Ian W;
While I agree with all that you say regarding the ITCZ, the key, (and I know you and many here, know this), is vigilance and avoidance, regardless of route.
The thunderstorms in northern Canada differ markedly from those in the Caribbean and while one gives those in the Caribbean (and the ITCZ of course), more berth, both are avoided with as wide a margin as possible, commensurate with one's clearance, (to be clear, it is rare that the emergency authority of the commander must be used to deviate from course or altitude without a clearance).
The circumstances where one has no options and must pick the best route out of a number of equally bad choices are rare but they do occur.
The primary defence against surprise is the constant and knowledgeable use of radar for as long as necessary, bearing in mind two facts about the return signal - that it is moisture that returns the signal* and that TCu's can be hidden from radar by stronger returns closer in.
On June 1, 2009 on the first thread (before it was quickly closed, as it should have been!), and based on experience as well as what
Dave Gwinn (RIP) has had to say on
radar tilt management (among many things he's said), I posted
some comments on the use of radar. I believed then as I do now that the use of radar was not well understood and is poorly taught to airline pilots who must get their knowledge informally as well as through manufacturer's brochures. I think airlines just assumed that "pilots knew", just as they assume all their pilots understand a bit about high altitude, high Mach Number, swept-wing aerodynamics. The one superb source on the intelligent use of today's radar was Dave's work who has written. Along with Trammel's work, at the time it was the best information available. In keeping in touch with what some airlines are doing, I see that much more information is now available in FCOMs. PPRuNe is a good source, as always.
In my experience with the ITCZ there wasn't always a way to avoid all weather so one picked one's way using radar for long-term planning, (A330/A340 radar - 160nm scale, varying tilt to take slices, making calculations of height, watching the changing picture, changing the gain but staying mostly on AUTO), and by watching outside for possible routings. Turbulence was a regular occurence and occasionally long-term characteristic of flight through the ITCZ (Pacific). Sometimes we'd get hammered, very sharply, sometimes when we expected to get hammered the ride was smooth. Diversions were routinely done.
The introduction of CPDLC was in my view a tremendous safety enhancement for such diversions and altitude changes.
Regarding AF447, it is difficult to come to any solid conclusions regarding their choice of routing. They did discuss altering course and indeed did so to the left, without an ATC clearance. In my view the turbulence indicated in the data was not unusual, (1.25 to 0.8g).
To my knowledge, the notion of
sleep inertia on the part of the PF has not been widely discussed but the UAS event occurred within about ten minutes of the call to the flight rest where he was sleeping. It will be interesting to see if the Final Report addresses this issue, as it is a known human factors matter.