Long-EZ. Defiant, Electric Boost Fuel Pump Alert
October 1988
Returning to his home base airport after a flight, a Southern California Long-EZ pilot was approaching the 45 degree entry to downwind when, abruptly, his engine quit. He was unsuccessful in getting it restarted but, to his credit, he flew the airplane, announced his situation and made an uneventful, successful landing. Feeling a little weak around the knees, he pushed his airplane into his hangar and went home. The next day, he conducted a careful examination of the aircraft and discovered that the Facet solid-state fuel pump was completely blocked and would not allow any fuel to pass through to the engine driven mechanical pump! One of the two valves in the pump had deteriorated in the 100LL fuel and had worked its way out of the metal cage that normally prevents this, and had been sucked into a position that prevented the flow of fuel. The part number on the mounting flange of this pump was 480615.
The plunger valve was made of VITON- this pump is no longer being manufactured. Before next flight, check the part number of your pump. If you have one of the following part numbers 40023, 480615, 480616, remove the pump and replace it. The most desirable Facet solid-state pumps that we recommend are part #40108 for 12 volts and part # 40154 or 480610 for 24 volts. Both pump fuel at a regulated maximum 6 psi, and the valves in these pumps are pure nyIon which, other than swelling very slightly in avgas, are not affected nor do they deteriorate. The design of these valves (the foot valve and the plunger valve) are such that they cannot physically get into a position where they can prevent fuel from flowing through the boost pump. Both of the above pumps have AN-style, 370 flare fittings which fit 3/8" tube, AN 818-6. Nuts. Facet manufactures over one hundred variations of the small square solid-state fuel pumps.
The above two pumps have AN-type flare fittings machined right on the pump bodies and we prefer this type because they are easy to install (no elbows or nipples required), but also because these two models have only nylon valves, no rubber, Buna, or Viton. Many of FACET's other models have Viton plunger valves or Buna N check valves and these will deteriorate in avgas. These are specifically for use in some other liquid known not to affect these materials. To check your pump, remove it and look into the inlet and the outlet using a small flashlight and verify that the inlet valve (foot valve) is a round, white dome or ball (nylon), not a flat, black rubber disc. Verify that in the outlet there is a white nylon valve under a steel pin which crosses the port and retains this valve.
If this valve is dark gray or black (Viton), remove the pump before next flight and discard it. If you have to a pump with female pipe threads (to accept elbows or nipples) due to your firewall layout, choose one with 3/8 NPT female threads rather than the 1/8NPT female threads, but examine it closely to be sure it has while nylon valves in the inlet and the outlet ports. Discard it if there is any black or gray Viton, Buna N or rubber valves. If you have had your Facet fuel pump more than a year or so, you probably have one that could go bad. AT a cost of approximately $30.00, it is not worth the risk. Remove it, discard it and install a new one as called out.
We believe that the serious consequences that could result from a fuel supply stoppage, more than justifies the immediate replacement of any suspect pump. We have replaced the boost pumps on Burt's Defiant and on Mike and Sally's Long-EZ and we recommend in the strongest possible terms that you do the same.