For Me, The impairment defence is 'impaired' in itself for the following reasons:
AH was described and proposed as an Experienced (Ex) RAF Fighter Pilot (Harrier) and Instructor (JP3/5) RAF-1984/1996; as such, he should have been easily able to display a:
1. Good understanding of the effects of 'G' and other in cockpit physical effects (Hypoxia etc). Irrespective of terminology.
2. Proper understanding of aircraft performance under manoeuvre, relating to aerobatics: Base Ht, Top Ht, Min Spd, Max G, AUW etc and everything else in the ODM (or PDM as it is today)
3. Concepts such as 'Stall', 'G' Stall, 'Wing' Drop etc, (and, if an Instructor, be able to explain them and describe Recovery Actions.)
4. Integrity.
I personally think the defence won, against all of these.
Advo