Originally Posted by wallybird7
Uncommanded 7000 fpm rate of climb”. Why I think that it was uncommanded.
When a plane is at max cruising altitude (35,000) which the crew noted because the temps were higher than forecast, and therefore unable to maintain a higher altitude, why would they intentionally try to do it? Why would they climb to a higher altitude when they knew they could not maintain it? In weather a normal climb should not exceed 1000 fpm. Beyond that you are out of normal control. Without access to the performance charts I can’t believe it would be possible to execute a climb at a higher rate than that.
The DFDR data released in the BEA Update point in the direction of an initial climb that was commanded but unintentional and unnoticed. The performance charts you refer to show the rate of climb obtainable at constant Mach and CLB power setting. The 7000 fpm was not sustainable, it was obtained at the expense of airspeed.
The meteorological analysis showed evidence of strong up and down drafts of up to 60-70 knots. Which translates into 6000-7000 fpm rates of climb approximately. Is it possible that the plane encountered a severe updraft that carried or pushed it up to a rate of 7000 fpm? Is it possible that the updraft or severe turbulence pushed the nose down at the same time the plane was gaining altitude? And if so, is it not possible that the trim reacted in the opposite direction?
The Meteo France analysis in Appendix 1 of BEA's Interim report no.1 states (values in knots added by me):
The strongest vertical movements are observed in the "tower" of the cumulonimbus in its phase of rapid growth, that is to say before the top reaches the tropopause and the anvil is formed. The upward speeds can then reach 110 km/h (60 kt) and the downward speeds 50 km/h (27 kt). The vertical speed can thus vary very rapidly inside of the cumulonimbus while crossing its "tower": variations of more than 70 km/h (38 kt) in the space of 2 km have sometimes been observed.
(and somewhat later):
Analysis of infrared imagery does not make it possible to draw a conclusion on the presence of extremely powerful vertical movements, associated with of the "overshoot" phenomena.
Tim Vasquez' analysis mentions that "updraft velocities of 20 to 40 kt occur occasionally" in oceanic equatorial cumulonimbus clouds.
There is no evidence at all that these updraft velocities existed in the CBs that AF447 was trying to avoid, nor that they were actually encountered.
In all my years in aviation there were no AoA indicators flying mostly all the A/C made in the US. It was/is all about Stall Speed.
The 1 g stall speed is obtained at 1 g at the stall AoA. It serves as a reference for operational minimum speeds such as take-off speeds, V1, Vr, V2, climb speed, and approach speed.
The stall itself occurs at the stall AoA, not at a particular speed, but at particular combinations of airspeed and "gee".