Creative Speculation

Seger quotes - "It is noteworthy that the section of Part 23 regarding flutter, 23.629, makes no mention of altitude. "

FAR part 23 is for small aircraft, like a Cessna 172... doh!

Now read reality....

"Many years ago, before oscilloscopes and sensitive vibration measuring devices were commonly used, aerodynamicists had a very basic means of identifying an airline's flutter speed. They'd find a skilled test pilot, show him a wheelbarrow full of money, then send him aloft to dive the airplane at dazzling airspeeds. The test pilot's job was to determine the speed at which the airplane experiences flutter.


When he returned-and when his breathing slowed and he regained his ability to speak-he'd tell his tale. He'd inform the engineers about the speed beyond which the airplane experienced flutter. This speed is known as Vd or design dive speed. "

http://flighttraining.aopa.org/magazine/1998/May/199805_Operating_Within_the_Envelope_Part_1.html

Now watch the flight certification test being done on the A380. Notice the pilots visibly shaking in their seats... note the airplane broke prior to Vd/Md, the test had to be aborted, and the airplane had to be modified to reach Vd/Md.

http://theflyingengineer.com/tag/vdmd/

There is no 50% margin of safety factored above Vd. You are confusing limit load with speed. The 50% margin of Safety is for G loading only.

"§25.303 Factor of safety.

Unless otherwise specified, a factor of safety of 1.5 must be applied to the prescribed limit load which are considered external loads on the structure. When a loading condition is prescribed in terms of ultimate loads, a factor of safety need not be applied unless otherwise specified. "

http://www.ecfr.gov/cgi-bin/text-idx?SID=1aca5418517b105598535f0eaa929f65&node=14:1.0.1.3.11.3.162.2&rgn=div8

The margin of safety for speed is between Vc (of which Vmo is derived) and Vd ...

§25.1505 Maximum operating limit speed.
The maximum operating limit speed (VMO/MMO airspeed or Mach Number, whichever is critical at a particular altitude) is a speed that may not be deliberately exceeded in any regime of flight (climb, cruise, or descent), unless a higher speed is authorized for flight test or pilot training operations. VMO/MMO must be established so that it is not greater than the design cruising speed VC and so that it is sufficiently below VD/MD or VDF/MDF, to make it highly improbable that the latter speeds will be inadvertently exceeded in operations. The speed margin between VMO/MMO and VD/MD or VDFM/DF may not be less than that determined under §25.335(b) or found necessary during the flight tests conducted under §25.253.
http://www.ecfr.gov/cgi-bin/text-idx?SID=1aca5418517b105598535f0eaa929f65&node=14:1.0.1.3.11.7.198.3&rgn=div8

Vd is the end of the Flight Maneuvering Envelope and the start of the structural failure zone/structural limit,

[img][/img]
http://www.ecfr.gov/cgi-bin/text-idx?SID=1aca5418517b105598535f0eaa929f65&node=14:1.0.1.3.11.3.164.7&rgn=div8

.... and it is proven by precedent.

[img][/img]

You really should watch the film, maybe you'll actually learn something. Such as, we do not claim an aircraft breaks at 1 knot over Vd, Mr Strawman.....