AD 47-42-08

47-42-08 DOUGLAS: (Was Mandatory Note 5 of AD-781-1.) Applies to DC-6 Airplane Serial Numbers 42854, 42855, 42857, 42858, 42860 to 42865, Inclusive; 42867, 42869 to 42880, Inclusive; 42882 to 42891, Inclusive; 43000, 43001, 43003 to 43009, Inclusive; 43055 and 43056.

To be accomplished not later than next No. 3 inspection (or not later than next 150 hours for non-air-carrier operations).

Certain cases have been found wherein the 5240452 horizontal stabilizers do not have the rivet pattern specified on Drawings Nos. 5248752 and 5249045. The following specific cases should be inspected and rivets should be added if the numbers are less than the following:

Referring to Drawing 5248752 "Horizontal Stabilizer Rear Spar Assembly", zone 4, directly outboard of Station 63: 1. There should be at least 12 AD5 rivets top and bottom through the web and cap between the -14 and -12 stiffeners, not counting those through the stiffeners. 2. There should be at least 4 AD5 rivets through the -68 doubler, spar web and spar cap. 3. There should be at least 6 AD5 rivets top and bottom between the -12 stiffener and the -68 doubler through web and cap.

With reference to Drawing No. 5249045 "Horizontal Stabilizer Panel and Spar Structure Assembly" zone 3, section L-L, directly inboard of Station 69.5 both top and bottom, the existing rivet pattern of either 1/8 or 5/32 rivets should be continued inboard with AD5 rivets using the present pattern of 3/4 inch O.C. to within 3 1/16 inches from the end of the spar cap. Existing 1/8-inch rivets are satisfactory.

It should be noted that the foregoing inspections and riveting can be accomplished without removing the elevators.

(Douglas Service Letter A-214-529.010/RLT, and attached sketches, dated July 14, 1947, covers the same subject.)