It's now more years ago than I care to recall, but we had a very close call at the Navy Test Pilot School with an HH-65. Seems the crew (who shall remain nameless, but it wasn't me) were doing pullups for testing maneuver stability. The technique was questionable, and while they were doing a pretty cautious buildup, they didn't realize that the limit light had a definite delay before illuminating.
On the pullup that bit, they pitched up to about 60 degrees nose up, and the rotor blades took a nice chunk out of the vertical stab (4 distinct cuts). They then proceeded to fall for 1500 feet with the controls all locked up (hydraulic system was unpressurized, and the flight path was effectively zero G to the airframe). Once the nose dropped to something 'normal' control was regained, hearts were restarted and they landed quite soon after that.
This of course caused a major kerfuffle, and we then proceeded to look at the HH-65 maneuvering capability. After much testing, it turned out that at cruise speed, you didn't get much over 30 degrees of bank before you would get the limit light, and God help you if you decided to do a violent pullup to avoid a flock of birds...