The National Transportation Safety Board, an arm of the government devoted to thoroughly unraveling every possible cause of fatal plane accidents, among other things, has released their report on the fatal 11/07/2017 crash of Roy Halladay’s light aircraft.
The report can be found here, along with their docket summary here. Neither is especially riveting. The docket is a list of all 18 documents filed by the NTSB, but report itself is a very clinical account of the last minutes and death of a widely beloved man, and is difficult to read.
In short, Halladay was under the influence of several drugs at the time of the crash, and was attempting high angle-of-attack maneuvers at low altitude. The aircraft performed as intended, the pilot did not.
The medical portion of the report concludes with this paragraph:
We all have our demons.
Rest in peace, Roy.
EDIT: Roy’s widow, Brandy Halladay, issued a statement in response to this report.