Text in force at CS25-28: from CS25-0, effective 17 Oct 2003.
The aeroplane must be longitudinally, directionally and laterally stable in accordance with the provisions of CS 25.173 to 25.177. In addition, suitable stability and control feel (static stability) is required in any condition normally encountered in service, if flight tests show it is necessary for safe operation.
ED Decision 2003/002/RM · Source