C172 Shimmy

[Len]

Just land and keep the nose wheel in the air... Its good training for when your A320 nose gear cocks 90 degrees!

 

[a&p cfiguy]

As an A&P who's worked on 172 flight school aircraft for over three years, I can tell you exactly what's wrong. Most likely the steering collar is worn out and needs to be shimmed. Cessna makes three different size shims to accomplish this. This requires the whole nose strut to be removed the steering collar slid off, shims installed as required to get a tight fit, but not too tight that you can't steer the airplane, steering collar and nose strut reinstalled.

This is one of the most common complaints of 172s and one that usually goes unfixed for years because no one wants to do the job right! Everyone thinks they'll just service the shimmy dampener and it'll be okay. Or I'll just shim the torque links and that outta do it. Or maybe I'll replace the nose tire cause it may be out of balance. ALL of which do absolutly NOTHING! The shimmy dampener on a 172 is a joke! That tiny little thing couldn't stop a shopping cart from shimming. All the other things may make it a little better, but until you take out all the play in that worn out steering collar, it'll shimmy.

And NO, holding the nose off as long as possible is not the answer. That's just ignoring the problem. The more it shimmies, the more it's wearing out that firewall and eventally it'll just shimmy right off the plane (although I've never seen this happen, but it could). Tell your mechanic to do the job right.

 

[CutEmUp]

I've seen that happen. It was a 172RG and the nose gear had a shimmy. The mechanics tried all the usual things and the problem was mostly fixed. The next day, the plane came back in after it started to shimmy REALLY bad. One of the mounts actually started to tear itself apart. A vibration of any sort should be fixed ASAP or it will lead to something worse.