- On an FSX native aircraft, when the wing contacts the ground there is a corresponding sound and the aircraft rolls in the direction of that wing
- On an FS9 portover, when the wing contacts the ground it appears to break off in addition to the above
- When you slew the aircraft up after this, the aircraft enters an uncontrollable spiral whether or not the wing visually disappears
- The same spiral occurs when a wing failure is triggered through a mission
Wingtips are, or at least should be equipped with scrape points in the [contact_points] section of the aircraft.cfg. Scrape points possess a link to a sound file that is played whenever one contacts the ground and it will trigger damage to the associated "part" above a certain vertical speed.
I don't know what exactly happens visually in FS9 but I still think that the FSX model parser ditched the feature and therefor, you won't see parts breaking off.
Flight dynamics-wise, since MSFS knows the relative position of a scrape point from the aircraft's datum reference point, it may apply a permanent, additional moment in that axis after incurring damage. Hence your observation of a roll.
This is based on your observations, the documentation on contact points and counting 1+1 together. You'd definitely have to do your own further investigation though.
https://msdn.microsoft.com/en-us/library/cc526949.aspx#mozTocId836373
The FS9 SDK mentiones damage textures at various points (GMax Aircraft Creation, GMax Materials, MakeMDL) as well as compiler flags used to include or exclude said textures.
The MakeMDL documentation has a table of parts eligible for damage textures on page 13. It basically says that parts of the model that are named as stated in the table will switch to the damage texture if it impacts the ground.
It might be that, when no damage texture is present at all and the "ignore damage texture" flag has not been set during compilatiuon with MakeMDL, the part will simply become invisible instead of displaying the damage texture.
You can very well prove me right or wrong by creating a flashy version of the regular texture, give it an eligible name (see documentation previously mentioned) for a damage texture and crash the plane into the ground. If the texture switches, I was right, if not there's more to the matter than the FS9 SDK discloses.
By the way: The visual_damage flag is still documented for aircraft.cfg files in FSX/ESP, but the modeling-related part of the SDK makes no mention of any damage capability whatsoever. Therefor, the flag is basically dead weight for native aircraft.
This means that developers, desperate to provide an edge over their competitors, have been unable to document a variable that triggers partial structural failures. If one or more of these developers has discovered this variable, he is not even advertising his unique ability to provide a visual representation of structural damage.
The documentation I was referring to is the official one included in the SDK. See here:
https://msdn.microsoft.com/en-us/library/cc526981.aspx
Also, try to come up with a single FSX native aircraft that features visual damage. I can't name one.
An actual visual damage feature wouldn't stay much of a secret for long to boot because curiosity not only kills cats but also makes for great reverse engineering.
Based on that there would be no way to check the state of the wing to answer the original question. The .mdl file is only geometric, if it is modeled to have parts fall off in FS9 or CFS, that process has absolutely no affect on the air file or the aircraft.cfg which is where all the basic data; aerodynamic, weight, power, etc is stored.
I have done similar tests to those performed by TurboCompound and have not had results that appear to be a lost wing.
No additional moments in the direction of an axis?
This is simply not true. There are addons available that attempts to represent visual damage, one of them is called "FSX Aircraft Inspection Mod." Perhaps TurboCompound is using one of those as it would be the only way to accomplish what is described. It is rumored that Microsoft removed crash damage as a concession to real world aircraft manufacturers like Bell, Robinson and Maule in consideration for their products being represented in a simulator and that rumor carries much more weight than a lone claim that crash damage is indeed represented.
Unless an aircraft is specifically equipped for that, any third party mod featuring component failures only affects FDE and systems, not the visual model.
I've never heard of that rumour before. It does have a bit of substance though, regarding some manufacturer's attitudes towards consumer level flight sims. My personal explanantion is that the restoration of visual damage was deferred to concentrate on more pressing issues (performance, DirectX10) and ACES never got around before they were axed or that they simply didn't bother anymore because only a small part of FS9 addon aircraft actually made use of the feature.
