AD 47-33-06

47-33-06 BEECH: (Was Mandatory Note 1 of AD-770-1 and Mandatory Note 1 of AD- 765-1.) Applies to D18C, D18S and D18C-T Aircraft Serial Numbers AA-1 to AA-21, Inclusive, and AA-23 to AA-26, Inclusive.

Compliance required prior to November 1, 1947.

To eliminate the possibility of cracks developing in the stabilizer main spar and subspar, the center section of the main spar must be replaced with one having the lower flange-web radius cutout approximately 2 inches from either end. Two 0.064-inch dural channels (404-186053) should be installed between the new attachment fittings (437-186095 and 6) and the main spar web. At the main spar attachment fittings, an 0.032-inch dural doubler (404-186052) should be riveted to the lower skin, the main spar, and the center nose rib flanges.

The forward part of the upper flanges of each stabilizer-fuselage attaching angle should be cut off as far back as the sixth screw hole. The corresponding 12 holes in the stabilizer should beplugged. A three-screw outboard section of the gang nut on each side of the stabilizer subspar should be removed and the corresponding holes in the No. 13 bulkhead angle plugged. The revision of the stabilizer attachment eliminates the necessity for further inspection for cracks except as made during the normal periodic inspection.

(Beech Service Bulletin No. D18C-3 covers this same subject.)