Small correction (on your EM Map, Version 6)
Column: 29100
Lig: 26000

Now an extract with Gengoult perimeter added (best guess based on cadastra references and street names)



And same exercice on Google (in red):



On the southeastern part, it's possible to see on the satellite image the emplacements of old hangar (different green tone), probably of the air base.
depending on the wind, the airfield was probably on the NortWest part (along the road), an approximate would be a 03/21, and on the Northern part (shorter) with an approximate 09/27.

Hope this help

Thanks!

One more question:
Where is "Ivontsec" located? (its somewhere NE from Toul, close to the September 1918 frontline).

PS:
Foret-de-Spincourt?
Billy? its noted as "Billy, France, but actually i found few towns with "Billy" name, and feelin myself lost

Sorry for "Ivontsec". I searched our most extensive database (1.7 Millions toponyms on France).... and found nothing.
It's either a bad writing... or a name that disapeared (abandonned village)

For Spincourt, coordinates are:
5°40'E
49°19'40"N
and on the EM map:
Col: 27000
Lig: 19100

For Billy... I take the correct toponym is "Billy-sous-Mangiennes" (there are many other Billy in France)
Then coordonates are:
5°34'25"E
49°20'N
And on the EM map:
Col: 26300
Lig: 19150

I think that "Forêt de Spincourt" is in fact "Forêt domaniale de Spincourt" which is located between Spincourt, Senon and Loison
Here an extarct of the EM map where I coloried the forest in Green.
(you can also see Billy on the extract)

VikS, perhaps "Ivontsec" is "Montsec" (there being a font issue, where the word's first letter "I" and the "v" should combine to be the letter "M")?

Montsec was a German strongpoint defense around this town's wooded heights due east of St.Mihiel, utilizing the Butte de Monstec. There's a memorial on these heights to the American combat effort during the St.Mihiel offensive.

Oh... I think you had a very good guess FlyRetired...

Yes, Montsec is 14 Km W of St-Mihiel, and coordinates are:
05°43'14"E
48°53'23"N

BTW, for searching French locations, an easy way is to use the GeoPortail
It's a "Google Earth Like" site, limited to French territory, but who has access to the full toponym database for the search (the 1.7 Millions toponym I was talking about).
Another plus is that you can display the French aerial photographs and the 1:25k scale map on the same screen with transapancy effects.
It's in French, but I think the few tools are quite easy to use for anybody.

There's an example of the output you can have (with map on 50% transparancy and aerial photographs behind)

This is just awesome stuff Rama!

Thanks for the link, and thanks for lending all your expertise to this project. It will be all the more accurate because of it, and I can imagine how much VikS and the guys at GT have probably enjoyed your continued support!

Thanks guys!

One more question:

Aviators Cemetery at Sebastapol

Its location? Maybe there is any photos of it?

Sébastopol? ... in Krimea as far as I know...

In France, it could be the name of a street or a place in a town.... but if we don't know the name of the city, it won't help much...