Quote from
DJ77:
"Please, what is this transition from g-control to pitch-control you are talking about and where is it described in the FCOM? Does it apply to A-330?"
Sorry for the sluggish response. If you thought you detected some hesitance or vagueness in my glossed-over references to C* (PITCH) law, you were right. The reason is quite simple: my only source of information is an extract from an A320 FCOM dated August 1987, six months before A320 type-certification, headed "British Caledonian" (joint launch-customer with Air France), which I obtained a few months later for my type conversion. That admitted, I doubt the fundamentals of C* law will have changed much in the meantime. But it amounts only to a brief introduction for us line pilots.
To answer the second part of your question first, Airbus have deliberately provided all their FBW aircraft with similar handling characteristics. A330 and A320 speeds are, I think, broadly similar. For example, on the A320, 210kt IAS is a typical "clean" holding speed below FL200, which has to be increased by 10kt or so at maximum landing weight. I doubt the A330 is greatly different. So the speed criteria used in C* are likely also to be similar.
My old FCOM says that C* law uses
"normal acceleration as the basic parameter. At low speed, pitch rate is mixed with load factor [i.e., normal acceleration] 'G' such that at less than 150kt the effect of both G and pitch rate is [sic] equal. Above 210kt pitch-rate effect on the flight path is zero."
Later, it continues:
"The overall effect of the law is that with the [sidestick] controller at neutral, the aircraft will maintain 1G and zero pitch-rate at low speed and 1G at high speed. As a result the aircraft is short-term attitude-stable."
[my hyphens, and my comments in square brackets]
In relation to AF447, I commented
yesterday:
"The other unclear factor is how the C* pitch-function of the EFCS would treat the invalidation of CAS (IAS) data, when determining the crossover from g-control to pitch-control. As I understand it, that crossover is normally a gradual transition as the airspeed falls below a certain figure in routine flight. Understanding how the UAS affected this will be the other key step in solving the relationship between sidestick position, elevator/THS position, and the achieved trajectory."