Somebody mentioned the way out by seppuku or harakiri as a way out. Sigh, that way of bushido is only honorable if there is no other way out. As babablackshiep's old instructor is still breathing, he has other honorable ways to make amends. He can write to the affected pilots' airline or the aviation authorities explaning his gross error...I am sure his signature and examiner licence number will be recognised.
He is still able to make amends...do something! Crying and confessing is good but really doing something about it will be precious, not only for himself but for the people he had wronged.