47-21-20 REPUBLIC: (Was Mandatory Note 10 of AD-769-2.) Applies to Model RC-3 Aircraft Serial Numbers 426 Through 484, Except 446, 447, 452, 455, 460, 468, 471, 473, 475, 480, 481 and 483.
Compliance required not later than the next 25 hours of operation subsequent to July 1, 1947, and in any case not later than September 1, 1947.
In order to prevent excessive loss of oil through oil pressure gage line in case of its failure, install a restrictor fitting at the engine end of that line.
(Seabee Service Bulletin No. 13, dated March 17, 1947, covers this same subject.)