The RSAF became an A-4 Skyhawk operator in the early 1970's. There are conflicting reports about how many A-4's the RSAF operated in the end, and the US FY # involved are not a 100% clear either. E.g. 912 shown here is reported to have US FY # 144966 (cn 12212) or 144972 (cn 12218). It started life as a single seat A-4B in 1959, and inserting a 28 inch fuselage "plug" modification made it a dual seat trainer at some point, resulting in the odd looking two bubble canopy unique to the ~20 RSAF TA-4's. The TA-4SU designation came after an upgrade carried out by ST Aerospace in the mid 1980's.