A Q on horizontal turns

During a cruise, just pressing on one of the rudders should make an
aircraft turn horizontally in that direction, when no ailerons are
used. Reducing power in the opposite engine should logically accelerate
such a turn.

Makes me wonder why then was it that, in the crash at the end of 2001
just outside of NY, the A300's rear bulkhead came loose when the pilot
used the rudder to correct a yaw induced by probably a wake vortex ?
Ramapriya

"Ramapriya" wrote

Makes me wonder why then was it that, in the crash at the end of 2001
just outside of NY, the A300's rear bulkhead came loose when the pilot
used the rudder to correct a yaw induced by probably a wake vortex ?
Ramapriya


Google for that discussion, but in short, the rudder was used rapidly going
from full deflection, to other side full deflection. The plane was not
designed for that, and it failed. Part of the fault seems to lie with the
airline, for not properly training its pilots.
--
Jim in NC

Morgans wrote:

Google for that discussion, but in short, the rudder was used rapidly
going
from full deflection, to other side full deflection. The plane was
not
designed for that, and it failed. Part of the fault seems to lie
with the
airline, for not properly training its pilots.
--
Jim in NC

No Jim, I actually know that report, and the statements of both the
airline and Airbus too. The surprise is in knowing that such action,
which I think is natural, isn't automatically built into in the design
of an aircraft. Why do you think that's so? Aren't such boat-turns
normal? Should be, isn't it?

Ramapriya

"Ramapriya" wrote:
No Jim, I actually know that report, and the statements of both the
airline and Airbus too. The surprise is in knowing that such action,
which I think is natural,

Rapid, opposite deflections of the rudder are not "natural,"
particularly in a jet transport aircraft.

isn't automatically built into in the design
of an aircraft. Why do you think that's so?

Because designers cannot allow for every conceivable misuse of the
equipment.

Aren't such boat-turns
normal?

Not in that kind of airplane--besides, he wasn't just making a rudder
turn, he was wagging the rudder back and forth.

Should be, isn't it?

Not necessarily. Airplanes are designed for performance that meets a
particular mission. Airliners are not the same as aerobatic aircraft,
for instance.
--
Dan
C172RG at BFM

"Ramapriya" wrote in message
oups.com...


No Jim, I actually know that report, and the statements of both the
airline and Airbus too. The surprise is in knowing that such action,
which I think is natural, isn't automatically built into in the design
of an aircraft. Why do you think that's so? Aren't such boat-turns
normal? Should be, isn't it?

Ramapriya


Turns in aircraft are most often intended to be what is called
"coordinated." That is the ailerons and rudder are used in conjunction so
that there are *no* purely horizontal forces felt by the passengers. In
airline and corporate flying this is sometimes called "not making the ice
cubes clink." You try to maneuver the aircraft so that the passengers, and
their drinks, are not disturbed.

Making these boat turns would be like filling a station-wagon automobile
with children, accelerating to highway speeds, and then making an abrupt
turn of the steering wheel. The children wuld go sliding all over the car's
cabin.



--

Scott

tscottme wrote:

Making these boat turns would be like filling a station-wagon
automobile
with children, accelerating to highway speeds, and then making an
abrupt
turn of the steering wheel. The children wuld go sliding all over
the car's
cabin.

Scott,
Not having been in an aircraft boat-turn before, I find your example a
wee addling. The kids would get hurled across the seats because the
station wagon is trying to turn horizontally about its axis while being
restricted in its lateral movement by the tires that are grounded. In
an aircraft, there's just thin air outside, so I'd presume it'll mildly
keep sliding sidewards too (in the opposite direction) while turning
about its axis. It might just feel like in a briskish whirligig.
Or does it?

Ramapriya
ayirpamar@gmail

Ramapriya wrote:

In
an aircraft, there's just thin air outside, so I'd presume it'll mildly
keep sliding sidewards too (in the opposite direction) while turning
about its axis. It might just feel like in a briskish whirligig.

I've never been in a briskish whirligig, so I don't know, but, when you make a
rudder turn, momentum attempts to have the contents continue in a straight line.
In some areas of a large aircraft, unsecured cargo would slide sideways in such
a turn. In a coordinated turn, the forces of momentum and gravity balance out.

As far as passengers are concerned, uncoordinated maneuvers tend to make them
nauseous. This effect is stronger the further away from the center of the wing
they sit.

George Patterson
The desire for safety stands against every great and noble enterprise.

"Ramapriya" wrote in message
oups.com...
Not having been in an aircraft boat-turn before, I find your example a
wee addling. The kids would get hurled across the seats because the
station wagon is trying to turn horizontally about its axis while being
restricted in its lateral movement by the tires that are grounded. In
an aircraft, there's just thin air outside, so I'd presume it'll mildly
keep sliding sidewards too (in the opposite direction) while turning
about its axis.

It's a little of both. It won't be as bad as the aforementioned station
wagon, because the rudder isn't capable of producing as much of a turn. In
fact, this is why it's so important to use aileron to bank the plane too for
a turn. But a turn does still happen to a lesser degree, and the passengers
would still feel the apparent force pushing them to the outside of the turn.

Pete

"Morgans" wrote in message
...

"Ramapriya" wrote

Makes me wonder why then was it that, in the crash at the end of 2001
just outside of NY, the A300's rear bulkhead came loose when the pilot
used the rudder to correct a yaw induced by probably a wake vortex ?
Ramapriya


Google for that discussion, but in short, the rudder was used rapidly
going
from full deflection, to other side full deflection. The plane was not
designed for that, and it failed. Part of the fault seems to lie with the
airline, for not properly training its pilots.
--
Jim in NC



And there are many people that fault Airbus for not making this "design
feature" known more widely. I remember reading in Aviation Week shortly
after the crash that Airbus didn't make much effort to notify customers that
full deflection of the rudder could cause a catstrophic accident because
they decided nobody would want to apply full-deflection as it would be
dangerous.

--

Scott

tscottme wrote:

And there are many people that fault Airbus for not making this "design
feature" known more widely.

Actually, they did. There was that letter which Airbus, Boeing and the
FAA (yes, all three, together, in one letter!) wrote to the operator
pointing out exactly this and asking for a change in pilot training. But
of course, "many people" in the USA welcome any rumour which could be
used against Airbus.

Stefan