[error]Expression    : fatal error
[error]Function      : CScriptEngine::lua_error
[error]File          : E:\stalker\patch_1_0004\xr_3da\xrGame\script_engine.cpp
[error]Line          : 73
[error]Description   : <no expression>
[error]Arguments     : LUA error: ...dow of chernobyl\gamedata\scripts\heli_combat.script:193: attempt to perform arithmetic on field 'change_dir_time' (a nil value)
 

stack trace: