Flt 587-Airbus vs American Airlines

http://www.nytimes.com/2004/03/21/nyregion/21plane.html is a report of
the maneuvering by both Airbus and American Airlines to get in their 2
cents, pilot training vs inadequate design, in the crash of AA Flt 587
over Queens. Apparently the tail came off because of a violent yaw
type of pilot induced oscillation. The range of rudder control
available to the pilot seems grossly inadequate. AA may have
contributed to the problem by failing to reflect the design flaw in
their training, however their real failure might be not grounding the
planes for suicidal instability. Pilots of the F86D had to accept
working around a low altitude-high speed pilot induced oscillation. In
that case the oscillations were in pitch. I could accept such on a
military fighter plane, but such an accident waiting to happen in a
commercial airliner seems unconscionable.


John Bailey
http://home.rochester.rr.com/jbxroads/mailto.html

"John Bailey" wrote in message
...
http://www.nytimes.com/2004/03/21/nyregion/21plane.html is a report of
the maneuvering by both Airbus and American Airlines to get in their 2
cents, pilot training vs inadequate design, in the crash of AA Flt 587
over Queens. Apparently the tail came off because of a violent yaw
type of pilot induced oscillation. The range of rudder control
available to the pilot seems grossly inadequate.

The pilot's excess command authority over the rudder control system is why
the structure delaminated.

AA may have
contributed to the problem by failing to reflect the design flaw in
their training, however their real failure might be not grounding the
planes for suicidal instability.

I'll leave this the Schmidt to answer.

Pilots of the F86D had to accept
working around a low altitude-high speed pilot induced oscillation. In
that case the oscillations were in pitch. I could accept such on a
military fighter plane, but such an accident waiting to happen in a
commercial airliner seems unconscionable.

The airplane experianced a rudder stall (rudder reversal) due to turbulent
air flow; which was probably a direct result of ATC loss of seperation.
There is a USAir flight 427 suspected of having crashed for the same reason.
It is quite possible that training pilots to use excessive rudder and
operator panic are the cause of these crashes; excepting the abnormal
operating conditions.

"John Bailey" wrote
http://www.nytimes.com/2004/03/21/nyregion/21plane.html is a report of
the maneuvering by both Airbus and American Airlines to get in their 2
cents, pilot training vs inadequate design, in the crash of AA Flt 587
over Queens. Apparently the tail came off because of a violent yaw
type of pilot induced oscillation. The range of rudder control
available to the pilot seems grossly inadequate. AA may have
contributed to the problem by failing to reflect the design flaw in
their training, however their real failure might be not grounding the
planes for suicidal instability. Pilots of the F86D had to accept
working around a low altitude-high speed pilot induced oscillation. In
that case the oscillations were in pitch. I could accept such on a
military fighter plane, but such an accident waiting to happen in a
commercial airliner seems unconscionable.

My impression from reading the AvWeek reports is that this problem isn't
unique to A300s nor to Airbus products. The fin can be overloaded in most
transports if opposite rudder is commanded while a significant yaw has
occurred. I'm not a pilot but AvWeek claimed that standard recovery training
for transport pilots could lead to this condition.

After an exhausting session with Victoria's Secret Police, "Paul F
Austin" confessed the following:

My impression from reading the AvWeek reports is that this problem isn't
unique to A300s nor to Airbus products. The fin can be overloaded in most
transports if opposite rudder is commanded while a significant yaw has
occurred. I'm not a pilot but AvWeek claimed that standard recovery training
for transport pilots could lead to this condition.

You are correct, I fly the 757 and we've recently had some expanded
warning verbiage added to our flight manual about excessive rudder
inputs during an engine failure. Pretty soon after that AA crash we
were cautioned about excessive rudder inputs.

Why is rudder input mandatory during an engine failure vice simply
using ailerons?

Quick example, a United 747-400 lost an engine on takeoff from SFO a
couple years back. The jet was full/heavy, the FO (guy in the right
seat) was making the takeoff. During intial climbout, the FO used full
aileron/yoke to maintain wings level while trying to climb straight
out. The only problem was the drag caused by the deployed spoilers
(for roll) on the side with two good motors. [picture aileron into the
two good engines trying to "lift" the wing with only one motor to turn
into the good side]. This was not the approved solution for
controlling a 747 on takeoff with an engine failure.

As a result the drag severely degraded the climb capability and there
was a ridge line in front of the jet. Two guys sitting in jumpseats
finally had enough of the FO's hamfisted technique and started
insisting he use rudder to control the yaw and not aileron. The FO
listened..."Oh yeah, ****, f*ck me..." and they cleared the rapidly
rising terrain by mere feet.

So that is why rudder input is critical, minimize yaw and drag to
provide climb performance.

And as you alluded to, blind rapid full rudder inputs can simply
over-G the airframe.

The technique we are taught during an engine failure is to climb
straight ahead (airspace and terrain permitting), engine failure
during the takeoff roll are pretty painless if you simply blend in
enough rudder to keep on centerline as you accelerate then shift to
instruments once airborne.

Engine failure during climbout while in a turn can be disorienting
with the greater yawing and rolling tendencies due to higher speeds
and power settings...obviously greater care must be taken by the pilot
flying the jet.

Juvat

"Robey Price" wrote
After an exhausting session with Victoria's Secret Police, "Paul F
Austin" confessed the following:

My impression from reading the AvWeek reports is that this problem isn't
unique to A300s nor to Airbus products. The fin can be overloaded in most
transports if opposite rudder is commanded while a significant yaw has
occurred. I'm not a pilot but AvWeek claimed that standard recovery
training
for transport pilots could lead to this condition.

You are correct, I fly the 757 and we've recently had some expanded
warning verbiage added to our flight manual about excessive rudder
inputs during an engine failure. Pretty soon after that AA crash we
were cautioned about excessive rudder inputs.

Why is rudder input mandatory during an engine failure vice simply
using ailerons?

Quick example, a United 747-400 lost an engine on takeoff from SFO a
couple years back. The jet was full/heavy, the FO (guy in the right
seat) was making the takeoff. During intial climbout, the FO used full
aileron/yoke to maintain wings level while trying to climb straight
out. The only problem was the drag caused by the deployed spoilers
(for roll) on the side with two good motors. [picture aileron into the
two good engines trying to "lift" the wing with only one motor to turn
into the good side]. This was not the approved solution for
controlling a 747 on takeoff with an engine failure.

As a result the drag severely degraded the climb capability and there
was a ridge line in front of the jet. Two guys sitting in jumpseats
finally had enough of the FO's hamfisted technique and started
insisting he use rudder to control the yaw and not aileron. The FO
listened..."Oh yeah, ****, f*ck me..." and they cleared the rapidly
rising terrain by mere feet.

So that is why rudder input is critical, minimize yaw and drag to
provide climb performance.

And as you alluded to, blind rapid full rudder inputs can simply
over-G the airframe.

The technique we are taught during an engine failure is to climb
straight ahead (airspace and terrain permitting), engine failure
during the takeoff roll are pretty painless if you simply blend in
enough rudder to keep on centerline as you accelerate then shift to
instruments once airborne.

Engine failure during climbout while in a turn can be disorienting
with the greater yawing and rolling tendencies due to higher speeds
and power settings...obviously greater care must be taken by the pilot
flying the jet.

Thanks for the information. I am somewhat amazed that the FAA doesn't
require load analysis of the fin under yaw/extreme opposite rudder but
(again according to AvWeek), it does not.

In article ,
"Paul F Austin" wrote:

"Robey Price" wrote
After an exhausting session with Victoria's Secret Police, "Paul F
Austin" confessed the following:

My impression from reading the AvWeek reports is that this problem isn't
unique to A300s nor to Airbus products. The fin can be overloaded in most
transports if opposite rudder is commanded while a significant yaw has
occurred. I'm not a pilot but AvWeek claimed that standard recovery
training
for transport pilots could lead to this condition.

You are correct, I fly the 757 and we've recently had some expanded
warning verbiage added to our flight manual about excessive rudder
inputs during an engine failure. Pretty soon after that AA crash we
were cautioned about excessive rudder inputs.

Why is rudder input mandatory during an engine failure vice simply
using ailerons?

Quick example, a United 747-400 lost an engine on takeoff from SFO a
couple years back. The jet was full/heavy, the FO (guy in the right
seat) was making the takeoff. During intial climbout, the FO used full
aileron/yoke to maintain wings level while trying to climb straight
out. The only problem was the drag caused by the deployed spoilers
(for roll) on the side with two good motors. [picture aileron into the
two good engines trying to "lift" the wing with only one motor to turn
into the good side]. This was not the approved solution for
controlling a 747 on takeoff with an engine failure.

As a result the drag severely degraded the climb capability and there
was a ridge line in front of the jet. Two guys sitting in jumpseats
finally had enough of the FO's hamfisted technique and started
insisting he use rudder to control the yaw and not aileron. The FO
listened..."Oh yeah, ****, f*ck me..." and they cleared the rapidly
rising terrain by mere feet.

So that is why rudder input is critical, minimize yaw and drag to
provide climb performance.

And as you alluded to, blind rapid full rudder inputs can simply
over-G the airframe.

The technique we are taught during an engine failure is to climb
straight ahead (airspace and terrain permitting), engine failure
during the takeoff roll are pretty painless if you simply blend in
enough rudder to keep on centerline as you accelerate then shift to
instruments once airborne.

Engine failure during climbout while in a turn can be disorienting
with the greater yawing and rolling tendencies due to higher speeds
and power settings...obviously greater care must be taken by the pilot
flying the jet.

Thanks for the information. I am somewhat amazed that the FAA doesn't
require load analysis of the fin under yaw/extreme opposite rudder but
(again according to AvWeek), it does not.



Political and un-Diplomatic pressure from the foreign states heavily
invested in the sucess of Airbus.

--
Ron

On Sun, 21 Mar 2004 22:36:45 GMT, (John
Bailey) wrote:

http://www.nytimes.com/2004/03/21/nyregion/21plane.html is a report of
the maneuvering by both Airbus and American Airlines to get in their 2
cents, pilot training vs inadequate design, in the crash of AA Flt 587
over Queens.

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. This inadequacy is described in
the Times article.
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)

I could accept such (lurking instability) on a
military fighter plane, but such an accident waiting to happen in a
commercial airliner seems unconscionable.

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. In the F86D at high speed, low altitude, the human simply
could not control the pitch of the plane, once it began oscillating.
The recourse was to let the plane fly out of the situation and hope it
was pointed in the right direction when it emerged. Many hot pilots
were red faced after insisting it was the pilots fault and then
finding themselves unable to avoid the maneuver. 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.

John Bailey
http://home.rochester.rr.com/jbxroads/mailto.html

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.

Political and un-Diplomatic pressure from the foreign states heavily
invested in the sucess of Airbus.



The same for Boeing 737 tail problem... resolved for the entire fleet
only in ....2012....