Hi Juan,
I looked at your test data and found that if you use an XY coordinate system focused on your runway, the Obstruction Identification Surface tool will produce results better matching your CAD data. I tried this by making my own projection from the Transverse_Mercator one used by your dataset. You can do this in the ArcMap Data Frame Properties> Coordinate System tab. Select the existing coordinate system and right-click> copy and Modify. Give the new coordinate system a new, more local name, and edit the values for Central_Meridian and for Latitude_Of_Origin. I gave Lat/Long coordinates corresponding to the midpoint of the RunwayCenterline feature. Ensure you set your ArcMap data frame to your new local coordinate system.
Now You can use the Create Aviation Geodatabase GP tool to create a new Airports 18B geodatabase and set the XY coordinate system to your new local projection (and the Z coordinate system to the same used by your test data). Now when you run the Obstruction Identification Surface tool, output to the Airspace\ObstructionIdSurface. You can then use the Polygon To Line GP tool and look at the SHAPE_Length values in the output feature class, in particular see the 280 meter wide Runway Strip width that you reported. You can also use the Feature Vertices To Points GP tool and do some Measure tool measuring on the points.
There are distortions in a projection the farther away from its origin- in this case the intersection of the Central Meridian and Latitude of Origin. Your runway location is about 617 Km away from the coordinate system’s origin and I see about 1.2 meter difference in the Runway Strip width within this coordinate system. So it is best to make use of a more locally focused coordinate system.
David