[usafsk]

Airspeed had little to do with it. The forces exerted on the aircraft in the 587 case had to do with sideslip forces more than 2X the design limits on the vertical stabilizer. The first officer had at least two previous incidents of overzealous response to wake turbulence.

In the 587 incident, during the first, minor bump from the 747 wake, he moved the control wheel of the aircraft more than 30 degrees in each direction. This type of action, considering the amount of wake encountered, was dangerous and excessive.

In response to the second encounter, a few seconds later in the flight, he executed 5 cyclic rudder pedal inputs. That's nuts. He snapped the tail off.

If you want aircraft that would not snap the tail off under those circumstances, you'll need to be willing to spend about 100x what you currently pay for a ticket. I was watching A-10 straffing runs at an ANG range in Michigan when a pilot snapped both wings off coming out of a run too aggressively. Physics are physics.

[spanalot]

"had to do with sideslip forces more than 2X the design limits on the vertical stabilizer. "

Say what?

Since when do side slip forces come anywhere near the airspeed forces that the rudder always encounters.

And if so, why was it that only the rudder failed?

And re: the "5 cyclic rudder inputs" that were nuts, what about cyclic air forces that occur naturally in normal harmonic buffeting?

[bill1952]

Michigan when a pilot snapped both wings off coming out of a run too aggressively. Physics are physics.

He must have been WAY beyond the max manuevering speed.

[monkeyshine]

I had read that the airbus flight control system is designed to prevent exactly this. The pilot is overridden when he moves the control more than 30 degrees in any direction. This could be dangerous, esp if you somehow veer off course and need to go over, say, a mountain. Yes, you could rip the wings off trying to get up over it, but flying into the mountain has a certain inevitable outcome but in trying to avoid it the wings might not rip off.

I think the airbus needs to add a pilot override button that will override the computer pilot override for extreme situations where making a hard manuever is absolutely critical. As far as I know, the Boeing do not have such a pilot override function.

Further, I read that this pilot-override feature is put in place because of the design of the craft itself. It cannot handle stress as well as a Boeing and thus, the restrictions are put in place. Not sure how accurate this info is, but it's what I read on a airplane blog a couple weeks ago.

[DuncanWaring]

For certification of the "Business Jet" aircraft, the flight test requires passing a "Double Rudder Kick Test". This involves deflecting the rudder in one direction as hard as the test pilot can, then quickly kicking it as far as possible in the other direction, then back hard in the original direction.

Wearing of parachutes is not unheard-of.

I don't think the large passenger-category aircraft (FAR Part 121? 135?) have to pass such a test, but at only 240 knots the rudder should "stall" before the pilot can kick it hard enough to snap it off.