Was I wrong?

was there any crosswind? usually the nose wheel only shimmies if there is a side load on it, either because of crosswind or an out-of-alignment condition, or uneaven tread wear due to poor pilot technique over time.

a little back-pressure will solve the problem, like everyone said, and also proper trim tab setting will prevent it.

p.s. tailwheels also can shimmy if they are improperly adjusted, worn, bent, or are the locking type with a side-load due to crosswind or improper technique, or a combination of these. when it happens to me, it is usually improper technique.
 
This is one of the few things I don't like about flying in the Tomahawk as opposed to a 150. The Tomahawk does not have a shimmy dampener, so it is not uncommon for the nose wheel to shimmy.
 
If servicing the shimmy damper isn't doing it anymore then the scissor link bushings and bolts need to be looked at. There should be almost no play in the scissor link. If that's good and tight the shimmy damper could be empty and you wont get any shimmy.
 
esa17 said:
Fixed

And an 8hr working day, yes. I am serious. It's a gigantic pain in the six to have to drop everything just to fix a very minor squawk.
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Are you a mechanic? Then that is your job. It also a pain in my arse to deal with things I consider minor/annoying such as crabby passengers, delays, feds, bad coffee and writing up seemingly insignificant items so know-it-all mechanics can smirk at me for being an idiot. But is my job and I take care of them every time smirks or not.
 
bike21 said:
Are you a mechanic? Then that is your job. It also a pain in my arse to deal with things I consider minor/annoying such as crabby passengers, delays, feds, bad coffee and writing up seemingly insignificant items so know-it-all mechanics can smirk at me for being an idiot. But is my job and I take care of them every time smirks or not.
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Yes actually, I am.

Dealing with these sort of issues might seem pressing to you but when I'm in the middle of rewiring a panel or reassembling the flywheel and fan scroll assembly on a Schweitzer dealing with such issues can quickly become a safety issue. The fact is there are priorities in all aspects of life and a problem that has been around since dirt was new doesn't really rank that high on my to-do list.

When the situation allows I will be happy to fix it but I'm not going to drop what I'm doing every time and skip all the way across the ramp with a can of 5606 in a picnic basket each time one of these things wobbles.


What are you going to deal with first? A MEL'd item or a passengers cold coffee?
 
esa17 said:
Yes actually, I am.

Dealing with these sort of issues might seem pressing to you but when I'm in the middle of rewiring a panel or reassembling the flywheel and fan scroll assembly on a Schweitzer dealing with such issues can quickly become a safety issue. The fact is there are priorities in all aspects of life and a problem that has been around since dirt was new doesn't really rank that high on my to-do list.

When the situation allows I will be happy to fix it but I'm not going to drop what I'm doing every time and skip all the way across the ramp with a can of 5606 in a picnic basket each time one of these things wobbles.


What are you going to deal with first? A MEL'd item or a passengers cold coffee?
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I am with you on the priorities, but just wanted to make sure we weren't going down the road of ignoring the seemingly little things until they go away. As you likely know it is most certainly those seemingly nuance type items in life that sneak up and bite us down the road.
 
cmill said:
Well, thats well and good, but this is trainer. If you dont want shimmy, then dont fly a trainer. They could fix the shimmy, then have a student go out and mess up the dampener after one landing. Its just not worth the effort for a plane thats going to be abused like that.
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Funny, because where I work, if it's got a shimmy, it's gotta be fixed, and it only takes a few minutes usually. We have had engine mounts crack from shimmies, so they are on top of them. If you train properly, as in don't land it on the freakin nose wheel, then shimmies are rare events. I haven't had a shimmy in a 172/152/150 in a LONG time where I work currently. The palce where I was at as a second job, I had to deal with shimmies all the time, which is one of the reasons why I quit, because I was told it was "normal. It's not normal, and wasn't desgined into the airplane, so it should be treated as such. There is simply no excuse for poor maint. And telling someone that the shimmy is "normal" is incorrect, wrong, and leads to bad habbits later on down the line. My point is where do you draw the line between "normal" and "that needs to be adressed." If it's bad enough to loose directional control, and you endup taking out a runway light, what are you going to tell the feds? "They all do it, so it must be normal." Do you think thats gonna keep you from being violated? I have a feeling you'd get violated.

I remember reading an article in AOPA a while back about a gentleman who bent back a Nav/Strobe glare shield on a 182, and was violated for flying an un-airworth aircraft. So, in essence, if it hasn't been at the very least been defered, it is not airworthy.

The OP did the right thing by letting someone know that it had a shimmy, and if he felt unsafe flying the airplane, then thats his authority as PIC. There should be no questions about something when a person excersies their judgement, even about things like this.
 
bike21 said:
I am with you on the priorities, but just wanted to make sure we weren't going down the road of ignoring the seemingly little things until they go away. As you likely know it is most certainly those seemingly nuance type items in life that sneak up and bite us down the road.
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Good deal, I certainly am not advocating ignoring something until it goes away because it won't. Smoking hole creation issues first then on to the other things.
 
esa17 said:
Yes actually, I am.

Dealing with these sort of issues might seem pressing to you but when I'm in the middle of rewiring a panel or reassembling the flywheel and fan scroll assembly on a Schweitzer dealing with such issues can quickly become a safety issue. The fact is there are priorities in all aspects of life and a problem that has been around since dirt was new doesn't really rank that high on my to-do list.

When the situation allows I will be happy to fix it but I'm not going to drop what I'm doing every time and skip all the way across the ramp with a can of 5606 in a picnic basket each time one of these things wobbles.


What are you going to deal with first? A MEL'd item or a passengers cold coffee?
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You get paid by the hour- what do you care what you're fixing at any given time? Can't drop everything and fix the SD right away? Tell the owner it'll be a while. If that keeps the airplane grounded and unable to produce revenue, that should be incentive to the owner to get it fixed right. Look, the pilot isn't an A&P. All he needs to know is the noseweel shimmies and it's not supposed to. He has no way to judge if it's minor or if it's on the verge of falling off the airplane, that's your job and you get paid to do it.
 
Were you wrong? Nope.

You're the airman, YOU make the go/no-go decision. If you're uncomfortable, it's your call, not the mechanics. People may or may not talk schmack around the FBO, but ultimately you deal with the consequences (both positive and negative) of the choice you make.

Besides, at this point, you're the customer anyway. If you rented a car from AVIS and it had chattery brakes and the power steering was a little questionable, would you take it back? Certainly.
 
I think both the OP and the mechanic are right in their own ways.

The OP found the first airplane defective based on his experience as PIC. The fact that he had no problem with the second airplane proves there was a "problem" with the first airplane.

The mechanic is correct in that nosewheel shimmy in a 152 can be minimized or overcome by using max nose up elevator during taxi, takeoff, and landing rollout. This "advanced" technique can not be expected to be in a lower time pilots bag of tricks. As a CFI, you teach your students to be "safe", not necessarily teach them how to baby a bad shimmy damper.

I would welcome the chance to show a student what happens when the nosewheel shimmy's and what to do if it happens. Telling a pilot he is at fault for a nosewheel shimmy, however, is most likely not appropriate.

Charging the pilot for the .2 time involved is very much chicken poopy, and should be brought up to management.
 
mshunter said:
Funny, because where I work, if it's got a shimmy, it's gotta be fixed, and it only takes a few minutes usually. We have had engine mounts crack from shimmies, so they are on top of them. If you train properly, as in don't land it on the freakin nose wheel, then shimmies are rare events. I haven't had a shimmy in a 172/152/150 in a LONG time where I work currently. The palce where I was at as a second job, I had to deal with shimmies all the time, which is one of the reasons why I quit, because I was told it was "normal. It's not normal, and wasn't desgined into the airplane, so it should be treated as such. There is simply no excuse for poor maint. And telling someone that the shimmy is "normal" is incorrect, wrong, and leads to bad habbits later on down the line. My point is where do you draw the line between "normal" and "that needs to be adressed." If it's bad enough to loose directional control, and you endup taking out a runway light, what are you going to tell the feds? "They all do it, so it must be normal." Do you think thats gonna keep you from being violated? I have a feeling you'd get violated.

I remember reading an article in AOPA a while back about a gentleman who bent back a Nav/Strobe glare shield on a 182, and was violated for flying an un-airworth aircraft. So, in essence, if it hasn't been at the very least been defered, it is not airworthy.

The OP did the right thing by letting someone know that it had a shimmy, and if he felt unsafe flying the airplane, then thats his authority as PIC. There should be no questions about something when a person excersies their judgement, even about things like this.
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:yeahthat: :yeahthat: :yeahthat:

This thread is a classic example of poor attitudes towards maintenance by some pilots/mechanics/flight schools/FBOs.

As has been said numerous times, a shimmy is not "normal" and should not be allowed to continue.

In response to those who have said a shimmy re-develops only a few hours after being repaired....that's just not true. At least not as long as its fixed correctly.

To prove this, I looked back at the maintenance records for both of our primary trainers. The most recent shimmy dampener squawk/repair on one aircraft was 265 tach hours ago. On the other aircraft, the most recent squawk/repair for a shimmy was recorded 1,073 tach hours ago. They are both currently running smooth.

Now, it's entirely possible that either of those shimmy dampeners could have been serviced during a 100 hour inspection or something as preventative maintenance and not logged into our computer system. But even that would go to show the importance of preventative maintenance.

However, the one point I'd like to add, is that I don't see any problem with *briefly* deferring the squawk for a shimmy dampener that is worn out. And when I say, "briefly," I'm talking about a day or two, for the sake of maintenance scheduling. I would not instantly ground an aircraft at the first sign of a wobble. However, I would clearly print it on the dispatch sheet for pilots to be aware of, talk to them about keeping pressure off the nosewheel as much as practical, and scheduling it with a mechanic within a day or two. It's safe to fly, but shouldn't be ignored, either.
 
I'm going with the "yes & no" answer as well as far as "NOT PAYING." I'm believing you felt the aircraft was not airworthy for you to fly, so nope. . .I'm not paying. The fact I turned around and squawked it says I didn't fly; I aint logging .2 in my logbook as well, so I aint paying.

Now, if refusal to pay potentially affects future training or airplane rental, then long term, you might wind up having to go someplace else if you continue to get stuck a request to pay. . .

. . .so, I wouldn't pay, but the owners may be more demanding in the future when you rent.
 
I didn't bother to read all the replies, but here is my opinion:

Cessna nosewheels are known to shimmy. There are a couple of known reasons why they do this.
1) the bolts and bushings in the scissor linkage going bad
2) underinflated tires
3) tire out of balance

If these items are taken care of, the shimmy dampener is almost unnecessary. With that said, the shimmy dampener could be a problem.

I am responsible for maintenance on the 172 I train people in. When someone says the nosewheel is shimmying, or I'm in the plane and it shimmys, we get it fixed. We've replaced the bushings and bolts in the scissor gear, and the thing DOES NOT shimmy.

No, we don't ground it while we're waiting on parts, but we get it fixed before it gets bad.

It is NEVER wrong to take a plane back to the ramp because you're not sure it's safe. NEVER.
 
MFT1Air said:
I'm going with the "yes & no" answer as well as far as "NOT PAYING." I'm believing you felt the aircraft was not airworthy for you to fly, so nope. . .I'm not paying. The fact I turned around and squawked it says I didn't fly; I aint logging .2 in my logbook as well, so I aint paying.

Now, if refusal to pay potentially affects future training or airplane rental, then long term, you might wind up having to go someplace else if you continue to get stuck a request to pay. . .

. . .so, I wouldn't pay, but the owners may be more demanding in the future when you rent.
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Eventually I got it taken off the bill, so at least that is good.
 
Mike H said:
You get paid by the hour- what do you care what you're fixing at any given time? Can't drop everything and fix the SD right away? Tell the owner it'll be a while. If that keeps the airplane grounded and unable to produce revenue, that should be incentive to the owner to get it fixed right. Look, the pilot isn't an A&P. All he needs to know is the noseweel shimmies and it's not supposed to. He has no way to judge if it's minor or if it's on the verge of falling off the airplane, that's your job and you get paid to do it.
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What do I care? Well, that's easy. Believe it or not being a mechanic can be quite stressful. It's a lot more complex than just turning wrenches which sometimes means I go home with one hell of a headache because I spent the day figuring out how not to kill someone.

I don't care that I get paid by the hour but I do care that I don't kill someone. The problem that a lot of the posters in this thread are failing to realize is that sometimes a 40yr old airplane is going to have quirks and do things it was never intended to do, sorry. I watched a 172 nose gear come in which was solid as a rock a few days ago but had play in places it shouldn't. As soon as we shimmed it up tight it shook the hell out of the plane. We did everything right and it still didn't behave. I guess instead of telling the owner what to look out for while we figured out what to do we should have turned the plane into a popcan.

I hate the statement "what do you care" Actually it makes my blood boil because I care a lot as do most mechanics. Next time the plane you fly most goes down for inspection help the mechanics out. You'll be surprised how many times things show up that pilots missed, ignored, and just plain didn't know about. Now, if you're the perfect pilot who has never missed something I'll gladly eat my words.

Please take the time to learn what's going on instead of making the decision to run a flight school out of business.

If the pilot screws up, the pilot dies. If the mechanic screws up the pilot does. At this point in my career I'm having to be extra vigilant because often times I'm the mechanic and the pilot. So yeah, I care a lot.
 
I remember having this issue with a 152 I used when I was going after my PVT, and it happened when I was soloing. I was told the same thing: more back pressure. That helped it considerably, but I think you made the right call about not flying it if you didn't like what was going on with the plane. Nothing wrong with squawking a plane you're not ok with, after all you are the one that has to deal with it and I'm sure other pilots would appreciate the shimmy dampener being fixed up a bit.

I'm sure you are not the only low time guy flying it, and it's possible that shimmy might scare the crap out of some student pilot that screws up because of it. By all means, squawk it if it seems like a safety issue.
 
esa17 said:
I hate the statement "what do you care" Actually it makes my blood boil because I care a lot as do most mechanics. Next time the plane you fly most goes down for inspection help the mechanics out. You'll be surprised how many times things show up that pilots missed, ignored, and just plain didn't know about. Now, if you're the perfect pilot who has never missed something I'll gladly eat my words.
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That flippant comment is simply a statement of ignorance by pilots who either don't truly understand what A/Ps or Repairmen do, who look down upon them as lesser people, or who simply don't care to learn what it is they do.

At least thats been my experience.
 
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