Andair Fuel Cap Modification
Hello Everyone,
I recently had the final inspection completed on my RV-10 and one of the snags surprised me. The inspector was looking at my beautiful Andair fuel caps and asked me whether they were ground bonded to the airframe. I didn’t know so we took a multi-meter and checked to see if there was an electrical connection between the Andair sleeve that gets bonded into the original fuel neck in Van’s wing tank and the wing skin. There wasn’t.
This meant that I had to come up with a way to electrically connect the original neck of the fuel tank and the sleeve that gets bonded in with tank sealant.
What I did to correct this was to drill a hole in the Skirt of the Andair sleeve big enough to allow a 6-32 machine screw to almost pass through. I then drilled a smaller hole through the skirt of the tank filler neck right behind it. I had to countersink the outer hole so that the screw head would not interfere with the fuel cap. There is not much clearance. I used a tap and carefully started the threads in the Andair sleeve. I then threaded the screw that had been sharpened somewhat through both sleeves.
All of this had to be done carefully in order to keep any contaminants out of the fuel tank. I accomplished this by taking strips of masking tape and looping them down into the tank fill opening and just leaving the area exposed where I drilled the hole. When I finished I vacuumed out the hole and checked inside for filings. Anything that landed on the empty tank bottom was removed with a stick that had tape affixed to it sticky side out.
I tested the new configuration for continuity and found that electricity flowed from the inner sleeve to the wing skin. For all of the thinking it took to come up with a workable fix, it took only 10 minutes to actually perform the work.
The interesting thing about this problem is that Andair knows about it but couldn’t offer any suggestions as to a fix. I hope that this helps anyone else who has these fuel caps.
Keep on building,
Dave