Strut Tie Down Rings?

[Ryan Smith]

Hi all,

I recently had an opportunity to purchase some flush rivet (later model) struts to replace the original Hi-Lok struts on my airplane (S/N 20408). I would like to get some new tie down rings to go with my shiny new(er) struts and a cursory search for them doesn’t turn up as many search results as I would have thought.

Where can I purchase new tie down rings?

Thank you!

Ryan

[n2582d]

Original part number is 0523609. Appears to be a steel ring welded to an AN bolt. The L-19 uses p/n 0620110-1. Air Repair should have them at a reasonable price. Later model C-172’s use p/n 052613-1 which appear to be forged eye bolts. Preferred Airparts has two new ones in stock. McFarlane also sells these but curiously says, “this item is not approved for the wing strut locations.” If it’s bling you’re after check out these stainless steel eyebolts.

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Before buying them I’d get your mechanic’s opinion on this statement of theirs: “It’s our understanding from the FAA publications we’ve read, that tiedown eye bolts are considered fasteners used as replacements and are not subject to FAA approval and are exempt from the provisions of Section 21.303(b)(4) of the FAR. They are classified as "small standard parts". They don’t affect aircraft airworthiness, unless you forget to untie your plane before flying.”

A couple of thoughts regarding eyebolt strength. The 170B IPC calls for using AN365-524 nuts with elastic inserts. Newer model 172s use the considerably stronger MS21042L5 nut. Pay attention to the angle the rope is fastened to the eyebolt. As discussed here, pulling at an angle “will significantly lower working load limits … .”