1 Information
AI Helicopter Glitch refers to the instances of various types of unresponsive and anomalous AI helicopter behaviours which are common occurrences on modern computer hardware (CPU) models regardless of the operating systems.
Fortunately, the issue has been extensively researched and it is also quite easy to fix via multiple different methods. This particular problem only occurs in the original Urban Assault game engine.
The symptoms of the AI helicopter glitch only started to appear after the official support for the game had been already ended, so there was no official fix or patch created by the developers.
OpenUA (UA:Source) engine does not have this problem anymore since it is already fixed by default.
2 Overview
2.1 Signs & Symptoms
AI Helicopters do not obey orders, have problems with turning, and cannot track or follow enemies properly. They are often unable to move to directions other than upward, and when ordered to move they will uncontrollably gain or lose altitude at the spot. The issue only affects the AI-controlled helicopters and does not affect the performance of helicopters under the direct first-person control mode of the player.
2.2 Technical Cause
The AI helicopter glitch problem is caused by an obsolete threshold check in the code that processes mathematical helicopter rotations inside the AI layers. When an update time period (via delta-time algorithm) of frame ticks for rendering the display become sufficiently short, which happens on modern CPU models, the condition is never fulfilled and the AI helicopter rotation matrix calculation is not processed correctly.
2.3 Workarounds
Various workarounds exist to mitigate the problem; but only one method is recommended nowadays. See the Solution section below.
3 Solution
3.1 Applying the fixed/updated game executables patch
A brand new modern Helicopter Patch with the updated game executable files was created. This new helicopter patch is flawless and has no drawback unlike the other old workarounds. It should provide a definitive solution to the problem once and for all.
The download link for Helicopter Patch file can be found below. Before installing the patch, please check the Readme file first. It contains full instructions on how to apply the patch.
3.2 Download Link for Helicopter Patch
4 Important Note
Disclaimer Warning: If you are still using any kind of unverified 'helicopter patch' files sourced from uncertain origins that were made before 2016, specifically any type of 'patch mods' that are designed to directly alter/modify/replace the *.scr data (script) files in 'Data\Scripts' folder, then please remove those files from your machines completely as soon as possible!
These kinds of outdated, unverified custom-made patch files are not endorsed here, and will never work correctly on modern hardware. But they will still detrimentally affect or alter the original helicopter behaviours and properties in many unexpected (and often undesirable) ways, and adversely impair the overall physics and performance of the affected helicopters.
Moreover, since such files are technically modified game data, the game engine will detect those files and trigger the file mismatch warning as a potential sign of cheating on multiplayer matches. Therefore please make sure to delete any unverified 'patch files' beforehand!
If you are uncertain whether your game files contain any undesirable modified helicopter data or not, the new Helicopter Patch file also contains the fully original and default game data files; which you can apply inside the game folder to restore the original helicopter data.
5 Historical Methods
There were several legacy makeshift methods used to circumvent the helicopter bug. However, since the brand new Helicopter Patch offers the complete solution without any drawbacks, they have been removed now to avoid confusions and dissemination of outdated information.