DAKOTA LOW STRUTS

daviddillehay

Sitting for several months for big avionics upgrade, a mechanic tells me struts are low and is not airworthy. Is this common? What is the best course of action?

Dave Dillehay

N8442A

griff390

Dave;

The struts on your plane are oleo type. They contain hydraulic fluid, and are pressurized with air or nitrogen.

Oleo struts generally fail in 1 of 2 ways.

1. The internal O-ring seals inside the strut fail or leak out. Your struts use "red fluid", so you'll see oil on the strut, gear, or floor of the hangar.
2. The Schrader valve at the top of the strut or the seal between the strut and valve is leaking.

Start by having the struts pressurized, and see how long it takes for them to leak down. Put some soapy water or leak detection fluid (yes, it's a real product) around the valve at the top of the strut. If you see bubbles, it's leaking.

If you see leaking red fluid, you'll probably need to rebuild the struts. Not horribly difficult, but extremely messy.

empannin

Inflating the struts would be the first thing to try. Did they have it on jacks?

Did they do any work or is it just sitting?

Tom_Jax

If the struts are not completely collapsed, i.e. the outer housing sitting flush on the "knuckle" of the scissor, you still have fluid in the cylinder. If the shop still has a lot of work to do, I'd leave it collapsed until they finish, it protects the chrome of the strut. Have them pump it up with nitrogen, ideally using a strut pump, to book specs. I wouldn't be at all shocked if it holds and you're good, especially if you're up north in the cold.