47-21-15 REPUBLIC: (Was Mandatory Note 5 of AD-769-2.) Applies to Model RC-3 Aircraft Serial Numbers 488 to 602, Inclusive.
Compliance required as soon as possible, but not later than July 1, 1947.
Inspect the radio filter mounted on left-hand rear engine baffle. Filters in steel boxes 4 inches by 2 inches should be further inspected and reworked or replaced as described below, in order to minimize the possibility of a short circuit. Those filters which are in a smaller box need not be reworked.
1. If the coil is bolted to the box and the condenser is fastened in place with a clamp, the filter is satisfactory. If the coil is bolted to the box but the condenser is glued in place, the filter may be used provided a 1 1/8-inch diameter clamp is added to fasten the condenser in place.
2. Filters in which the coil is not bolted to the box should be replaced by a new filter assembly, Republic P/N SK-17-83053-1.
(Republic RC-3 Seabee Service Bulletin No. 15 dated April8, 1947, covers this same subject.)