(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.

(A usable air defence artillery.)

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

You finish the investigation.

(A usable air defence artillery.)

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

You finish the investigation.

(You use the air defence artillery successfully.)

(You can now use the air defence artillery skills.)

You finish the investigation.