Inter rib lacing

[Bruce Caldwell]

Can someone tell me if I need to do inter rib lacing on a 46 BC12D? When I took it apart, it didn't have it. My AI says if it wasn't there then you don't need it. HELP!

[Ray36048]

Re: Inter rib lacing

Inter rib lacing is used to prevent the ribs from twisting when the fabric is drawn tight. After that is complete it has no function. If the ribs are twisted, there is no way to repair it other than remove the fabric. There is an argument that the installation manual for the fabric process STC tells you to use it. If it not there, you do not conform to the STC. I would use it, just like the manual says.

[d.grimm]

Re: Inter rib lacing

I had a mouse get into a J-4 wing once. All he chewed was that inter rib lacing.
My FSDO told me that it was part of the STC for the cover and that required it to be installed.
It does nothing after it's covered, just part of the approved process.
Dave

[Mark Bowden]

Re: Inter rib lacing

Handy reference, note chapter 3 and to your question page 4.

https://www.faa.gov/regulations_policies/handbooks_manuals/aircraft/amt_airframe_handbook/

If the STC says to use bracing tape and it wasn't, legally you are not airworthy as that would be a deviation from STC technique. Technique and methods are part of the STC just like the approved materials. Nothing wrong with mice eating only brace tape after recover is done.

Maybe this is good bait to keep mice from chewing on lacing and spars, lol.

[Scott]

Re: Inter rib lacing

inter-rib lacing gives you the opportunity to make small adjustment to the ribs to help get them straight (straight ribs are aerodynamically better, and look better, if those things are important to you).

There is also a tendency for the rib top flange to "roll" over bit with fabric tension. Bracing helps the ribs resist this throughout the life of the fabric.
S

[Bruce Caldwell]

Re: Inter rib lacing

Thanks guys! Don't know what I'd do without your!!!!