Definitions
" ... fatal accident for OMNI. the plane was a total write off, the indian student had stiches on his forehead, the safety pilot was burned badly (1st degree burns)"
The term "fatal accident" is used by the media, not in incident/accident reports.
The aircraft:
If it's a hull loss then it's an aircraft accident.
The crew members:
1. There were no fatalities, only injuries.
2. Stitches on forehead and 1st degree burns covering 5% or less of the body are not classified as serious injuries.
Ref.: ICAO Annex 13; NTSB Part 830