During the approach at night, the Bellanca 17-30A experienced a total loss of engine power, and the pilot performed a forced landing into trees near Monroe, Ga., seriously injuring two.
Subsequent examination of the engine revealed that the oil filter adapter was loose and that it was installed incorrectly with two copper crush gaskets rather than with one copper crush gasket and one fiber gasket per the manufacturer’s installation instructions.
The fiber gasket would have held the required torque for the fitting; however, the copper crush gasket did not hold the required torque.
Because the oil filter adapter was loose, oil leaked from the engine, which led to the failure of the Nos. 4 and 5 connecting rods due to a lack of oil lubrication.
The oil filter adapter was not original equipment on the engine. Although it could be installed under a supplemental type certificate, a review of maintenance and aircraft records did not reveal any entry or record pertaining to the installation of the oil filter adapter.
The airplane had been operated for about 70 hours since its most recent annual inspection, which was performed about a year before the accident.
It could not be determined when the oil filter adapter was incorrectly installed.
Although the pilot stated that he had fueled the airplane with 100 low-lead aviation gasoline, automobile gasoline was recovered from the fuel tanks.
The higher-compression ratio engine was not designed or approved to operate on automobile gasoline, and engine examinations revealed that it had been operating at higher temperatures due to the use of automobile gasoline.
If the engine had not failed due to oil starvation, it is likely that it would have soon begun to detonate due to the use of the improper fuel.
The NTSB determined the probable cause as the improper installation of the oil filter adapter at an unknown time, which resulted in an oil leak and subsequent oil starvation to the engine.
NTSB Identification: ERA14LA436
This September 2014 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.