Lighten That Nosewheel

[pelmet]

This incident shows how much damage nosewheel shimmy can cause. Usually, it is not due to the damper failing completely and can be greatly reduced by simply pulling back on the control column which should be done quickly. I did have a complete damper failure once on a C182 and the shimmy was really bad and nothing could be done to stop it except slow down. Not fun.

And you are in this undesirable situation where only slowing down to some unknown lower speed will help but doing it quickly to lessen the amount of shimmy time may be offset by more shimmy because braking puts more pressure on the nosegear. Perhaps that it was the case here......

The privately operated Cessna 210B, C-FANX, was operating from High River, AB (CEN4) to Olds-
Didsbury, AB (CEA3) with just the pilot on board. The aircraft landed on Runway 28 at CEA3 and

during rollout the nose landing gear shimmy damper failed resulting in significant vibrations. As the
shimmy oscillations increased, the nose landing gear fork fractured and separated from the nose
landing gear strut. The aircraft came to rest on the nose landing gear strut, which remained down
and locked. The pilot was able to maintain control of the aircraft on the runway surface. The pilot
was not injured. Damage was limited to the nose landing gear assembly and propeller.

[CpnCrunch]

It happened to me a couple of times when my oleo was slightly underinflated.

[co-joe]

I had that in a BE20, the shimmy was so bad I thought the nose gear was going to come off. Full back pressure had no effect, and applying brakes made it worse. I had to just ride it out and hope for the best. The shimmy damper had no oil at all in it and they said there was signs of corrosion inside. The vibration was so intense the entire instrument panel was slamming back and forth against the walls of the cockpit. It's funny how an experience like that can shape how you land aeroplanes for years after.

[digits_]

Isn't lowering the nose just as effective? It's my understanding that shimmy happens when a fine balance between nosewheel pressure, friction, speed, nosewheel angle and side load is reached. Changing any of those values could stop shimmy.

[photofly]

Definitely back pressure, and get off the brakes.

[2R]

I had that in a BE20, the shimmy was so bad I thought the nose gear was going to come off. Full back pressure had no effect, and applying brakes made it worse. I had to just ride it out and hope for the best. The shimmy damper had no oil at all in it and they said there was signs of corrosion inside. The vibration was so intense the entire instrument panel was slamming back and forth against the walls of the cockpit. It's funny how an experience like that can shape how you land aeroplanes for years after.

Ground checked serviceable , good to go

[OtherRedBaron]

Isn't lowering the nose just as effective? It's my understanding that shimmy happens when a fine balance between nosewheel pressure, friction, speed, nosewheel angle and side load is reached. Changing any of those values could stop shimmy.

You may be right - but reducing the weight on the nosewheel will also have the effect of reducing the vibration imparted to the rest of the airframe. Lowering the nosewheel makes that part worse.

While both methods may solve the shimmy issue, only one will reduce damage to the airframe if the shimmy problem isn't rectified; the other makes it worse.