N1147M

On November 23, 1995, at 1945 mountain standard time, a Cessna 310J, N1147M, registered to a private owner, made a forced landing short of runway 17L at Centennial Airport, Englewood, Colorado. The two certified flight instructor pilots were not injured and three of the four passengers received minor injuries. The aircraft sustained substantial damage. Visual meteorological conditions prevailed for this cross country flight operating under Title 14 CFR Part 91 and an IFR flight plan was filed. The flight departed Crystal Minnesota, about 2 hours 45 minutes before the accident.

According to the pilot, the left engine lost all power while on final approach. He stated that he raised the landing gear and flaps and went to maximum power on the right engine. He did not feather the left propeller. He said that he could not arrest the descent and subsequently he made a gear up landing in a field approximately 300 feet short of the runway of intended landing. During landing, the aircraft struck a ditch, some dead tree stumps, and a fence.

Calculated fuel on board at the time of the accident was approximately 15 gallons in each main tank with residual fuel only in the auxiliary tanks. The pilot said he had the fuel selected to the main tanks, the mixtures rich and the boost pumps on high. These are the recommended procedures in the flight manual, except that the manual merely states "on" with regards to boost pumps.

Performance calculations were conducted by this investigator based on information provided by Cessna Aircraft and the pilot. According to those calculations, at the time of the accident, the aircraft weighed approximately 4,849 pounds having burned off 251 pounds of fuel en route. At that weight, using a pressure altitude of 5,883 feet above mean sea level, and an indicated airspeed of 112 miles per hour, the aircraft was capable of maintaining a negative rate of climb of 165 feet per minute (fpm) with the landing gear and flaps up and the inoperative engine windmilling. If the pilot had feathered the inoperative engine propeller, performance data indicates that the airplane should have been able to achieve a positive rate of climb of 283 fpm with the landing gear and flaps up.

On November 29, 1995, the left engine was examined at the facilities of Beegles Aircraft Services, Greeley, Colorado.

The top spark plugs exhibited eroded electrodes and an excessive gap. All exhibited a white color.

The fuel screen was removed from the metering unit and it had approximately 15 percent of its surface covered with lint. Fuel was present in the unit.

The engine was motored by use of the starter and all six cylinders produced compression. Mechanical continuity was established. A spark was observed emanating at the plugs connected to the left magneto during the engine motoring. Fuel was also observed being pumped out of the screen port on the metering unit.

The right magneto was removed and turned with an electric drill. It produced spark. It was noted that one tower was shorted to the case and arced to ground. The tower exhibited corrosion. (See attached photographs.)

Both the left main fuel transfer pump and boost pump were operationally tested and were serviceable.

The shielding on the left engine ignition wiring was separated at numerous points in the ignition harness and leakage to ground was observed during testing. (See attached photographs.)