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gcrowder2
Joined: 09 Jan 2006
Posts: 136
Location: Golden, Colorado USA
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 Posted: Fri Jul 28, 2006 8:50 am Post subject: Cross controlling ailerons and rudder in the landing approac |
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Hey Bob!
I am shocked and saddened by Cliff and Bettys accident at Oshkosh. This
should not
have happened to a pair who had been so helpful and friendly to others in
the flying
community.
It seems that there is some misunderstanding how a "cross controlled"
situation can
occur.
The classic cross controlled scenario is when the pilot overshoots the
base to final turn being
blown downwind using heavy ailerons and rudder to correct the overshoot up
to the point the plane is headed back to the runway and then the pilot uses
rapid opposite aileron to level the wings. The downgoing aileron on the
upwind side is asked to generate a lot more lift when the airspeed is very
slow, causing the upwind wing to stall precipitating a low altitude spin.
I was taught on the Europa to never use the bottom rudder on the turn from
base to final and just make the turn with ailerons. If you hit the bottom
rudder, you are slowing the inside wing more than the outside wing. It is
permissible to use the top rudder in the turn as this accelerates the inside
wing (which is what you do in a slip). So one can cause a stall by using
bottom rudder and not be cross controlled. I was taught that as long as you
use top rudder only (or no rudder at all) on the base to final turn, the
inside wing cannot stall first. Once lined up on final, I then start using
the rudder to maintain directional allignment with the runway. If I can't
make the turn just using the ailerons, I have screwed up and will do a go
around! The whole idea is that as long as
the aircraft stays coordinated, the wing will only stall straight ahead,
still not a good thing, but
possibly recoverable where a spin entry is not.
Glenn
| Quote: | From: "Bob Jacobsen" <jacobsenra(at)hotmail.com>
Reply-To: europa-list(at)matronics.com
To: europa-list(at)matronics.com
Subject: Europa Oshkosh Accident
Date: Fri, 28 Jul 2006 07:55:00 -0700
I have additional information on Cliff & Betty's Oshkosh accident. First
is the NTSB's preliminay report - this can also be found on the NTSB
website.
Also the NTSB has spoken with Mike and a pilot we know who was an
eyewitness. Additionally I test flew Cliff's plane for him, knew him well
and knew what kind of pilot he was. My hope is this information will
prevent another accident of this type.
First the NTSB Report:
NTSB Identification: CHI06FA196
14 CFR Part 91: General Aviation
Accident occurred Sunday, July 23, 2006 in Oshkosh, WI
Aircraft: Shaw Europa XS, registration: N229WC
Injuries: 2 Fatal.
This is preliminary information, subject to change, and may contain errors.
Any errors in this report will be corrected when the final report has been
completed.
On July 23, 2006, at 0845 central dylight time, a Shaw Europa XS, N229WC,
collided with the runway following a loss of control while on final
approach to runway 27 (6,178 feet by 150 feet, dry asphalt) at the Wittman
Regional Airport (OSH), Oshkosh, Wisconsin. The private pilot and passenger
were fatally injured. The airplane was destroyed. The 14 Code of Federal
Regulations Part 91 personal flight was operating in visual meteorological
conditions without a flight plan. The flight originated from the Portage
Municipal Airport (C47), Portage, Wisconsin, at approximately 0815.
The airplane was landing at OSH for the EAA AirVenture fly-in. Witness
reported seeing the airplane "low and slow" on downwind to runway 27. One
witness, a certified flight instructor, stated the airplane remained slow
as it overshot final approach. The witnesses reported seeing the airplane
stall on final approach. The airplane impacted the runway on the displaced
threshold.
Now information about Cliff's plane.
I test flew the plane for the first time on 6/29/03 - Flight lasted about a
half hour. I did some slow flight to get airspeed readings but did not
fully stall the airplane. I felt that it would drop a wing - so I was very
careful to keep everything centered. About a week later John Hurst was
flying the plane with Cliff to try to iron out an engine problem. They
stalled the plane and it flipped inverted instantly. We added some stall
strips and got it's behavior a bit better - but it was a always a nasty
stalling airplane.
final. I am sure he pulled a hard turn to final while slow. I can also
guess he was a bit cross controlled and the plane stalled. snapped inverted
and went into a spin. I am told the plane impacted nose down and inverted.
I am also told it had spun "a couple of times".
The Europa is a great design however it does have a very powerful and
sensitive elevator (thats why is so fun). Additionally the rudder is
powerful - but must be used correctly. Cross controlling and accelerated
stalling any airplane is a problem, the Europa is even more so than some
and probably easier to do with the powerful controls.
Here is waht the FAA pilots flying handbook says about this:
According to the FAA publication Airplane Flying Handbook, section on
accelerated stalls and cross control stalls, ...Stalls which result from
abrupt maneuvers tend to be more rapid, or severe, than the unaccelerated
stalls, and because they occur at higher-than-normal airspeeds, they may be
unexpected by an inexperienced pilot. Failure to take immediate steps
toward recovery when an accelerated stall occurs may result in a complete
loss of flight control, notably, power-on spins... a cross control
stall...is most apt to occur during a poorly planned and executed
base-to-final approach turn...the airplane often stalls with little
warning. The nose may pitch down, the inside wing may suddenly drop and the
airplane may continue to roll to an inverted position...It is imperative
that this type of stall not occur during an actual approach to a landing
since recovery may be impossible prior to ground contact due to the low
altitude...."
Bob Jacobsen
http://www.matronics.com/Navigator?Europa-List
http://wiki.matronics.com
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fklein(at)orcasonline.com
Guest
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| Posted: Fri Jul 28, 2006 9:46 am Post subject: Cross controlling ailerons and rudder in the landing approac |
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Glenn,
I have never heard the terms, "bottom rudder", or "top rudder". At the
risk of asking a stupid question, could you please explain the terms
and how they apply in the present instance.
Fred
On Friday, July 28, 2006, at 09:48 AM, GLENN CROWDER wrote:
| Quote: |
I was taught on the Europa to never use the bottom rudder on the turn
from base to final and just make the turn with ailerons. If you hit
the bottom rudder, you are slowing the inside wing more than the
outside wing. It is permissible to use the top rudder in the turn as
this accelerates the inside wing (which is what you do in a slip). So
one can cause a stall by using bottom rudder and not be cross
controlled. I was taught that as long as you use top rudder only (or
no rudder at all) on the base to final turn, the inside wing cannot
stall first.
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gcrowder2
Joined: 09 Jan 2006
Posts: 136
Location: Golden, Colorado USA
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| Posted: Fri Jul 28, 2006 10:04 am Post subject: Cross controlling ailerons and rudder in the landing approac |
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Hey Fred!
Bottom rudder would be the lower rudder pedal in a turn. On a left turn
to final,
the left rudder would be the bottom rudder.
Glenn
| Quote: | From: Fred Klein <fklein(at)orcasonline.com>
Reply-To: europa-list(at)matronics.com
To: europa-list(at)matronics.com
Subject: Re: Cross controlling ailerons and rudder in the
landing approach
Date: Fri, 28 Jul 2006 10:43:51 -0700
Glenn,
I have never heard the terms, "bottom rudder", or "top rudder". At the risk
of asking a stupid question, could you please explain the terms and how
they apply in the present instance.
Fred
On Friday, July 28, 2006, at 09:48 AM, GLENN CROWDER wrote:
>
> I was taught on the Europa to never use the bottom rudder on the turn
>from base to final and just make the turn with ailerons. If you hit the
>bottom rudder, you are slowing the inside wing more than the outside wing.
> It is permissible to use the top rudder in the turn as this accelerates
>the inside wing (which is what you do in a slip). So one can cause a
>stall by using bottom rudder and not be cross controlled. I was taught
>that as long as you use top rudder only (or no rudder at all) on the base
>to final turn, the inside wing cannot stall first.
http://www.matronics.com/Navigator?Europa-List
http://wiki.matronics.com
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rparigor(at)suffolk.lib.n
Guest
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| Posted: Sat Jul 29, 2006 12:06 am Post subject: Cross controlling ailerons and rudder in the landing approac |
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I would like to add:
Good definition of exact what happens base to final many times:
http://avstop.com/AC/FlightTraingHandbook/CrossedControlStall.html
Good brush up info:
http://avstop.com/AC/FlightTraingHandbook/CrossedControlStall.html
One point that not all pilots realize is that they can easily be flying an
airplane they are unfamiliar with even if they have a lot of hours in
type????
How?? Flying in thinner air than normal. Add humidity, rarefy, or go up in
altitude, and or fly at a heavier weight.
I have many more hours flying a 4 foot electric model than I do acting as
PIC of full scale. It is a unique electric model where the same wing is
used but have different electric power sources (Quick Sticks). AUW can
range between 19 oz to 46oz. That is a big change. There is not very many
times out where I don't spin it at least a few dozen turns with varying
AUWs.
When I was perfecting my flying and Quick Sticks, there were times with
the same AUWs, same CGs where I could not get into a good fully developed
spin?? Then there were times I would inadvertent enter a spin that was
unrecoverable??? It was kind of like the tail that wags the dog with me
fooling with changing the CG to tweak.
Variable was thickness of air!! Heavier usual will enter a spin easier,
and harder to recover for a given CG and air density.
Worst case is thin air, heavy and aft CG. Thin air on my model has the
greatest effect.
Just because you practiced spins on a 172 at 68 degrees 2 people and half
tanks, gives you way too much confidence with 4 people at gross, and 90
degrees at 2500 feet AGL with high humidity.
Here is reason why. Lets say you put an airspeed indicator on the rudder
of a 172 facing 90 degrees to rudder where we can measure airspeed
sideways in a spin. Lets keep the weight the same and CG the same in 2
scenarios. First lets let a spin fully develop into a 1000 foot deep hole
in Death Valley when it is 50 degrees below zero and a dew point of 100
degrees below zero, airspeed indicator would normalize at lets say 20
knots. Then lets go up to 18,000 feet where it is 110 degrees with a dew
point of 100 degrees. (Our 172 is a XXP with a 450HP PT6 turbo prop, and
airframe is constructed out of unobtanium so AUW is the same as a 180HP
Hawk) and let a spin fully develop, the airspeed indicator would normalize
at, you guessed it, 20 knots???
The difference is in Death Valley you would most likly be spinning less
RPM than a Cub on a normal day at sea level, but at 18K would be spinning
faster than a maple leaf could ever hope for. At 18K the a spin will much
more easily develop without trying, and once entered since the rudder is
most likely no where near effective enough to allow a recovery. Add more
to AUW, much worst, and go aft CG even much more worstererer.
One thing I use in models, and since so successful with models, full scale
as well is a pseudo eyes off, ears off airspeed indicator, stall
prewarner. Simple stupid. Do a very slight pitch up. That's it! When you
know your aeroplane, by doing this you can tell when response is sluggish,
you are getting close to stall. Great aid for final flare, steep turns or
when flying downwind where your ground speed can fool you into thinking
you have plenty of airspeed. After a while it is second nature, kind of
like counter steering on a motorcycle to avoid a threat. It will never
trick you like fast ground speed could when the wind shifted 180 degrees 3
seconds before touchdown and is giving you a tailwind. Works too with
roll, when in steep turns at lower speeds, you can feel ailerons begin to
get mushy, if you did nothing more than lower the nose you can feel much
more better response.
Works great on models when you are not in plane, works great when in
plane.
Remember nobody says you need to keep altitude when making turns, practice
up high, and try doing the worst things you can to enter a spin, and see
by just dropping the nose a little how much harder it is to enter a spin.
If you fly by using throttle to control altitude, and pitch to control
speed, if you overshot center line, go ahead and make a coordinated turn,
just don't pull back as hard as you need to maintain altitude, drop nose a
bit, you will gain a bit of airspeed, you will not pull as many gs but
most important keep your angle of attack lower. Add a bit of power and
sort when wings are near level. If you don't have enough runway to sort
out just go around.
If in a coordinated steep turn, if you must roll out quick, dropping the
nose helps a lot as well to prevent the low wing from stalling.
My main point for all this rambling, is try all this testing not just in
thick air, try it in thin air and heavy. You may realize you are flying
something that is very different from what you are expecting to be flying.
Ron Parigoris
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rparigor(at)suffolk.lib.n
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| Posted: Sat Jul 29, 2006 12:56 am Post subject: Cross controlling ailerons and rudder in the landing approac |
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Ooooops
Good brush up info:
http://www.theultralightplace.com/stall_&_spin.htm
Ron Parigoris
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