Tunnel Access Panels

I ordered two Airward tunnel access panels to install into the forward fuselage tunnel. As other builders have noted, this simplifies access to the fuel filter and fuel lines during inspections. I could have fashioned my own panels but I took the simple approach here.

The kit is complete but the hole spacing in the reinforcement plates is slightly off.

The instructions have you align the plates 3 holes forward of the seat vertical wall but this position would conflict with the fuel selector bracket. I match drilled one hole before stopping and double-checking alignment with everything else. I have an extra hole to fill with a rivet but glad again for pausing before moving forward.

I ended up moving the plates to the fourth hole, the position showed here. This provides clearance from the fuel selector bracket.

Tip: Note that the two reinforcing plates aren’t symmetrical. If installing on both sides of the tunnel they need to mirror each other to be installed in the same position on both sides. This isn’t called out anywhere in the instructions.

I split the difference between the misaligned holes and match drilled carefully in the drill press with a side block to avoid the bit from drifting. The outermost holes in the aplates end up slightly oval where they are offset (about 1/32″).

I then drilled the corners to #10 and clecoed the cover plate into place to mark the hole. I then upsized the corners with a step drill.

I rough cut the hole with a jigsaw and finished the edges with a vixen file.

Slow and steady and eventually everything fit nicely.

I final-sized the reinforcement plate nutplate attach holes and countersunk these per the plans. The plans ask you to dimple the rivet holes for attaching to the ribs but I decided to dimple these instead for a stronger connection (the rib is barely thick enough for countersinking). I then dimpled the holes in the ribs to match.

I then countersank the screw holes in the cover plates. I used a guide hole drilled in a wood scrap to keep the countersinks from drifting.

Done! A bit of work but well worth it per other builders. Making inspections easier will be worth it long after the build is over.