Hello,
Thank you for reporting the issue.
We need crash dump files from this folder for solve your problem.
C:\Users\<Name>\AppData\Local\Arma 3\
Can you upload somewhere in winrar package please?
When package will be smaller than 5000k, you can attach it here. When package is bigger, please use some free sharing service and post link here.

How to find correct crashdump file:
Try to make the crash happen
Look into crashdump folder
Upload crashdump with latest date in name (crashdump is rpt + bidmp + mdmp file with same name). Please try to provide as many crashdumps as possible, it helps us investigating the problem in a big way.

Thank you.

http://feedback.arma3.com/how-to-user.html

Every crash occurs when enemy AI is engaged. Successfully navigated mission and all functionality for four hours. However the instant I engaged the enemy the server crashed. I tested this out over several missions with and without NPC's and the result is the same.

My appdata folder is empty. It does not generate a crashdump.

It should at least create a rpt file. Do you use any mods?

Iv had this exact issue as well. My test was however spawning 2 fireteam of seperate factions and not even after 5 secs of fire does the server crash. I'm using a linux server with multiple addons which may very well be the cause. I did test locally with same mission and mods and same issue. I do have the rpt and minidump files however im not at home right now so il post them wen i do. Linux rpt file didn't create any errors just before crash so im assuming that it didn't log the errors from memory.

Edit- wat are some of the mods u are using? I'd love St ours but we use alot.

It is looking like some client side mods are the blame for the crashes. I went vanilla with ArmA3 and rejoined the server and it seems to be working. Most of my mods were weapons mods like the MK18 Mod1 and the RH packs which I suspect with the new ballistics in the game might be why the server was getting confused and decided to go take a nap.