Such letters can often be pointless, since you could have a blemish free career with an airline, yet prang a single engine Cessna that you hire in your time off and a ‘No accident/incident letter’ won’t reflect that. It’s why a number of regulators won’t even give such a letter, since one can hold and use multiple flying licences and it’s impossible to keep track of what goes on.
As is the case with a number of Gulf states (Qatar and UAE included), you can get a certificate detailing any criminal convictions when you get your visa cancelled. This can be used to support any security clearance needed with your next job.