BOAC: More 'imaginative thinking?'....
One area of confusion in my mind Chris S may be able to clear up. What I think I see here and from BEA is that the THS did not move from its cruise angle until the top of the zoom climb? Given that it is supposed that PF held a nose-up demand most of the way up, why not? There must have been a good 40 seconds or more of 'demand'.
Where the heck do you SEE that written?
From 2 h 10 min 05 , the autopilot then auto-thrust disengaged and the PF said "I have the controls". The airplane began to roll to the right and the PF made a left nose-up input. The stall warning sounded twice in a row. The recorded parameters show a sharp fall from about 275 kt to 60 kt in the speed displayed on the left primary flight display (PFD), then a few moments later in the speed displayed on the integrated standby instrument system (ISIS).
At 2 h 10 min 16, the PNF said "so, we’ve lost the speeds" then "alternate law […]".
The airplane’s pitch attitude increased progressively beyond 10 degrees and the plane started to climb. The PF made nose-down control inputs and alternately left and right roll inputs. The vertical speed, which had reached 7,000 ft/min, dropped to 700 ft/min and the roll varied between 12 degrees right and 10 degrees left. The speed displayed on the left side increased sharply to 215 kt (Mach 0.68). The airplane was then at an altitude of about 37,500 ft and the recorded angle of attack was around 4 degrees.
From 2 h 10 min 50, the PNF tried several times to call the Captain back.
So where are the "held nose up inputs"??? It's just NOT there. Why invent this?
The comment regarding the THS comes later. Read the note.