How many years did he fly BA planes safely?
This may not be relelvant. There are at least two crashes involving a commercial aircraft where the cause has been deemed to be the suicide of one or other of the pilots. (Silk Air 185 and Egyptair 990). I have tried to find information regarding the length of time these pilots had been flying for the particular airline but haven't succeeded. Simply because someone has flown for an airline for years does not automatically mean he or she will never resort to deliberate, lethal behaviour when flying.