Folks,
I think history will record the first instance of flutter in the stab of a Twin Comanche was during the UK ARB flight tests for a UK C. of A. Date about 1962 or 63. All this happened withing the aeroplane's normal operating envelope --- ie: Not beyond Vne.
I saw the aircraft after the incident, that the aircraft got back on the ground was a testament to the skill of the pilot, the CP of Air Couriers, the then Piper agents in UK.
As a result of the flutter, one side of the stab, from about the outer end of the servo tab, at an angle inboard to the leading edge at about a third semi-span had almost sheared off, and on the ground, part was folded back over the stab. After that, all Twin Comanches had an AD to strengthen the area, later incorporated in production.
The same pilot also survived a crash in a Apache, going around on one with gear and some flap out. You could see the aircraft shape where it went through the roof of an old barn on the extended centreline of RW 11 at Biggin Hill, coming to rest in the paddock just beyond the barn. Just as well all the roof timbers were about 300 years old. Both pilot and student only had cuts and scratches and bruises, not enough to avoid having to shout the bar that evening.
Tootle pip!!
PS: Loved the video, who did the animation. In the real case detailed above, the frequency of the flutter was estimated (from memory) to be 200-400cps.--- a "real buzz".