Originally Posted by
A0283
at 14:20:55 Guangzhou area control radar showed a "deviation" Command altitude" warning, the aircraft left the cruise altitude
Interesting terminology (with allowances for Google auto-translate).
The phrase "deviation command altitude" sounds like a reference to Selected Altitude - a parameter that is increasingly available to ATC in many (most?) parts of the world via Mode S/EHS, intended to allow controllers to pick up discrepancies between selected FL and cleared FL.