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Date: Wed, 20 Jul 2005 16:42:51 -0400
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From: "Dan Schaefer" <dfs155@adelphia.net>
Subject: Nose gear collapse
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Bryan, sorry to hear about your gear collapse.

This may not be germane to your airplane as I fly an early 235, however
FWIW, the only time I noted any shimmy was when I decided to try a higher
air pressure in my nose wheel than recommended by the factory.

Don't know what tire pressure your manual recommends but mine calls for 25
psi in the nose. At that pressure, I always thought the tire looked like it
was on it's way to a flat  - also, the wear pattern showed that most of the
wear was on the outer edges of the tread leading me to believe that 25 psi
was way too low. Besides, I was getting tired of other pilots walking by and
saying things like "Hey Dan, your nose wheel is going flat", etc., etc.

Bottom line, I pumped it up to where I thought it "looked right" (about 35
psi) and gave it a try. (I have the oleo nose strut and figured the internal
damping would take care of any tendency to shimmy -  WRONG)! On my first
landing at that pressure, I got a violent shimmy! About the only thing that
helped at all was to get the stick back all the way to get some pressure off
the nose wheel. That didn't stop the shake though it seemed to reduce it
somewhat. The shimmy continued until I got below about 50 MPH. Fortunately,
after a thorough inspection I could find nothing cracked, broken or bent - I
guess I was just lucky! (Odd that I didn't get a shimmy on take-off as I
break ground at around 85 MPH).

Needless to say, I returned the nose wheel pressure to the original 25 psi
before the next flight and haven't had a single recurrence. I guess the old
saw, paraphrased, "When all else fails, stick with the instructions" is good
advice.

Dan Schaefer
Very early LNC2