Flying is not inherently dangerous, people are....
-Anonymous
Eventually 99% is human error, mostly on the pilot side.
The remainder is maintenance errors, lackadaisical attitudes on the part of ATC, refuelers, rampers, examiners and even (human) design flaws.
All accidents are a chain of events and components with causal effects and some accidents are years in the making before all the links connect.
The Teterboro Learjet crash being a perfect example of all the ingredients of an accident.
At any time any link could have been broken and the accident would not have occurred.
https://www.flightglobal.com/news/ar...ro-lea-456614/