AD 47-42-10

47-42-10 DOUGLAS: (Was Mandatory Note 7 of AD-781-1.) Applies to the Following DC-6 Airplanes: Serials 42854 Through 42887, Inclusive, and Serials 43000, 43001 and 43055.

To be accomplished not later than January 1, 1948.

Some operators have experienced malfunctioning of the DC-6 landing gear antiretract mechanism, thereby preventing retraction of the landing gear. Pending redesign of the antiretract mechanism of the landing gear control valve assembly, P/N 3319922, the antiretract mechanism may be permanently disconnected if desired, however, if connected, it must be revised in accordance with this note.

In order to correct this unsatisfactory condition, which is due to slippage and lost motion in the antiretract cable system, it is necessary to accomplish the following:

1. Remove clamp P/N 1338701 from Arens down-lock control cable assembly, P/N 4334802. Install 21-inch dural tube, P/N 1356157, around lower end of the Arens control cable (the upper end of the tube should be flanged). Install AN 735-7 clamp at lower end of tube. (Prior to installing dural tube push 4-inch (7/16 I.D. x 9/16 inch O.D.) synthetic rubber tube over lower end until it clears sufficiently to allow installation of clamp below it.)

On upper end of dural tube, P/N 1356157, install trunnion, P/N 1356154, which incorporates a bushing, P/N B-162-0688, and clips, P/N 1356156. Attach this assembly to the wheel well cover plate stiffener approximately 21 3/8 inches below upper end of cover plate.

Remove down-lock control cable clamp, P/N 1340559, located 4 1/16 inches from Station 114.5 and install new clamp, P/N 1356158, on angle, P/N 5249561-366, 1 1/16 inches from Station 114.5.

(Douglas Drawing 5334338, Change "H" covers this modification.)

2. To correctly adjust the landing gear down-lock mechanism in order to maintain the required load of 100 pounds on the cable number 108 with the oleo fully extended, the oleo should be fully retracted into the shock strut cylinder and then permitted to fully extend, at least 8 to 10 times, checking and maintaining the 100-pound load after each operation.

(Douglas Drawing 7354206, page 28, covers this same subject.)