Originally Posted by
RifRaf3
Of course 6000'/min is possible for an updraft, but gliders do not stall when they enter thermals. They gain total energy, The ROC mentioned is adequately explained by trading speed for height. There equally could have been a slight downdraft.
6000 fpm unexpected in an Airbus with a change of Outside Air Temperature? Not at all impossible indeed its happened before.
For 18 seconds after the autopilot disengaged the aircraft remained within 200 feet altitude of FL
360 but once AoA law was invoked at 14:21:50 hrs, the aircraft's attitude began to pitch nose-up.
The pitch-up trend continued for 17 seconds reaching a peak of 15° nose-up shortly before the first
nose-down sidestick command was applied. Throughout this phase the aircraft climbed rapidly
(reaching a peak rate of about 6,000 ft/min) due to the increase in lift created by the flight control
system's capture of alpha prot. The aircraft reached its apogee at FL 384 at 14:22:28 hrs where the
airspeed had decayed to 205 KIAS and 0.67 Mach even though full thrust had been applied.
Throughout the turbulence encounter, the normal g fluctuations were between 0.5g and 1.5g. The
recorded wind direction remained within 20° of the mean of 240° but the wind speed varied
between 67 kt and 108 kt and the static air temperature fluctuated between -42° C and -52°C. There
were 7 cycles of temperature change, the second cycle being the most severe. The mean air
temperature before the AIRPROX event was -46.5° C and afterwards it was -44.5°C. The crew
subsequently descended back to FL 360 and successfully re-engaged the autopilot and autothrust
systems.
http://www.rvs.uni-bielefeld.de/publ...pdf_501275.pdf