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After the engine was stopped it was found that a number of the rags had become draped over the mixing valve and had closed off about 80 per cent of the air intake area at this point. This valve and the tube leading from it to the carburetor grid, were then removed. A number of rags fell from the bottom of the carburetor grid. Thirty rags were found still attached to the grid itself and were covering approximately 50 per cent of the grid area.
From this test two conclusions may be reached. First, a substantial quantity of small rags must enter the cold air duct to cause a loss of power in the engine; and second, if such a quantity of rags actually enters the cold air duct, most of them will remain in the induction system. It appears, therefore, that small rags of the type found in the induction system of the right engine of NC 13359 could not have caused the loss of power in that engine. While it would have been possible for a few small rags to have been passed through the propeller, thence through the screen at the opening of the cold air duct, and thence through the induction system to the carburetor grid, it is extremely unlikely that a number of such rags sufficient to have stopped the engine could have taken this course. Moreover, if a quantity of small rags sufficient to have stopped the engine had entered the cold air duct, they would have been found in the induction system after the accident. The only way for them to get out would have been through the carburetor into the engine where they would have been burned.
