Chris S, gums, Turbine D, takata, airtren, this paper may have been referenced before but if not it may be of interest in the present discussion, and also in the ongoing discussion regarding "Why the pitch-up?": "
The Effect of High Altitude and Center of Gravity on Handling Characteristics of Swept-wing commercial airplanes"
syseng68k;
Thank you for your response. Some of this has been discussed thoroughly before, but some has not - the following summary, part way through the Boeing paper referenced above, advances the point I was trying to make regarding training, knowledge of High Altitude flight and transport characteristics.
Believe me, these notions are not discussed in any groundschool I have ever had from start to retirement - "NTK" was, and is, taken seriously by cost-conscious beancounters, (as you say), but even in recurrent, none of this is discussed - it is assumed (self-study is fine, but materials the deal with the issues but which aren't academic papers, are scarce) - and in fact, accident reports and FOQA trends are never discussed either. Here's the relevent section, (my emphasis) - kindest regards, PJ2...
Summary
The use of wing sweep and stability augmentation on modern commercial airplanes makes them more fuel efficient. However, flight crews must understand the effects of CG and altitude on performance and handling qualities. For example, operating at an aft CG improves cruise performance, but moving the CG aft reduces static longitudinal and maneuvering stability. Many modern commercial airplanes employ some form of stability augmentation to compensate for relaxed stability. However, as long as the CG is in the allowable range, the handling qualities will be adequate with or without augmentation. An understanding of static and maneuvering longitudinal stability is an essential element of flight crew training.