Law Three

Newton's Third Law of Physics; "To every action there is always an equal and opposite reaction", is well demonstrated when a helicopter loses it's tail rotor.

With the engines driving that mass of rotors around and around, keeping one up in the air by moving massive amounts of air via the magic of aerodynamics, the helicopter's fuselage requires something to deal with Newton's third law, otherwise it would simply spin in the opposite direction, making everyone inside quite dizzy and not really getting anywhere.  Hence the tail rotor.  These things are pretty safe, as the tail rotor is driven by the same transmission that drives the main rotor.  It's not something pilots spend any time worrying about, but in training sessions, as it's not outside the realm of possibility to lose one's tail rotor, we are taught to deal with it.  With a simple push of a button by the simulator operator, the crew looses it's tail rotor, the aircraft yaws quickly to the right, depending on the type of helicopter and which way it's main rotor blades spin around, and the fix is to take the driving force away from the mass of rotors spinning overhead, generally involving turning your engine off.  Problem fixed.  Now you are flying along, straight mind you, but with no engines.  Next problem; to avoid flying to the scene of the accident, straight of course as we've fixed the loss of tail rotor problem quite nicely.  Unbeknownst to most, helicopters fly quite nicely without engines driving the main rotors, but you are coming down, and fast.  As the pilot lowers his collective stick (actually he does this immediately upon recognizing the loss of tail rotor) the rotors now act like the seeds of a maple tree falling in the autumn.  The rotors keep on spinning, now driven by the rush of air forced up through them as we fall, but the pilot can still speed up and slow down and turn left and right, and as he nears the ground, pull the nose up to flare off his speed, and he only has one shot at the next bit; pulls on the collective, applying a massive amount of lift to the rotors to cushion the landing, but with no engines running, the rotors stop spinning rather quickly, so timing is everything.  Hence the sim and the practice.  These two boys pull it off very nicely.

And in the simulator at least, it's darn good fun.