Ben Owen

FUELING UP SAFELY

Some of our members have had problems in fueling their aircraft, and we have received a number of calls from people who are quite concerned about this process. Fueling is a rather simple procedure, but it can be dangerous. If you handle it properly and think about what you're doing, you shouldn't have any problems. Plastic fuel cans and funnels are believed to be safer than metal, as far as the hazards from static electricity during fueling goes. They are not. We have Dick Roemer to thank for the suggestion that plastic fuel containers should have metal screening stuffed inside them, and that this metal screening should be connected to a static ground that comes out through the filler neck. It should be possible to place the alligator clip on the end of the wire that attaches to this metal screening to another wire without removing the cap from this plastic tank. Plastic tanks should be grounded in this fashion. We are all quite familiar with static electricity and what happens when you run a comb over wool fabric. Instant static electricity, right? The same thing happens when fuel flows over a plastic surface — static electricity builds up and the more fuel you flow, the more the static electricity is generated. The same is true when gasoline flows through a hose — static electricity is generated. If you have any doubts about this, I suggest you read the letter from EAA member F. H. Frantz, Jr. in the Letters To The Editor section, page 4, November 1987 Sport Aviation. The cure for static electricity is grounding of all components in the fueling chain. EAA member Lee Hurry of Hopkins, MN recalls that WW II liaison aircraft had a ground cable trailing from the axle area bolt (he still has an L-4 original) and a grounding jack receptacle on the airframe. Unfortunately, we found trailing wires aren't the best ground. A good positive connection to bare metal by an alligator clip is a good

connection. Most larger military aircraft, including his Fairchild 24, had SC (static conducting) tires. Lee reports that fire and explosions can be best prevented by grounding airplanes, grounding fuel containers, using metal funnels and following the proper connecting sequence. We thank Oshkosh Fire Department Captain Bob Vajgrt who provided us with the National Fire Protection Association Standard for Aircraft Fuel Servicing NFPA407. It is a little lengthy to reproduce here, but it does have some excellent guidelines.

First of all, you are going to need a "Y" cable. Splice in about a 4' length of cable to the middle of about an 8' length of cable with alligator clips at the three ends. Lamp cord should work for this "Y" cable — keep it as short as possible. This is used when fueling from gas station filling pumps to portable cans. A suggestion — use metal cans and funnels, as they are much easier to ground. Sand a bare metal contact patch on both for the clips. Attach one end of the "Y" cable to the portable can, one to the pump nozzle and one to the funnel. Open the tank cap, insert the funnel, then the nozzle and flow. When fueling is complete, stop the flow, withdraw the nozzle and put it away, withdraw the funnel, cap the portable tank and disconnect the "Y" cable from the funnel, then from the nozzle and the can. Ordinary plastic funnels or other non-conducting materials can increase static generation. In addition, the use of chamois as a filter is extremely hazardous (where do you store it in an airplane?). When fueling an aircraft from a portable can, the bond between the nozzle and the tank is most essential and is to be maintained throughout the fueling operation — until after the fuel tank filler cap has been closed. Here is where your "Y" static ground cable comes into use again. One of the "Y" ends should be attached to the can. The other end of the "Y" is attached to the airframe for

metal aircraft, or directly to the fuel tank inlet if it is a plastic or wooden aircraft. The other end is attached to the funnel. This means that before you open the tank on your aircraft, and before you open the fueling can, the aircraft fuel tank, metal funnel and metal fueling can are all bonded one to the other. When done fueling, reverse the operation. If you want to be safer, ground the tank to the metal ground provided for that purpose (on the ground). Under the National Fire Protection Agency code, if you are servicing at less than 25 gallons per minute and using less than 1 -1 /4" diameter hose, you only need to bond when fueling, you don't need to ground. If you want to ground, you are going to need another wire with two alligator clips and attach one end to the tank and the other to the metal ground provided. If there is no ground, use the tiedown metal fixture in the ground, not the loose tiedown ring attached to it. It is best not to use vinyl hose. If you must use it, you should have an outside ground wire taped to the hose grounded to the metal tank all the way to a grounded metal nozzle at the end of the hose. Auto gas stations and aircraft fueling points have grounded pumps, tanks and special grounded hoses. You don't see the hose ground wires as they are imbedded in the hose — grounding the nozzle to the hose and to the pump (and ground). It is also required that a fire extinguisher be on hand while fueling the aircraft. Where the open hose discharge capacity of the aircraft fueling system or equipment is not more than 200 gallons per minute, at least two extinguishers having a rating of not less than 20-B each shall be provided. Of course, the usual provisions against not having open flames in the fueling area, etc. should be observed.

EAA'er D. Y. Alldredge has devised this nice rig to help hold his tank in place while refueling. SPORT AVIATION 61