I follow this thread since the beginning, i read every single post.
Machinbird says: (of post 4426/4427 -
link)
Quote:
"....Why not a simple deceleration into a stall with heavy turbulence and a cockpit full of warning lights as a distraction? It seems to fit the event time line better."
Overtalks answer to that:
Quote:
So the case for it having been a Mach Crit encounter is there (IMHO - and unless some of the cognoscenti have a contrary argument).
Why do we assume, that the icing up of the pitot-tubes and the subsequent automatic system-reactions contributet to an drastic increase in IAS followed by desaster?
A few thoughts to augment my question.
Would it be logical to assume, that icing took place not only within the pitot-tubes but as well on other critical aircraft parts/ surfaces as Flight-controls?
Would it also be logical, that the heated pitot-tubes would be the last parts being affected by icing due to the heating of those?
What would that weight increase be, how would it effect aerodynamic lift and how much would it increase aerodynamic drag?
How much elevator trim would be necessarya to counter those effects given a stable speed?
How much would the AOA increase to maintain level flight?
How much power is availabel at the given altitude to maintain straight and level under such icing conditions, or even accelerate, and if that is possible, how long would an acceleration take?
If my thinking concerning those questions above are correct (and forgive me, i have no practical expierience on heavies) AF447 might have picked up icing, autopilot compensates for loss of lift and increase of weight, thrust increases to maintain not only speed (the wrong one) but also to maintain altitude, and finally within short time autopilot and autothrust reach their limits to maintain controlled flight. Icing up of the tubes leads to the final desaster of droping an aircraft into the lap of the crew, which just has departed controlled flight.
I dont know the timeframe in which this could have happened to AF447 (if at all), in my F4 2 decades ago it came out of nowhere in a climbout in military power at around Fl 250. Even selected afterburner didnt help in maintainig level flight. It took me 10.000 feet down to regain full authority over my aircraft and being able to get rid of the ice.