He was only part way through his instrument training and experienced one of the more common killers in general aviation: flying into Instrument Meteorological Conditions (IMC). For those pilots not proficient in instrument navigation (like JFK, Jr.), it can be a sure killer, and in his case it was.
In that corridor there was another option which was to pay attention to weather reports and not fly into that soup in the first place. But Noooo!!!
Just like his daddy, he was very short on judgement and wisdom.