Harness anchor oops.

[Seansull]

To make a long story short, I match drilled my F636 harness anchors in front of F1007 bulkhead instead of the F1008 bulkhead. (Page 10-14 Step #2)

I now have 3 holes in the longeron on each side. I am concerned with the integrity of the longeron with these additional holes. I am thinking I can go ahead and install the anchor (not for use, just to act as a doubler) and order an additional pair for the correct location.

Any thoughts anyone has will be greatly appreciated!

 

[flion]

Wow, you put lightening holes in your longeron? My gut says that you can probably just move on, but I'd advise you to take pictures and query Vans. If the holes matter, I don't think a doubler will help; any failure would come from lateral stresses causing cracking at the holes. You'd need to clamp between two doublers to spread out the stresses. Obviously, the longeron can stand to have a few holes drilled through the web side (consider the longeron like a bulkhead; the face against the skin is the flange so the other face is the web). It can even carry the stress of the restraint system. So I suspect that it will be just fine but that's seat-of-the-pants estimation.

By the way, if Van's does recommend sandwiching the area with doublers, don't use your anchors as doublers and order new. Fabricate doublers to fit from scrap; it'll be neater and cheaper. In the meantime, while you wait for a verdict, go ahead and install the anchors in the right spot.

 

[Seansull]

Thanks Patrick!

As you guessed, Vans said just put bolts in the holes and move on. They said I could sandwich the area with doublers and rivet it all together if it would make me sleep better at night.

I appreciate your response and I will try to keep the lightening hole design up to Vans from now on!