Today Craig and I worked on installing the rear spar reinforcement cap per section 191 of the wing manual. This is an 1/8” strip of aluminum that is riveted to the top of the rear spar just to the outside of rib #6.
We started by assembling the aileron pulley and bracket that will be riveted on top of the reinforcement cap in the next step. We did this because there is a hole that lines up between the pulley bracket and the cap. With that hole lined up and the bracket clamped in place, we were able to slide the cap back and forth along the spar a very slight amount to make sure that a string line from the front spar through the pulley bracket would run straight down the center aileron hanger.
Ensuring the rear spar reinforcement cap is placed correctly
Once the cap was in place side-to-side, we ensured that it was centered front-to-back on the spar on both ends and clamped it down. Ensuring that the cap is centered front-to-back is extremely important since it determines where the holes are drilled in the spar cap. If you are off in your placement then you could accidentally drill into the web or part of the cap you aren’t supposed to.
The reinforcement cap in position and clamped down
After checking a few more times to ensure that the reinforcement cap was placed correctly, we started match drilling the holes through the cap and the spar. We started at the inboard end and worked our way out drilling every 3rd hole and placing a cleco in them after drilling. I did the drilling and Craig helped ensure that I had the drill straight up-and-down. Before drilling each new hole we checked to ensure that the cap was still centered and made slight adjustments if necessary.
After reaching the end and placing the last cleco, we went back and drilled the remaining holes with the exception of the hole that is match drilled with the pulley bracket. At this point we called it a day.
The cap with the holes drilled and cleco’d to the spar
Wing Manual (Extended Fuel), CCEX-004 Rev. 2.02, Pages 92-94 ↩