46-44-05: Engine Mounting Bolts

46-44-05 CESSNA: (Was Mandatory Note 5 of AD-768-4.) Applies Only to 120 and 140 Aircraft Serial Numbers 8001 to 8517, Inclusive. Compliance required prior to January 1, 1947. Replace each of the four internal wrenching bolts which attach the engine to the engine mount with an AN 6 bolt and a special offset washer. AN 6-47 bolts should be used at the upper fittings and AN 6-35 bolts at the lower fittings. The special washer is made of 4130 steel 7/8 inch in diameter and 1/4 inch in thickness with a through hole 0.377 inch in diameter and the O.D. machined to a 0.600-inch diameter a depth of 1/8 inch. The 0.600 inch-diameter offset fits into the aft end of the attachment fitting and the head of the replacement bolt bears directly on the special washer. Also, an AN 960-616 washer should be added between the nut and the AN 970-6 washer at the front face of the rubber bushing. This change is made to prevent the bolts from pulling through the 1 1/2-inch diameter x 0.049-inch plate welded to the front of each fitting. (Cessna Service Letter No. 18 covers this same subject.)