47-10-23 LOCKHEED: (Was Mandatory Note 25 of AD-763-3.) Applies to Model 49 Serials 1975, 1976, and 2021 Through 2059.
Compliance required immediately.
Install AC364-524 steel nuts in place of any AC364-B524 brass nuts which may be installed on bolts through bathtub fittings at wing Station 80 (5 nuts per fitting, 170 nuts per airplane should be checked.
(LAC Service Bulletin 49/SB-42 covers this same subject.)