Nice post from error_401.
It occurs to me that no one (including me) has yet cited the certification requirements, although I have referred to them. The definition of "stall" is in CS 25 201 (d). See also the accompanying comments in AMJ 25 201. The current document is downloadable from
The EASA Certification Specifications WWW page. I should point out that most transports in use today were certified to forerunners of this document, not this precise document, and that engineers are very particular as to precisely which version of the document a given aircraft was certified to.
Notice that none of the characteristics in CS 25 201 (d) refer to C_L_Max.
Notice that stall characteristics are only required to be demonstrated from (a) level flight, at low speed (so, Vs1g stall), with engine power appropriate for a slow deceleration rate; and (b) a moderate level banked turn under similar conditions.
PBL