Service Bulletins

The year 2008 will go down in my checkbook as the most expensive maintenance year to date, with very little flying done. There were three service bulletins that I needed to get implemented and they were all going to be a big hassle in their own way. Two of them were from Van’s. These would be the new nosewheel fork upgrade, and the safetying of the internal fuel tank fitting. The third was the Gen-3 upgrade described elsewhere in this journal. A fourth item that I had been intending to do was not a service bulletin, but rather a change to the fuel line pickups to add filters to them. This is needed because I changed the fuel plumbing to eliminate the gascolator/filter and move the high pressure pumps into the cabin.

Since the nosewheel fork upgrade required pulling the nose gear leg and sending it out for machining, I decided to work on the other two items while waiting.

I used several adjustable cargo straps tied to several concrete blocks and a 50lb bucket of sand to hold the tail down slightly so I could take the weight off of the nose. I then used a small hydraulic jack to hold the front of the airplane up. After that, dropping the nosegear was easy, and it was just a waiting game until it came back from the machinist.

Meanwhile, back at the hangar, I spent a full day pulling those fucking fuel tanks off the wing. To put this in perspective, the last time the bolts on the back side of the spar were tightened down was during construction of the wing when the bottom skins were off. Getting ANY tools into the access ports along with my beefy hands turned out to be quite a drama. Some bolts were easy and could be done with just a stubby ratchet. Some were quite tricky and required a combination of contortionist manuevers, air ratchets and a variety of wrenches and swear words.

Once the tanks were finally off the wing, I could get to the next bit of unpleasant business which was carefully removing the prosealed shut end covers. Some acetone, small knives, scrapers and screwdrivers were used in various combinations and eventually, the covers were pried open.

As a side note, I have been running standard auto gas (yes, with ethanol) for quite a while. When I buy the gas, I always add Stabil additive in case the plane sits for a while. There have been all kinds of horrific descriptions of destruction and mayhem regarding both ethanol based fuel and the use of Stabil, and based on what I am seeing, I would say there has been absolutely no impact to any part of the fuel tanks or other components. There was absolutely no corrosion in the tanks or fittings, and there was no sludgey material left over from the Stabil. In fact, the tanks were just as clean and shiny as the day I sealed them shut three years ago.

It turns out that opening up the tanks was probably a really good thing. I found that one of the fuel pick up lines was loose. Not from a loose fitting, but actually from a bad flare. In the other tank, I found that the vent line fitting was extremely loose. The first thing I did was tighten down both vent fittings and put proseal on them.

The next thing was to install some new pick up lines. I ended up using standard automotive fuel line pickup “sock”. These are part number FS38. It took a while working with the NAPA guys to figure out the equivalent part, but they did have them in stock. I fabricated two new pickup lines with some fresh AN fittings, and carefully adjusted them so that the fuel socks would lay flat in the lowest part of the tank. I attached them to the fuel line by drilling a small hole through the attachment point and the tubing, then used a piece of safety wire to tie everything together. A generous blob of proseal to seal up around the connection finished the job. Oh, and I didn’t forget to do Van’s safety wire job on the other end either.

Reassembling the end covers and prosealing them shut was basically a repeat of the process used during the original build, including the leak test using a couple of balloons. This was after the usual two week wait to make sure the proseal was completely cured. Unfortunately, remounting the tanks onto the wings was the same scenario described above, only in reverse. I am really, really glad this is not a regular maintenance issue, or I would really, really be hating Van’s design team.

At some point in all this, the gear leg arrived safely back, and the nose gear was reassembled uneventfully. I used all of the same brackets I had originally, so there was a fairly minimal impact.