(A usable air defence artillery.)

(Apparently, it can only be used by the members of the Elyos legion that took the fortress.)

(The air defence artillery seems to be in order.)

You use the air defence artillery. You finish the investigation.

(Usable air defence artillery.)

(Apparently can only be used by members of the Elyos legion that captured the fortress.)

You finish the investigation.

(Usable air defence artillery.)

(For some reason it isn't working properly.)

You finish the investigation.

(You use the air defence artillery successfully.)

(The air defence artillery skills can now be used.)

You finish the investigation.