Hi,
"What made him pull must be brought to light."
i think it will never be. the pilot will not tell you why he pulled and any data recordings can only answer what he did, not why he did this.
The actions of a man (supposed normal mentally) are always the results of a thinkink
To make this thinkink that will lead to his action he must have facts to analyze
Recordings (voice and datas) can show what facts he had
If his actions are inconsistent with the facts available to it .. one might conclude that his thinking was not good, or as a last resort .. it does not have all his mental faculties (were altered) during the thinkink
So .. if we have all the datas who were available to this pilot .. we can conclude if is thinkink was good or bad
So .. yes we will know "why"
It's only three answers to "why"
Bad thinkink
Good thinkink relying on bad datas
Mentally disturbed