Captain left the flight deck in the hands of such low-time copilots.
Well, that's not how I would put it. Robert had more Airbus time than the other two combined.
Robert is the one that turned up the gain on the radar as soon as he got up there. The captain was negligent of monitoring the ITCZ activity and adjusting the radar gain and tilt accordingly.
Coffin Corner: The A330 with it's supercritical wing makes "coffin corner" a slightly different animal than it was in the 727 days—where Mach buffet was a real threat. The A330 on the other hand is performance limited more than MMO limited. But, pilots have not been educated on the characteristics of the modern airfoils where going critical Mach is much more difficult. Perhaps that's why Bonin apparently confused the shaking of the airplane due to low-speed stall with "some crazy speed" (Mach buffet perhaps). This is covered in more detail in my book "Understanding Air France 447."
The other very enlightening thing about doing stalls at FL300 is how completely useless the engines are in the recovery. Let's face it we're pretty close to full power at cruise anyway. Throwing the thrust levers up to TOGA doesn't do a damn thing (try it at cruise some time and watch the airspeed not move). That's something that practicing stalls in a jet plane at 5000 feet has definitely given many pilots the wrong impression of—since the engines work to fix the stall problem very nicely at that altitude. Hence 447's cry: "but we've got the engines, what's happening?" Some claim that the pilots didn't do
any stall recovery. I contend they did exactly the stall recovery they were taught in their A320 checkout (the only time they practiced them) : apply TOGA power and minimize loss of altitude. Stalls are a pitch problem, not a power problem.