Thanks guys.
Achille had a few victories prior to this one, but all unconfirmed. This one ironically was confirmed with no witnesses.
The Hun was skimming the tops of the trees. Trying to avoid radar? My initial thought was to fly on top of him and force him into the trees, but thought better of it. I still needed my wheels to land, this being DID. We both gained some altitude once my observer started shooting. Of course he could not reciprocate on his Aviatik.
Then something I've never seen the AI do before happened. He dove under me and stayed there, trying to match my course. My observer had no clear shot. With the low altitude he could not do this for long and eventually I pulled along side him and my observer finished him off with a burst from his MG to the tune of La Marseillaise. This sim never stops to amaze me.

"Take the cylinder out of my kidneys,
The connecting rod out of my brain, my brain,
From out of my arse take the camshaft,
And assemble the engine again."