Dropped a Bell UH-1H C&C helicopter once......the Doughnut at the top of the recovery sling (the bit that actually rode inside the cargo hook of the Chinook) broke....and away off went the Huey.
It had less than 25 flight hours on it at the time....and was being recovered due to a hydraulics failure.
Some Einstein in his infinite wisdom decided since there were Chinooks headed south to our base at Chu Lai....why not just sling the Huey back rather than fly a Huey and Maintenance Team north to there grounded aircraft that was in a "safe" base camp with an airstrip.
It was after dark and out over the South China Sea....cruise altitude of 3000 feet.
The Huey did not survive that drop test.
We made darn sure we retained the broken Doughnut as evidence as we just knew some Colonel whose ride it was that got dumped would be looking for some heads to lop off.