Is VMO an absolute aerodynamic limit ?
Why don't jets have VNE ?
Previously under CARs all jets had published VMO and VNE figures for example:
Type: VMO / VNE (kts)
B747-200: 375 / 445
DC-8-73: 352 / 406
DC-9-30: 350 / 425
DC-10-30: 356 / 400
The B757-200 however has a VMO below 10,000 ft of just 250 knots because the windshield isn't certified to withstand birdstrike above 313 knots. Above 10,000 ft the 757 is VMO limited to 350 knots.
The son of Bill Lear, John lear and I are debating the point in relation to his 9/11 conspiracy theories. 9/11 conspiracists maintain that novice pilots could not have flown a 757 into the Pentagon because it was VMO limited and thus the dive at 350 knots was not achievable as it exceeded VMO.
I say this is balderdash. The VMO limit is a windscreen issue only. John Lear maintains that VMO is an absolute aerodynamic limit on the airframe above which flutter would prevent novice pilots performing the manouveres.
I say it is not an absolute speed limit. I say there is a higher limit VNE at which, then loss of control is possible. Trouble is FAR Part 25 no longer requires demonstration of VNE.
John Lear and I have also crossed swords over United 175 which flew into WTC2 at 466 knots (according to radar tape analysis). John Lear maintains a novice pilot could not have done this.
In fact I am not quite sure what John Lear is saying because in some instances he seems to suggest that the 767 could not have flown at that speed at all because it exceeds the 767 VMO (which Lear says is impossible).
At other times he simply says the hijackers lacked the skill to do so. (case of conveniently shifting the goalposts).
Comments ?