Used on outboard wing. 3a 1st end bulkhead thread class 14 1st end bulkhead thread quantity per inch rigid, center wrenching facility unjs 1st end bulkhead thread series
2a external thread class right-hand external 0.460" overall length 7/16-20unf; 0.560 in dia; 0.460 in. hgt; 0.190 in hex head socket; o-ring per MS28778-3 passivate surface treated plug, machine unf external thread series