script.sqf

params ["_unit","_damagedPart","_damageDone","_sourceUnit","_projectile"];

// Define to-be-damaged parts.
_meme = [meme1, meme2];
_tailrotor = "mala vrtule";
if (_projectile != "FakeAmmo") exitWith {_damageDone};
if (((random 100) / 100) <= 0.2) then {
    {
        _x setHit [_tailrotor, 0.8];
        _x removeAllEventHandlers "HandleDamage";
    } forEach _meme;
};