This is embarrasing

While removing the rivets to comply with the HS service bulletin I slipped off the tail of one of the rivets and drilled through the spar. After sending pics to Vans and talking at length with them, their recommendation was to replace the spar and the HS 710 splice angle. I finally took the parts to a Aircraft sheet metal repair shop locally and got a second opinion. They took measurements and sent pics to a structural engineer. They said that the load would transfer to the doubler and new angle and as long as I debured both holes I should be fine. I called Vans back and they basically said that they couldn't perform load analysis for each builder with specific situations like mine and as long as an FAA repair station ok'd the repair then they had no problem with it. Let me say I understand Vans position and am grateful for their builders support helping novice builders like me with issues that arise. My problem with replacing the spar is that I am concerned with further damage as I have already done extensive fiberglass work on the tip. If I mess up the skin taking off all that glass then I'm looking at just building a whole new stab. (Cost of parts vs. stab kit) almost a wash. So I thought I would reach out one last time before making the repair to those on the forum that have expertise with sheet metal repair. I understand the whole just replace it for peace of mind, but am really just hoping to get input from those with an expert opinion.






Thanks,

Build on! Maybe throw an extra rivet in it.

Replace

I am in the "replace" camp. Why?

First, I would always worry about whether the repair shop was right. I view the tail as a vulnerable part with respect to g loading and want peace of mind when I fly.

Second, I am sure you would disclose this repair to any future owner and this would be detrimental to resale value.

If you are worried about creating more damage drilling out the rivets get someone with a more experience to do it for you. It is not hard to do without damage provided you follow good practices. Tedious but not hard (I recently drilled out a few hundred rivets without hurting any of the holes).

Maxrate said:

After sending pics to Vans and talking at length with them, their recommendation was to replace the spar and the HS 710 splice angle.

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Maxrate said:

but am really just hoping to get input from those with an expert opinion.

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'twould seem to me that you already got THE expert opinion.

I would agree that you have already asked and gotten the answer, you just didn't like the answer. My experience with this sort of thing is that the prospect of doing it right, or redoing something that I did that wasn't right, is always daunting before you actually dive in, but once you're doing it, it's not so bad. You've had what we refer to as a gumption robbing experience and the only solution is to plug your nose, shut your eyes and dive back in again! Although, I would recommend your eyes be open

Getting some expert eyes to watch your work will probably be a great thing too. Sometimes little tips from people who are watching you work can be life-changing in how much they help!

Remember, it's all for education and recreation. Keep to the mantra:

"It's a hobby, it's a hobby, it's a hobby"!

Lazy me vs Engineer me.

Mike S said:

'twould seem to me that you already got THE expert opinion.

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Vans made the design and knows what the loading is for those rivets. That design information has been augmented with analysis and many years of field learning experiences. While there are other opinions, Vans is the one to follow, especially in the area of structural. They are pretty practical.

Hard as it is to accept, get over it and replace the parts. Getting started is harder than getting it done. Happens to me all the time. Lazy me vs. engineer me.

Like Yogi said, it is 90% mental, and the other 50% is physical.

Follow the manufacturers recommendation is my vote

I'd replace it. I recently finished the same SB on my already-built-but-not-yet-flying hstab, and I worried about doing the same sort of thing to mine. Note that there are a bunch more of holes to drill later in the modification process, which fall between those holes you drilled out as well -- not sure you'll have room for them anyhow when you get deeper into the SB.

And, from my non-professioanl perspective, it's a load-bearing spar. I'd err on the side of caution and just build a new one. Van's crew said to do it, and I listen to them. Now, I wouldn't like it much, but I'd do it. Second build's usually better than the first anyhow!

By the way, this rivet removal tool (Avery sells it) is great for performing this SB (and I have used it a few other times since).