NTSB Factual Report

On October 5, 2009, at 1200 central daylight time, a twin-engine Temco D-16A (“Twin Navion”), N124N, sustained substantial damage when it impacted tress and terrain near Eden Prairie, Minnesota, after a loss of power in one engine. A post impact fire consumed part of the airplane. The pilot, the sole occupant, was seriously injured. The 14 Code of Federal Regulations Part 91 personal flight departed Anoka, Minnesota, at 1140 and was en route to Flying Cloud Airport (FMC), Eden Prairie, Minnesota. Visual meteorological conditions prevailed at the time of the accident. No flight plan was filed.

The pilot reported that the airplane had just undergone its annual maintenance inspection, and that he was flying it back to FCM. He reported that about 8 miles from FCM, the left engine stopped producing power. He completed the shutdown checklist for the left engine and feathered the propeller. He applied full power to the right engine, but the airplane continued to lose altitude. There was no suitable landing area so he executed a forced landing to a large wooded area away from houses. He lowered the gear during the forced landing and pulled the right engine to idle upon impact with the trees. A small fire on the right side of the airplane ensued but was extinguished.

Numerous witnesses reported that they heard and/or saw the airplane as it flew overhead at a low altitude. All reported hearing a loud engine noise without any sputtering. One witness reported that the left propeller was not turning. Witnesses who rushed to the accident site reported that they had to break the airplane’s canopy glass in order to get it open. Then they assisted the pilot in exiting the airplane.

A Federal Aviation Administration (FAA) airworthiness inspector interviewed the pilot and examined the airplane. The pilot reported that he departed with 80 – 85 gallons of fuel on board with the center tank full. During cruise flight, the fuel selector was positioned on the center fuel tank. The pilot reported that he was cruising at 1,500 feet above mean sea level (FCM field elevation is 906 feet). When the airplane lost left engine power, he attempted to reestablish fuel flow to the left engine by turning on the electric fuel pump, and then switching fuel tanks. The inspection of the airplane revealed the electric fuel pump switch was in the ON position. The fuel selector valve was found between tank positions. The right propeller exhibited impact signatures consistent with a high engine power setting. The left propeller blades were straight with no power signatures exhibited.

The FAA airworthiness inspector tested the airplane’s fuel system utilizing Navion Service Bulletin No. 106A. The service bulletin is not applicable to the Temco (“Twin Navion”) aircraft, although many of the same components are used on both aircraft. The inspection revealed that the Bendix/Facet electric fuel pump found in the left engine nacelle exhibited blue staining on the top surface of the pump, which was consistent with a fuel leak. The inspector reported that the test of the electric fuel pump revealed that the end cap gasket had failed, which allowed air to be drawn into the system by both the electric and engine driven fuel pumps. The install date and total time of the pump and end cap gasket could not be determined from the maintenance records.

The airplane was a twin-engine Temco D-16A, serial number TTN-60 that was issued its airworthiness certificate on July 19, 1956. It was equipped with two 170-horsepower Lycoming O-340-A1A engines. The last annual maintenance inspection was conducted on October 1, 2009. The airplane had a total time of 3,587 hours at the time of the inspection.

The Navion Service Bulletin No. 106A was issued on May 1, 2007. This service bulletin was applicable to Navion aircraft, but not the Temco D-16A. The subject of the service bulletin was: Fuel system – Inspection of the fuel system continued safe operation. This is due to several recent Navion accidents caused by improper inspection and maintenance of the fuel system and related components.

The FAA issued Airworthiness Directive (AD) 2008-05-14 on April 16, 2008. This AD was applicable to Navion aircraft, but not the Temco D-16A. The AD required a one-time inspection of the entire fuel system and repetitive functional tests of certain fuel selector valves. The AD resulted from reports of airplane accidents associated with leaking or improperly operating fuel selector valves. The AD was issued to detect and correct fuel system leaks or improperly operating fuel selector valves, which could result in the disruption of fuel flow to the engine.

NTSB Probable Cause

A total loss of left engine power due to fuel starvation as a result of the failure of the engine's electric fuel pump end cap gasket, which allowed air to be drawn into the fuel system.