Matching Pairs AVIATION ABBREVIATIONSOnline version Match the abbreviation with the correct meaning. by Steven Rafael Torres Orozco 1 P.S.I 2 LB 3 SRM 4 P/N 5 S/N 6 SB 7 FT 8 SL 9 AD SERIAL NUMBER FOOT PART NUMBER PRESSURE SQUARE INCH SERVICE LETTER SERVICE BULLETIN AIRWORTHINESS DIRECTIVE STRUCTURAL REPAIR MANUAL POUND