Flt 587-Airbus vs American Airlines

After an exhausting session with Victoria's Secret Police, John
Bailey confessed the following:

Remarks in response to the original post assume the actual failu
the rudder failing catastrophically, was due to the pilot responding
in an excessive way to a situation in which yaw needed to be
controlled. These resonses do not mention the fact that the yaw
needing to be controlled AND the excessive response came from a
characteristic of the plane itself.

Good point.

In addition, rudder application does not move
the plane instantly, and the delay might encourage a pilot to keep
applying the rudder until the aircraft moved further than the pilot
intended, according to Mr. Hess's analysis. The natural reaction would
then be to apply the rudder in the opposite direction. (end quote)

I've witnessed yaw PIO during V(one) cuts in the MD-80 and 757
simulator, it can happen with any jet IMO in a high pucker factor
situation...was never a problem in the F-16 8-)

Pilot induced oscillation is the result of a failure of the controls
design to take into account the inherent lag of the human control
response.

Which is addressed in the F-16 with Standby Gains when the gear is
down or the refueling door is open. Would have been nice for the F-4
when refueling at a heavy weight and high altitude (above about
FL270).

Apparently the most notorious case occured when the
squadron commander at Selfridge AFB, lead a flyby formation,
reaching levels of oscillation that had his wingtips generating vortex fog

Ya know you don't have to be doing anything special to generate
visible wingtip vortices. See them all the time in high relative humid
conditions from jets stabilized on final approach...but I get your
point.

The worst case I've heard of was an airshow flyby of RoKAF F-4s.
Number 3 trying to be perfect as Sq CO Lead approaches the sight line
at a very high speed (running late IIRC) gets into vicious PIO and
finally "freezes" the stick aft as his jet zooms out of formation for
an unscheduled missing man demo (much better than a fireball sliding
down the runway).

Juvat

"John Bailey" wrote in message
...

Here is the key quote:
(quote)
But the author of the study, Ronald A. Hess of the University of
California, said that the design of the rudder was conducive to such
oscillations. One problem, he found, was that on the A-300, the amount
of force needed to start moving the rudder was relatively high, and
the total range of motion allowed at that speed was only a little over
an inch, making it very difficult to apply any amount of rudder less
than its full extension. In addition, rudder application does not move
the plane instantly, and the delay might encourage a pilot to keep
applying the rudder until the aircraft moved further than the pilot
intended, according to Mr. Hess's analysis. The natural reaction would
then be to apply the rudder in the opposite direction. (end quote)

More likely Hess is full of **** and should look further into the
circumstances of the crash.

"Tarver Engineering" wrote in message ...
"John Bailey" wrote in message
...
SNIP:
One problem, he found, was that on the A-300, the amount
of force needed to start moving the rudder was relatively high, and
the total range of motion allowed at that speed was only a little over
an inch, making it very difficult to apply any amount of rudder less
than its full extension.
SNIP:
Is he trying to say that operational reasons limit rudder motion to a
little over an inch, or what? Doesn't sound like enough to handle one
engine out with the other one firewalled to, say, climb out of San
Juan, Costa Rico.
Walt BJ

"WaltBJ" wrote in message
om...
"Tarver Engineering" wrote in message
...
"John Bailey" wrote in message
...
SNIP:
One problem, he found, was that on the A-300, the amount
of force needed to start moving the rudder was relatively high, and
the total range of motion allowed at that speed was only a little over
an inch, making it very difficult to apply any amount of rudder less
than its full extension.
SNIP:
Is he trying to say that operational reasons limit rudder motion to a
little over an inch, or what? Doesn't sound like enough to handle one
engine out with the other one firewalled to, say, climb out of San
Juan, Costa Rico.

I'll agree with Walt's observation that the poster may wish to rethink their
contribution to the thread. Get a clue, FAA has two zeros.