Hi PJ2,
Your two cruise-performance charts neatly complement mm43's graph of Mach/FL/CG/Wt/Load Factor – thanks to you both.
PJ2's charts confirm that, because of its thrust limitations, the A330-200 with CF6-80E1A3 engines is unlikely to be climbed to a cruise altitude where the available load factor is much below 1.4g. Optimum Alt tends to give something of the order of 1.5g, and Max Alt gives just over 1.4g at M0.82.
(I think this is fairly typical of current turbofan airliners with their very high bypass-ratios, although twins like the A330 tend to have a higher available thrust-to-weight ratio than 3-engined and 4-engine types. So – unlike some aeroplanes with low-bypass-ratio engines, such as the VC10 – cruise altitude is limited by thrust rather than by the wing.)
Quote from PJ2:
Just some comments on the trop; - the A330 rides the transition quite well even though, as you say, the ride can be rough.
I would say that temperature variations aren't wide enough to cause concern in terms of being too warm.
Having ridden the trop routinely for 30 years, and flown this route, I agree; and am not suggesting for a moment that a trop encounter could have been the prime reason for AF447's demise. If severe icing turns out to be the primary, it is unlikely to be associated with the trop; most likely to be found in storm cells well below it. That's why I'm curious to know where the trop was. mm43 has mentioned a figure close to FL360, only 1000ft above AF447; HN39 has quoted an estimate of 15295m (about FL500).
There is, however, one very remote possibility that I would like to dismiss. At a frontal line, the trop layer typically steps up or down abruptly and considerably. (There may also be more than one layer.) If it is a step-down, the aircraft could transit in less than a minute from severe icing below the trop to an encounter with it. If that transition happened to coincide with the PF trying to fly the aeroplane using the technique for flight with unreliable speed indications (thrust/attitude), the effects would add seriously to his workload and any confusion.
Chris