It was a warm spring day and severe clear was forecast for the entire day. My friend, Ray, and I planned to fly from the Solberg airport (N51) to Ocean City, New Jersey (26N), to visit a friend and have lunch. We are both members of a flying club based at Solberg and frequently fly together for company and to share the cost. We are both “seasoned” pilots (some would say old). The plan that day was for Ray to fly to Ocean City and for me to fly back.
It would be about a 50-minute flight in the club’s Piper Archer. Before the flight we topped off both tanks. Ray checked the fuel for water and color. Everything was good. We pushed the airplane back and departed. The flight was uneventful—well, almost. As we approached Ocean City, suddenly the engine became very quiet. Anyone who has experienced an engine failure knows the lump you get in your throat. Our first thought was oh, bother (cleaned up for publication).
This is where our years of experience paid off. Ray did everything right. He determined he could make the field from our present position. He turned on the electric fuel pump. The engine gave a brief roar and died again. He switched to the right tank and, after what seemed like an eternity, the engine started and continued to run. We checked the fuel gauge and saw that the left tank was showing empty. We could see that the fuel cap was still on. We obviously had a leak in the left tank because our fuel burn would have only been about eight gallons for the trip.
Ray made a normal landing and taxied to the parking area. We got out to see what had happened. The left side of the fuselage and the trailing edge of the flap were covered with blue dye. The tank was completely empty. The quick drain did not seem to be open. If it had been open before we left, we both were sure we would have seen a trail of fuel when we had pushed the airplane back after fueling.
We removed the top cowl to check for evidence of leaks, and found none. With the fuel selector on the right tank, Ray turned on the electric fuel pump while I looked for possible leaks in the engine compartment. There were none.
We had flown the full trip to Ocean City (except for the few minutes to land) on the left tank, so the right tank was full. We both were familiar with the airplane and the fuel system and were comfortable flying home on the right tank. So, after a quick lunch at the airport diner and a short visit with our friend, we departed for Solberg Airport. This time I was flying. You can be sure I was checking the fuel gauge as we flew.
After landing I taxied to the maintenance shop. Ray and I helped the mechanic remove the left tank. I fully expected to see a crack in the tank or the fuel line broken or detached. We found nothing that could explain the fuel loss. There was only minimal staining near the hose that connects the tank to the airplane. The mechanic pressurized the tank and brushed on soapy water. No leaks were found. He checked all of the hoses and could not determine any reason for the loss of fuel. We reassembled the airplane and warned the other club members to keep an eye on the fuel gauges.
The airplane has now been flying for more than four years with no reoccurrence of fuel loss, but I have a theory. I believe that when Ray tested the fuel before we left, a “mud dauber” (or something like it) plugged the quick drain after Ray took his sample. During our flight to Ocean City, the vibration partially cleared the bug blockage and the fuel leaked out.
Whatever caused the fuel loss remains a mystery. However, we both learned that even on a short flight—and even though you know you have ample fuel on board—always check the fuel gauges.
