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