OK, here is Captain Nixon's (greatly) summarised hypothesis. I'd forgotten, but on re-reading found he'd 'Recapped' the Analysis and Conclusion chapters. Here they are for comparison with previous posts. Nixon published The Crash of MH370 in 2017.
Analysis recap:
• Lethal smoke, source unknown
• Captain disconnected the autopilot and tried to turn towards Penang and the FO tried to complete the initial ‘Smoke, Fire or Fumes’ actions before putting on their masks
• Both succumbed to smoke before managing to do that
• The aircraft continued without the autopilot, and at the mercy of the elements. Its in-built design stability kept it flying.
• If it encountered severe weather its heading may have been affected
• With TAC operating, even with no autopilot, the end-of-flight scenario assumes a 15nm radius from the double-engine flameout entering the water, the intersection of the 7th arc at 35 degrees south
• With no TAC and no autopilot operating, the end-of-flight scenario may assume the left engine operating at cruise power, possibly a higher rate of descent and a crash site within a 40 nm radius of the first flameout entering the water, the intersection of the 7th arc at 35 degrees south.
Conclusions recap:
• The pilots performed as well as any other crew
• An emergency event developed, disabling ACARS, transponder, and radios
• Recognizing the urgency, the captain disconnected the autopilot to decrease his turn radius to fly to Penang
• Both pilots were overwhelmed by lethal smoke
• The aircraft’s progress was affected by the weather
• The inherent stability of the 777, and its inertia, caused MH370 to fly for so long by itself
• Simulator modelling will be required to determine how the aircraft would have performed with the autopilot off
• The main debris is most likely located in the area suggested by Dr. David Griffin, within a radius of 40 nm at the intersection of the 7th arc and 35 degrees south. His position has been strengthened by the use of an actual Boeing 777 flaperon in tests in the seas off Hobart, and also by drift modelling done
by the University of Western Australia.
For those interested, here’s the Table of Contents:
The Crash of MH370, Reviews, Library Page, Legal Disclaimer, Dedication, Foreword, Introduction, The Known Facts, The Players, The Pilots, The Flight, Losing Contact, The Search, Theories, My Analysis, Conclusions, Recommendations, What's Next? Acknowledgements, Additional Reading/Viewing, Appendix, List Of Abbreviations, Glossary Of Terms