant chance that the glider will deep-stall even without any brake on. The problem is particularly severe if wing loading is low, and if conditions are turbulent or gusty. I am told that some gliders are more prone to it than others, but I have not heard of, or seen a pattern that explains which gliders are particularly prone - however, I have not heard any suggestion that particular manufacturers or particular certification levels are more prone to it than others. For example, I know of some comp wings that suffered this problem (Pendry's XXX proto), as well as the tandems, 1s and 1-2s mentioned in this thread.
The answer is to be very wary about doing big ears close to the ground, particularly if you do them at trim speed or slower, and it is worth remembering that releasing big ears during a landing approach is a known cause of serious accidents.
Cheers,
Adrian
