Skidding turns

[[email protected]]

Yesterday on a short sight-seeing x-cntry I noticed the following
flight characteristic of a 1975 C150: whenever I turned to the left,
especially with low power setting, the ball indicated a skid with no
bottom rudder at all.

Explanations I've seen usually are illustrating the danger of skidding
a turn onto final, at high AoA, the typical scenario being tightening
a turn to not overshoot the runway. The inside wing and the rudder are
pointing toward the ground. The ball indicates skid. The pilot gives
more back pressure -- that's where you can get into big trouble.

But I noticed a substantial ball deflection indicating skid with
neutral rudder (shallow turn, not anywhere near critical AoA, by the
way).

In a left turn it seemed to me to take a fair bit of top rudder to
keep the ball centered. That seems weird to me. It doesn't happen in
the 152 or 172 I fly so I'm wondering if other people have seen this
in 150s (or other aircraft) or maybe the ball indicator has a problem?

I remember during my checkride in the same aircraft the ball showed
substantial skid on a demo approach the DE was doing after I had
passed the checkride. He saw it too and corrected, but the plane's
behavior seemed to catch him off guard as well.

[[email protected]]

On Feb 19, 9:33 am, wrote:
> Yesterday on a short sight-seeing x-cntry I noticed the following
> flight characteristic of a 1975 C150: whenever I turned to the left,
> especially with low power setting, the ball indicated a skid with no
> bottom rudder at all.
>
> Explanations I've seen usually are illustrating the danger of skidding
> a turn onto final, at high AoA, the typical scenario being tightening
> a turn to not overshoot the runway. The inside wing and the rudder are
> pointing toward the ground. The ball indicates skid. The pilot gives
> more back pressure -- that's where you can get into big trouble.
>
> But I noticed a substantial ball deflection indicating skid with
> neutral rudder (shallow turn, not anywhere near critical AoA, by the
> way).
>
> In a left turn it seemed to me to take a fair bit of top rudder to
> keep the ball centered. That seems weird to me. It doesn't happen in
> the 152 or 172 I fly so I'm wondering if other people have seen this
> in 150s (or other aircraft) or maybe the ball indicator has a problem?
>
> I remember during my checkride in the same aircraft the ball showed
> substantial skid on a demo approach the DE was doing after I had
> passed the checkride. He saw it too and corrected, but the plane's
> behavior seemed to catch him off guard as well.

You have a broken rudder bar spring. Cessna's springs regularly do
that and will have the airplane uncoordinated, requiring constant
rudder force on one pedal to keep things centered. The unbroken spring
is pulling on one pedal.
The other, more remote possibility, is a worn nosewheel
centering cam. The nosewheel is the rudder's centering system while in
flight on a Cessna single, with the sprung steering pushrods acting as
system centers. Cessna rudder systems are frequently found badly
misrigged, too, since too few mechanics refer to the maintenance
manuals while fixing them.

Dan

[[email protected]]

On Feb 19, 9:33 am, wrote:
> Yesterday on a short sight-seeing x-cntry I noticed the following
> flight characteristic of a 1975 C150: whenever I turned to the left,
> especially with low power setting, the ball indicated a skid with no
> bottom rudder at all.
>
> Explanations I've seen usually are illustrating the danger of skidding
> a turn onto final, at high AoA, the typical scenario being tightening
> a turn to not overshoot the runway. The inside wing and the rudder are
> pointing toward the ground. The ball indicates skid. The pilot gives
> more back pressure -- that's where you can get into big trouble.
>
> But I noticed a substantial ball deflection indicating skid with
> neutral rudder (shallow turn, not anywhere near critical AoA, by the
> way).
>
> In a left turn it seemed to me to take a fair bit of top rudder to
> keep the ball centered. That seems weird to me. It doesn't happen in
> the 152 or 172 I fly so I'm wondering if other people have seen this
> in 150s (or other aircraft) or maybe the ball indicator has a problem?
>
> I remember during my checkride in the same aircraft the ball showed
> substantial skid on a demo approach the DE was doing after I had
> passed the checkride. He saw it too and corrected, but the plane's
> behavior seemed to catch him off guard as well.

You have a broken rudder bar spring. Cessna's springs regularly do
that and will have the airplane uncoordinated, requiring constant
rudder force on one pedal to keep things centered. The unbroken spring
is pulling on one pedal.
The other, more remote possibility, is a worn nosewheel
centering cam. The nosewheel is the rudder's centering system while in
flight on a Cessna single, with the sprung steering pushrods acting as
system centers. Cessna rudder systems are frequently found badly
misrigged, too, since too few mechanics refer to the maintenance
manuals while fixing them.

Dan

[Robert M. Gary]

On Feb 19, 8:33*am, wrote:

> In a left turn it seemed to me to take a fair bit of top rudder to
> keep the ball centered. That seems weird to me. It doesn't happen in
> the 152 or 172 I fly so I'm wondering if other people have seen this
> in 150s (or other aircraft) or maybe the ball indicator has a problem?

Sure you weren't flying a helicopter? :)

-Robert

[[email protected]]

On Feb 19, 11:40*am, wrote:
> On Feb 19, 9:33 am, wrote:
>
>
>
>
>
> > Yesterday on a short sight-seeing x-cntry I noticed the following
> > flight characteristic of a 1975 C150: whenever I turned to the left,
> > especially with low power setting, the ball indicated a skid with no
> > bottom rudder at all.
>
> > Explanations I've seen usually are illustrating the danger of skidding
> > a turn onto final, at high AoA, the typical scenario being tightening
> > a turn to not overshoot the runway. The inside wing and the rudder are
> > pointing toward the ground. The ball indicates skid. The pilot gives
> > more back pressure -- that's where you can get into big trouble.
>
> > But I noticed a substantial ball deflection indicating skid with
> > neutral rudder (shallow turn, not anywhere near critical AoA, by the
> > way).
>
> > In a left turn it seemed to me to take a fair bit of top rudder to
> > keep the ball centered. That seems weird to me. It doesn't happen in
> > the 152 or 172 I fly so I'm wondering if other people have seen this
> > in 150s (or other aircraft) or maybe the ball indicator has a problem?
>
> > I remember during my checkride in the same aircraft the ball showed
> > substantial skid on a demo approach the DE was doing after I had
> > passed the checkride. He saw it too and corrected, but the plane's
> > behavior seemed to catch him off guard as well.
>
> * *You have a broken rudder bar spring. Cessna's springs regularly do
> that and will have the airplane uncoordinated, requiring constant
> rudder force on one pedal to keep things centered. The unbroken spring
> is pulling on one pedal.
> * * * *The other, more remote possibility, is a worn nosewheel
> centering cam. The nosewheel is the rudder's centering system while in
> flight on a Cessna single, with the sprung steering pushrods acting as
> system centers. Cessna rudder systems are frequently found badly
> misrigged, too, since too few mechanics refer to the maintenance
> manuals while fixing them.
>
> * * * *Dan- Hide quoted text -
>
> - Show quoted text -

Hey thanks, I will convey that info in terms of a question to the FBO
and see what they say. I'm sure other pilots have noted this weirdness
as well.

[[email protected]]

On Feb 19, 12:26*pm, "Robert M. Gary" > wrote:
> On Feb 19, 8:33*am, wrote:
>
> > In a left turn it seemed to me to take a fair bit of top rudder to
> > keep the ball centered. That seems weird to me. It doesn't happen in
> > the 152 or 172 I fly so I'm wondering if other people have seen this
> > in 150s (or other aircraft) or maybe the ball indicator has a problem?
>
> Sure you weren't flying a helicopter? :)
>
> -Robert

Hah! For my own safety and that of everyone else I hope I'm not
hallucinating *that* bad! ;)

[Robert M. Gary]

On Feb 19, 5:12*pm, wrote:

> Hey thanks, I will convey that info in terms of a question to the FBO
> and see what they say. I'm sure other pilots have noted this weirdness
> as well.

Remember that the FBO's CFIs are probably flying this plane more often
than solo renters. I would be surprised if the FBO doesn't already
know. Either they are waiting on the part, waiting for the next 100
hours, or waiting for someone to crash as a result of this. ;)

-robert

[[email protected]]

On Feb 19, 6:14 pm, "Robert M. Gary" > wrote:
> On Feb 19, 5:12 pm, wrote:
>
> > Hey thanks, I will convey that info in terms of a question to the FBO
> > and see what they say. I'm sure other pilots have noted this weirdness
> > as well.
>
> Remember that the FBO's CFIs are probably flying this plane more often
> than solo renters. I would be surprised if the FBO doesn't already
> know. Either they are waiting on the part, waiting for the next 100
> hours, or waiting for someone to crash as a result of this. ;)
>
> -robert

The way to find out: push the tail down to raise the nosewheel
off the ground, and see if the rudder centers. If not, one spring is
probably busted.
Be carerful pushing the tail down. The front spar in the stab is
a little light and cracks easily if this is done regularly. 172s are
worse. Much worse.

Dan

[[email protected]]

> * * *The way to find out: push the tail down to raise the nosewheel
> off the ground, and see if the rudder centers. If not, one spring is
> probably busted.
> * * *Be carerful pushing the tail down. The front spar in the stab is
> a little light and cracks easily if this is done regularly. 172s are
> worse. Much worse.
>
> * * *Dan

that shouldn't happen if you push down on the last two fuselage
formers before the vertical tail, should it?

[Bob Martin]

> Be careful pushing the tail down. The front spar in the stab is
> a little light and cracks easily if this is done regularly. 172s are
> worse. Much worse.
>
> Dan

So _that's_ why the flight school always flipped out when we did that...

Now I fly a plane where the tail is _always_ down. Of course, that makes landing slightly
more challenging...

[C J Campbell[_1_]]

On 2008-02-19 17:14:55 -0800, "Robert M. Gary" > said:

> On Feb 19, 5:12*pm, wrote:
>
>> Hey thanks, I will convey that info in terms of a question to the FBO
>> and see what they say. I'm sure other pilots have noted this weirdness
>> as well.
>
> Remember that the FBO's CFIs are probably flying this plane more often
> than solo renters. I would be surprised if the FBO doesn't already
> know. Either they are waiting on the part, waiting for the next 100
> hours, or waiting for someone to crash as a result of this. ;)
>
> -robert

The plane is not airworthy if this is the condition. I doubt that the
CFIs are aware of it. Even if they were, they might not report it
because they don't want the plane taken off the line for repairs.

A broken rudder bar spring can cause the rudder to jamb in a spin
recovery. After that there is no way to recover from the spin. Pushing
on the rudder harder just jambs it harder.

See here for a related accident report:

http://www.tsb.gc.ca/en/reports/air/1998/a98q0114/a98q0114.asp
--
Waddling Eagle
World Famous Flight Instructor

[[email protected]]

On Feb 19, 6:26 pm, wrote:
> > The way to find out: push the tail down to raise the nosewheel
> > off the ground, and see if the rudder centers. If not, one spring is
> > probably busted.
> > Be carerful pushing the tail down. The front spar in the stab is
> > a little light and cracks easily if this is done regularly. 172s are
> > worse. Much worse.
>
> > Dan
>
> that shouldn't happen if you push down on the last two fuselage
> formers before the vertical tail, should it?

Got to be careful that you don't wrinkle the skin on either
side of the formers. None of this stuff is very stiff. Another way to
get the nose off is to put the prop horizontal and lift it, putting
your hands on the blades on either side of the spinner. DON'T EVER put
any force on the spinner. They don't like that.
Turn the prop backwards. Very carefully. Never take a silent
engine for granted. Some of them waken rather easily. In a bad mood.

Dan

[[email protected]]

On Feb 19, 6:58 pm, Bob Martin > wrote:
>
> So _that's_ why the flight school always flipped out when we did that...

You got it. Cessna has a service bulletin on the subject.
Pushing the stab down places high forces on the front part of the
stab, while in the air the loads are 40% back; the aft spar's
construction reflects the greater load it carries. The front spar is
really light and flexes through the big lightening hole in the center,
and cracks in four places. Very expensive. A little dangerous, too.

>
> Now I fly a plane where the tail is _always_ down. Of course, that makes landing slightly
> more challenging...

Airplanes are supposed to be built that way. Just compare the
taildragger and trike versions of the Maule (or even the Helio
Courier). What pilot would ever say that the trike looks right? (What
*real* pilot?:-))

Dan

[[email protected]]

On Feb 19, 9:42 pm, C J Campbell >
wrote:

> The plane is not airworthy if this is the condition. I doubt that the
> CFIs are aware of it. Even if they were, they might not report it
> because they don't want the plane taken off the line for repairs.
>
> A broken rudder bar spring can cause the rudder to jamb in a spin
> recovery. After that there is no way to recover from the spin. Pushing
> on the rudder harder just jambs it harder.
>
> See here for a related accident report:
>
> http://www.tsb.gc.ca/en/reports/air/1998/a98q0114/a98q0114.asp

That airplane had two problems: A busted spring, which really
wasn't the issue, and badly worn rudder hinges, which allowed the
rudder stops to override the stop bolt heads and lock in a fully-
deflected position. Since they couldn't get the spin rotation stopped,
they couldn't break the stall. The busted spring was just another
symptom of really poor maintenance. The FAA issued an AD on it.

Dan

[[email protected]]

wrote:
> On Feb 19, 6:26 pm, wrote:
> > > The way to find out: push the tail down to raise the nosewheel
> > > off the ground, and see if the rudder centers. If not, one spring is
> > > probably busted.
> > > Be carerful pushing the tail down. The front spar in the stab is
> > > a little light and cracks easily if this is done regularly. 172s are
> > > worse. Much worse.
> >
> > > Dan
> >
> > that shouldn't happen if you push down on the last two fuselage
> > formers before the vertical tail, should it?

> Got to be careful that you don't wrinkle the skin on either
> side of the formers. None of this stuff is very stiff. Another way to
> get the nose off is to put the prop horizontal and lift it, putting
> your hands on the blades on either side of the spinner. DON'T EVER put
> any force on the spinner. They don't like that.
> Turn the prop backwards. Very carefully. Never take a silent
> engine for granted. Some of them waken rather easily. In a bad mood.

> Dan

The way I was told to do it is to lay your upper body and arms across
the fueslage to spread the force as much as possible and never just
push down with your hands.

--
Jim Pennino

Remove .spam.sux to reply.

[WJRFlyBoy]

On Tue, 19 Feb 2008 21:08:08 -0800 (PST),
wrote:

>> See here for a related accident report:
>>
>> http://www.tsb.gc.ca/en/reports/air/1998/a98q0114/a98q0114.asp
>
> That airplane had two problems: A busted spring, which really
> wasn't the issue, and badly worn rudder hinges, which allowed the
> rudder stops to override the stop bolt heads and lock in a fully-
> deflected position. Since they couldn't get the spin rotation stopped,
> they couldn't break the stall. The busted spring was just another
> symptom of really poor maintenance. The FAA issued an AD on it.
>
> Dan

"The right elevator tip trailing edge had been broken and repaired with
aluminum foil tape, and the rudder bottom tip had two cracks of about 1.5
inches extending from a rivet hole which had been stop-drilled and painted.
No record was found of these repairs."

Not attempting to be dramatic, but isn't this at least gross negligence and
possibly accessory to 3rd degree manslaughter?
--
Remove numbers for gmail and for God's sake it ain't "gee" either!

[Joe Emenaker]

On Feb 19, 9:15 pm, wrote:
>
> The way I was told to do it is to lay your upper body and arms across
> the fueslage to spread the force as much as possible and never just
> push down with your hands.

Just adding my $0.02: My PP CFI was also an A&P for American Eagle.
What he had me do was to find the middle-most spar (by finding the
rows of rivets) and push down there right where it attaches to the
empenage while also pushing down on the empenage with the other hand.

- Joe

[WingFlaps]

On Feb 20, 8:24*pm, WJRFlyBoy > wrote:
> On Tue, 19 Feb 2008 21:08:08 -0800 (PST),
> wrote:
>
> >> See here for a related accident report:
>
> >>http://www.tsb.gc.ca/en/reports/air/1998/a98q0114/a98q0114.asp
>
> > * *That airplane had two problems: A busted spring, which really
> > wasn't the issue, and *badly worn rudder hinges, which allowed the
> > rudder stops to override the stop bolt heads and lock in a fully-
> > deflected position. Since they couldn't get the spin rotation stopped,
> > they couldn't break the stall. The busted spring was just another
> > symptom of really poor maintenance. The FAA issued an AD on it.
>
> > * * Dan
>
> "The right elevator tip trailing edge had been broken and repaired with
> aluminum foil tape, and the rudder bottom tip had two cracks of about 1.5
> inches extending from a rivet hole which had been stop-drilled and painted..
> No record was found of these repairs."
>
> Not attempting to be dramatic, but isn't this at least gross negligence and
> possibly accessory to 3rd degree manslaughter?
> --

No. He preflighted it and decided these were non-issues -right? (Now
I've not seen the cracks but I'd guess that a stop drilled a rivet
crack at the bottom of the tail is not likely to be an issue as not
near a hinge. the paint shows it's an old repair and the crack has
been stopped correctly).

Cheers

[Peter Dohm]

> wrote in message
...
On Feb 19, 11:40 am, wrote:
> On Feb 19, 9:33 am, wrote:
>
>
>
>
>
> > Yesterday on a short sight-seeing x-cntry I noticed the following
> > flight characteristic of a 1975 C150: whenever I turned to the left,
> > especially with low power setting, the ball indicated a skid with no
> > bottom rudder at all.
>
> > Explanations I've seen usually are illustrating the danger of skidding
> > a turn onto final, at high AoA, the typical scenario being tightening
> > a turn to not overshoot the runway. The inside wing and the rudder are
> > pointing toward the ground. The ball indicates skid. The pilot gives
> > more back pressure -- that's where you can get into big trouble.
>
> > But I noticed a substantial ball deflection indicating skid with
> > neutral rudder (shallow turn, not anywhere near critical AoA, by the
> > way).
>
> > In a left turn it seemed to me to take a fair bit of top rudder to
> > keep the ball centered. That seems weird to me. It doesn't happen in
> > the 152 or 172 I fly so I'm wondering if other people have seen this
> > in 150s (or other aircraft) or maybe the ball indicator has a problem?
>
> > I remember during my checkride in the same aircraft the ball showed
> > substantial skid on a demo approach the DE was doing after I had
> > passed the checkride. He saw it too and corrected, but the plane's
> > behavior seemed to catch him off guard as well.
>
> You have a broken rudder bar spring. Cessna's springs regularly do
> that and will have the airplane uncoordinated, requiring constant
> rudder force on one pedal to keep things centered. The unbroken spring
> is pulling on one pedal.
> The other, more remote possibility, is a worn nosewheel
> centering cam. The nosewheel is the rudder's centering system while in
> flight on a Cessna single, with the sprung steering pushrods acting as
> system centers. Cessna rudder systems are frequently found badly
> misrigged, too, since too few mechanics refer to the maintenance
> manuals while fixing them.
>
> Dan- Hide quoted text -
>
> - Show quoted text -

Hey thanks, I will convey that info in terms of a question to the FBO
and see what they say. I'm sure other pilots have noted this weirdness
as well.

---------------old post ends-----------

Sorry for putting this in the wrong place, there is a post missing on my
server.

Some of these planes had a little ground adjustable trim tab--which was
adjusted by the simple expedient of bending it by hand. It could obviously
be bent out of position by someone's knee or nearly anything else on the
ramp. I don't recall whether all 150s and 152s had the feature, and I only
ever flew one 152 that was obviously out of rig.

Peter

[[email protected]]

On Feb 20, 12:24 am, WJRFlyBoy > wrote:
> "The right elevator tip trailing edge had been broken and repaired with
> aluminum foil tape, and the rudder bottom tip had two cracks of about 1.5
> inches extending from a rivet hole which had been stop-drilled and painted.
> No record was found of these repairs."
>
> Not attempting to be dramatic, but isn't this at least gross negligence and
> possibly accessory to 3rd degree manslaughter?

Those are plastic tips. They all crack as they age and
shrink; in cold weather they contract. Try to find an older 150 or 172
without cracked plastic tips. We replace them with fiberglass Stene
Aviation tips. They're on the 'net. Their tips are far superior and
are cheaper than Cessna's plastic stuff.
The beef with those cracked and stopdrilled tips was that
no record was found of the repairs. Elevator tips (or top rudder caps)
that are cracked toward their front ends can fold back and foul
against the stab or fin. Those should be replaced.
The TSB guys detail everything in their reports. The
serious stuff was the worn rudder hinges and other bits, and the
broken rudder bar spring. I would imagine that there were LOTS of
snags that could have been written up on that airplane.

Dan

[[email protected]]

> No. He preflighted it and decided these were non-issues -right? (Now
> I've not seen the cracks but I'd guess that a stop drilled a rivet
> crack at the bottom of the tail is not likely to be an issue as not
> near a hinge. the paint shows it's an old repair and the crack has
> been stopped correctly).
>
> Cheers- Hide quoted text -
>
> - Show quoted text -

Well. Can't say anything was apparent about this on the ground during
the pre-flight. And nothing detectable through pressing on the rudder
pedals. I'll try the test recommended next time I'm out at the field.
In the meantime I'm about to bring this to the chief pilot's
attention.

[WJRFlyBoy]

On Wed, 20 Feb 2008 15:35:53 -0800 (PST), wrote:

>> No. He preflighted it and decided these were non-issues -right? (Now
>> I've not seen the cracks but I'd guess that a stop drilled a rivet
>> crack at the bottom of the tail is not likely to be an issue as not
>> near a hinge. the paint shows it's an old repair and the crack has
>> been stopped correctly).
>>
>> Cheers- Hide quoted text -
>>
>> - Show quoted text -
>
> Well. Can't say anything was apparent about this on the ground during
> the pre-flight. And nothing detectable through pressing on the rudder
> pedals. I'll try the test recommended next time I'm out at the field.
> In the meantime I'm about to bring this to the chief pilot's
> attention.

"The right elevator tip trailing edge had been broken and *repaired with
aluminum foil tape* was what I thought was grossly negligent.
--
Remove numbers for gmail and for God's sake it ain't "gee" either!

[[email protected]]

On Feb 21, 4:38 am, WJRFlyBoy > wrote:
> "The right elevator tip trailing edge had been broken and *repaired with
> aluminum foil tape* was what I thought was grossly negligent.

Right. That is extreme.

Dan

[[email protected]]

> > Well. Can't say anything was apparent about this on the ground during
> > the pre-flight. And nothing detectable through pressing on the rudder
> > pedals. I'll try the test recommended next time I'm out at the field.
> > In the meantime I'm about to bring this to the chief pilot's
> > attention.
>
> "The right elevator tip trailing edge had been broken and *repaired with
> aluminum foil tape* was what I thought was grossly negligent.
> --
> Remove numbers for gmail and for God's sake it ain't "gee" either!- Hide quoted text -
>
> - Show quoted text -

I now realize you guys are talking about a different plane, the Cessna
with the jammed rudder.

My confusion, sorry.

[Bertie the Bunyip[_24_]]

wrote in news:53965888-d44d-4d1d-b71d-
:

> On Feb 19, 6:14 pm, "Robert M. Gary" > wrote:
>> On Feb 19, 5:12 pm, wrote:
>>
>> > Hey thanks, I will convey that info in terms of a question to the FBO
>> > and see what they say. I'm sure other pilots have noted this weirdness
>> > as well.
>>
>> Remember that the FBO's CFIs are probably flying this plane more often
>> than solo renters. I would be surprised if the FBO doesn't already
>> know. Either they are waiting on the part, waiting for the next 100
>> hours, or waiting for someone to crash as a result of this. ;)
>>
>> -robert
>
> The way to find out: push the tail down to raise the nosewheel
> off the ground, and see if the rudder centers. If not, one spring is
> probably busted.
> Be carerful pushing the tail down. The front spar in the stab is
> a little light and cracks easily if this is done regularly. 172s are
> worse. Much worse.

that's right,. you shouldn't push these down by the leading ede of the
tail. You should always push on the fuselage bulkhead adjacent.



Bertie