I noticed a nose-wheel shimmy that started last week. It happened on roll-out. I called Cirrus and they said to test the nose-wheel lateral (castering) tension by tilting the a/c up and pressing the nosewheel. Should be 10-20 lbs of force to move it back on forth. I tried this and sure enough, it moved with almost no force – I didn’t need to measure the force with a fish scale.
So during lunch in Prince George, BC, (in AK now), I asked a mechanic to take a look at it. What he found was alarming. Not only was the castellated nut that holds the nosewheel on to the vertical shaft coming from the nose strut completely off, but there was no evidence that there had ever been a cotter pin installed.
I let Cirrus know about it.
I don’t know, of course, if any other a/c were built this way, but if this happens, the mechanic said that your nosewheel could fall off.