Sorry to be a bit vague, but I seem to remember a story going back to the 50s or perhaps early 60s, where an aircraft (DC4/ 6 ?) flew through fuel being dumped and crashed killing all on board. I gather there were a lot of school kids on board and this brought in new rules about dumping.
Does anyone else remember the story?

Off chocks
 

Iirc think it was in the states and possibly a military air show