Originally Posted by
mseyfang
@OldBoeingDriver Unlikely in my opinion overspeed alone would cause disintegration. United 175 hit the WTC at 513 knots at 700 feet and remained intact until impact, which is past the barber pole. Vmo for that airplane is 360 knots IIRC. Overspeed plus some kind of abrupt maneuver, possibly.
You have to take into consideration that Mmo is potentially more critical than Vmo. Exceeding Vmo alone is empirically not that dangerous.
Significantly exceeding Mmo on the other hand can lead to nasty flutter which can then lead to disintegration.
At high altidute you would hit ciritcal Mach number prior to hitting any ciritcal airspeed. Theoretically this can become unrecoverable due to Mach Tuck. But to get to that point will required a significant and extended dive since drag will start to increase heavily when approaching Mach 1.
That said, a straight steep dive from 35k probably could lead to disintegration.
In reality straight dives are rare and less disorienting. More often a spiral dive ensues.
And that also tends to be more dangerous and also more difficult to identify and counter correctly at night or in IMC.
At lower altitudes it is therefore rather this 'graveyard spiral' mechanism that sometimes leads to in-flight disintegration (especially of GA aircraft that are otherwsie rather difficult to break up in flight). In that case a spiral dive which is not actively countered continues to accelerate in rotation and vertical speed. Due to longitudinal stability the aircraft will pull more and more g to counter the increasing speed. If not interrupted quickly by dedicated and correct action this will lead quickly to self- disintegration. Instinctive pull-up prior to complete arrest of rotation aggravates the problem and will lead to immediate disintegration.