1970, flying a HU16D (the military version of the sea plane you saw on fantasy island) from Guam to Okinawa. Port side generator went out ( I am the AE, electrician on the flight) then the starboard one went out (old carbon pile voltage regulators) so we were just running on the APU. I had the overhead compartment to the wing apart working on the right regulator, with everything totally hot, and luckily got it fixed.
Flying an old H34D Helicopter, we lost a tail rotor. My Captain was an old salt with lots and lots of hours. He instantly got the air speed up as high as it would go so the air across the fuselage kept the copter from going 360, and he landed that old magnesium thing at over 90 knots on the runway.
Lots of deals like this, but in Civilian aircraft there has only been one scary one. Weather like you described had the plane dropping 40 to 50 feet at a time instantly.