Spitballing here.
Jack is often short for John and there was a power outage on Martha's Vineyard the night of his plane crash.
Anon's outta free NY Times articles, it's in there tho.
https://www.nytimes.com/2000/07/07/nyregion/safety-board-blames-pilot-error-in-crash-of-kennedy-plane.html
2 days ahead.