N738VZ

On May 17, 2000, approximately 1130 hours UTC (Greenwich) a Cessna 172N, N738VZ, registered to and operated by ASA International of Central Florida, Inc., and being flown by a US commercial pilot, was destroyed when the aircraft was ditched and sank in the Atlantic Ocean approximately 350 nautical miles west of Portugal. The pilot was uninjured and was rescued approximately 4.5 hours later. Visual meteorological day conditions existed and an instrument flight plan was in effect. The flight, which was a ferry flight operating under 14CFR91, had departed Santa Maria, Azores, at 0620 UTC, and was destined for La Coruna, Spain.

The pilot, a resident of Seattle, Washington, reported the accident to the Safety Board's Northwest Regional Office on June 5, 2000. He was telephonically interviewed and subsequently provided a corroborating written statement (attached) with the following information.

A Spanish flight school had recently purchased N738VZ and the operator was to deliver the aircraft to Spain after the installation of a long-range (ferry) fuel system. The pilot reported that the aircraft underwent an annual inspection in April of 2000, and that approximately 39 hours of flight time had transpired between that time and the ditching.

The pilot departed from Tampa, Florida, on May 11th, in N738VZ, and arrived in Bangor, Maine, the following day (May 12th). He reported that during this stage of the trip the aircraft functioned normally and he calculated a fuel burn rate of 9 gallons per hour. Telford Aviation installed the long-range fuel system on May 13th at Bangor.

The long-range fuel system consisted of a 124 US gallon welded aluminum tank located behind the pilot and replacing the two rear passenger seats. The tank was fitted with a filler neck, a vent line and an outflow line that provided fuel to the engine. The outflow line, attached at the bottom aft of the tank, and proceeded forward to a shut-off valve. Upstream of the shut-off valve were two electric boost pumps in series. Between the shutoff valve and the first boost pump was a translucent length of line designed to allow the pilot to observe fluid flow or any air bubbles that might be passing through the line. Upstream of the second boost pump the outflow line was tied into the aircraft's regular fuel line at a point between the regular wing tank shutoff valve and the engine.

The aircraft was also equipped with two standard 21.5-gallon fuel tanks, one in each wing. The total usable fuel was 40.0 gallons, which was fed to the engine through the wing tank fuel selector valve and thence to the carburetor/engine. There was no boost pump for the wing tanks system, and fuel was subsequently fed by gravity (refer to DIAGRAM I).

The pilot reported that he departed Bangor, Maine, on May 15th destined initially for Gander, Newfoundland, with full wing tanks and 80 gallons of fuel in the long-range tank. He indicated that ordinarily he would have flown nonstop to the Azores, but due to a headwind condition, he chose to refuel at Gander. The flight to Gander was uneventful and the pilot reported "the aircraft and ferry systems performed normally the entire time." After refueling, the aircraft subsequently departed Gander arriving at Santa Maria on May 16th.

The aircraft was refueled at Santa Maria with 421 liters (111.22 US gallons) of fuel resulting in 43 US gallons total in the wing tanks and the remaining fuel in the long-range tank (refer to ATTACHMENT FR-I).

The pilot reported that with the fuel acquired at Santa Maria along with the remaining fuel from the flight from Gander he would have an endurance of 13.5 hours for the approximately 860 nautical mile final leg (refer to ATTACHMENT C-I). He also expected that the final leg's flight duration would be 9.5 hours and that he "expected to exhaust the ferry fuel just as I reached the mainland, and would land with nearly full wings." The aircraft was preflighted with no discrepancies noted and the flight departed for its final destination, La Coruna, Spain, at 0620 UTC on May 17th.

As per the pilot's standard procedure, he departed utilizing fuel from both wing tanks, and on this flight climbed to an altitude of 7,000 feet. Approximately 30 minutes after takeoff he switched the fuel supply to the long-range tank and shut off wing tank fuel to the engine. Approximately 5 hours into cruise, and near the midpoint of the flight, the engine quit.

The pilot stated that "When the engine stopped, it behaved like it does when ferry fuel is exhausted: it sputtered for two or three seconds and went quiet, with the propeller wind milling. With this type of airplane I normally run the ferry tank completely empty, and am used to the engine quitting at the appropriate time. When the remaining fuel is selected [wing tanks], it takes no more than five seconds for this engine to restart. This time was about three and a half hours early, so I knew immediately there was a problem."

He described the events following the power loss as follows: "Flying the plane with my left hand, I reached down between the seats with my right [hand] and switched the second boost pump on, and confirmed that the valve was open. The clear section of hose appeared to have fuel inside it, but without waiting for a result I immediately switched the aircraft fuel selector to BOTH, and closed the ferry valve. I left the pumps running. I put the mixture forward to full rich, and pumped the throttle about ten times, which resulted in the engine sputtering slightly for two seconds and then quitting again. I slowed to best glide speed, pulled the carb heat on, moved the ignition switch around to different positions, and checked the primer in...."

Unable to achieve a restart, the pilot transitioned to a glide, made a MAYDAY radio call on high frequency and prepared to ditch. The pilot executed a successful ditching near 40 degrees 30 minutes north latitude and 015 degrees 30 minutes west longitude during which the aircraft sustained horizontal stabilizer damage but remained upright. He exited the aircraft and was located within 30 minutes by an Egyptian C-130. A US National Guard C-130 dropped a life raft approximately 90 minutes later and a Portuguese fishing vessel picked up the pilot several hours later. The aircraft remained afloat in a steep nose down attitude for several hours and ultimately sank in 5,000 meters of water.