Vassili Zaitzev
Master Sergeant
if the stall was uncontrollable, no doubt the plane accerlated beyond it's safety limits. That may be why the plane broke up in midair.
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I caught the tail end of an interview with an Aer Lingus pilot on the news this eveneing, he was talking about the speed sensors on the airbus failing and the flight control system not knowing what speed the aircraft was going and hitting 'coffin corner'. Just googled it.
Wiki- Coffin Corner.
"The coffin corner or Q-Corner is the altitude at or near which an aircraft's stall speed is equal to the critical Mach number, at a given gross weight and G loading. At this altitude the aircraft becomes nearly impossible to keep in stable flight. Since the stall speed is the minimum speed required to maintain level flight, any reduction in speed will cause the airplane to stall and lose altitude. Since the critical Mach number is maximum speed at which air can travel over the wings without losing lift due to flow separation and shock waves, any increase in speed will cause the airplane to lose lift, or to pitch heavily nose-down, and lose altitude. The "corner" refers to the triangular shape at the top of a flight envelope chart where the stall speed and critical Mach number lines come together."
Consequences.
"When an aircraft slows to below its stall speed (or more properly, when the wing exceeds its critical angle of attack), the airflow over the top of the wing separates from the wing surface, and lift decreases dramatically (the wing "stalls"). Because the lift reduces while the aircraft's weight does not, the aircraft loses altitude. When the aircraft exceeds its critical Mach number, then drag increases or Mach tuck occurs, which can cause the aircraft to upset, lose control, and lose altitude. In either case, as the airplane falls, it could gain speed and then structural failure could occur.
As an aircraft approaches its coffin corner, the margin between stall speed and critical Mach number becomes smaller and smaller. Small changes could put one wing or the other above or below the limits. For instance, a turn causes the inner wing to have a lower airspeed, and the outer wing, a higher airspeed. The aircraft could exceed both limits at once. Or, turbulence could cause the airspeed to change suddenly, to beyond the limits."
Matt, I read it too.
But those airframes are quite strong. We've all seen the video's of wings being stressed to the breaking point. I cannot imagine anyone certifying (or insuring) the aircraft if it busts up during a stall.
Remember, we are not talking normal 3 g stresses which most airlines are certified to. FAR Part 25 gives Specific requirements that are the minimum requirements and it is expected that for the most part commercial aircraft will be operated within the envelope established. What happened to this aircraft seems to be abnormal. We'll see as more more data is collected.Matt, I read it too.
But those airframes are quite strong. We've all seen the video's of wings being stressed to the breaking point. I cannot imagine anyone certifying (or insuring) the aircraft if it busts up during a stall.
Aint the Airbus designed to stall nice?
Gentle nose drop? Not exactly 9g. And isn't the FBW to stop overstress? More questions.....
More I know is the less I know in this crash as things contradict....
If the aircraft had pitot issues then the pilots would have had plenty time to radio and the aircraft would not fall apart because of this....
My view is that either went into the storm to slow and stalled but surely it would recover? Or it was attempted recovery and high speed close to sound and it couldn't take it and fell apart? But the FBW would have done a safe pull out....
Or it lost all electrics but why would it do that?...
Only the black boxes will tell...
Matt, I read it too.
But those airframes are quite strong. We've all seen the video's of wings being stressed to the breaking point. I cannot imagine anyone certifying (or insuring) the aircraft if it busts up during a stall.