ST Aerospace A - 4SU Super Skyhawk The ST Aerospace A - 4SU Super Skyhawk is a major upgrade project of the Douglas A - 4S Skyhawk attack aircraft undertaken by Singapore Aircraft Industries ( SAI , now ST Aerospace ) in the 1980s and was used exclusively by the Republic of Singapore Air Force ( RSAF ) , serving in the fighter - bomber role from 1989 until retirement from front line service in 2005 . Since mid - 1999 , the A - 4SU took on the additional role of being the designated Advanced jet trainer ( AJT ) aircraft for the RSAF ' s AJT training program / detachment in Cazaux , France . Design and development . A - 4S and TA - 4S . Starting in 1973 , the Republic of Singapore Air Force ( RSAF ) began to acquire Douglas A - 4 Skyhawk s for use . The first batch of over 50 airframes ( ex - US Navy A - 4Bs ) was ordered and was subsequently requisitioned from the Military Aircraft Storage and Disposition Center ( MASDC ) at Davis - Monthan AFB , Arizona which was released to the Lockheed Aircraft Service ( LAS ) Company at Ontario , California and its subsidiary Lockheed Aircraft Service Singapore ( LASS ) at Seletar Airfield , Singapore for a major overhaul and refurbishment . These aircraft would later emerge as the A - 4S single - seater ( 44 airframes ) and the TA - 4S two - seat trainer ( three airframes ) , all having more than 100 changes incorporated ( these included a slightly longer nose to house a new avionics package , five stores hardpoint s instead of the usual three , a saddle style Automatic Direction Finder dorsal hump , cockpit armour plating , spoiler s , a cranked refueling probe , AIM - 9 Sidewinder capability , a brake parachute housing below the jetpipe into the standard A - 4B airframes . As with the Israeli A - 4Hs which were armed with a pair of 30 mm DEFA cannon s , these were similarly armed with the ADEN cannon s in place of the original 20 mm Colt Mk 12 cannon s . A later order of four two - seat trainer airframes was placed in 1976 , and these joined the RSAF in 1977 . The TA - 4S trainers were not the standard TA - 4 with a common cockpit for the student and instructor pilot , but were instead rebuilt by Lockheed with a fuselage plug inserted into the front fuselage and a separate bulged cockpit ( giving better all round visibility ) for the instructor seated behind the student pilot . This arrangement was unique for the RSAF but was not the first by Lockheed ( the Lockheed SR - 71B and TU - 2S trainers also used stepped cockpits ) . As such converted / rebuilt airframes , these TA - 4S trainers were powered by the original Wright J65 turbojet engines as used in the B / C models instead of the Pratt & Whitney J52 used by the purpose - built TA - 4E / Fs tandem - seaters from Douglas assembly line ; this was the main reason why the RSAF decided to not procure the TA - 4E / Fs ( if indeed an order was placed ) and then having to maintain two different engines to power essentially the same aircraft type ( a scenario not unlike having a fleet within a fleet ) . All of the single - seaters were later retired when the upgraded A - 4SU began to enter service , however , the twin - seaters were upgraded instead and remained in service . A - 4S - 1 and TA - 4S - 1 . A second batch of 70 airframes was ordered ( mix of ex - US Navy A - 4Bs and A - 4Cs ) in 1980 , these were shipped directly to Singapore for rebuilding with the A - 4Cs being rebuilt as the A - 4S - 1s while the A - 4Bs was to remained in storage for use as spares . Along with a small number of TA - 4S - 1s , these newer Skyhawks ( characterised by its straight refueling probe instead of the cranked refueling probe found on the original A - 4S / TA - 4S ) would join the RSAF as attrition replacements from 1982 . However , these airframes retained the original Colt Mk 12 cannons of the A - 4Cs . In 1983 , a third order of 8 TA - 4S saw 16 stored A - 4Bs from the Aerospace Maintenance and Regeneration Center ( aircraft boneyard ) being converted and rebuilt as the TA - 4S - 1 trainers ( eight airframes ) . A - 4SU and TA - 4SU Super Skyhawk . In 1985 , as a result of four A - 4S being written off in separate accidents , coupled with the low serviceability of the original batch of A - 4S . Investigations conducted by RSAF reveal that although there was plenty of fuselage life left , the Wright J65 turbojet engines in use by the Skyhawks was too old and the associated spare parts were becoming both difficult and expensive to obtain . Consequently , the RSAF decided to upgrade the A - 4S / TA - 4S rather than to replace them . With SAI contracted as the main contractor for the upgrading project and a non - afterburning General Electric F404 - GE - 100D turbofan engine selected as the new engine , the upgrading project would later be extended to cover the entire fleet of newer A - 4S - 1s as well as taking the opportunity to completely modernise the avionics package ( newly installed equipment now included a Pave Penny laser seeker mounted in the nose , an Inertial navigation system ( INS ) , a Tactical Air Navigation ( TACAN ) system , fore & aft Radar warning receiver s ( RWR ) and chaff / flare countermeasure s ) of the aircraft . The modernised A - 4SU and TA - 4SU versions with its new F404 turbofan engine had 29 % more thrust , which resulted in a 30 % reduction in takeoff time as well as an increase in usable payload , range and maximum speed . The maximum speed now at sea level is , and maximum cruise speed at is . Operational history . By 1974 , the RSAF received enough refurbished A - 4S to form the 142 Sqn and 143 Sqn , which were based at Tengah Air Base and Changi Air Base , respectively . In RSAF service , the A - 4S / TA - 4S were given 3 - digit serials starting with 6 ( e . g . 600 , 651 ) . From 1982 A - 4S - 1 and TA - 4S - 1 Skyhawks would join the RSAF as attrition replacements with the balance being allocated in 1984 to form a new unit - 145 Sqn which was also based at Tengah Air Base . These were given 3 - digit serial starting with 9 ( e . g . 900 , 929 ) . In total , approximately 150 airframes ( all A - 4Bs and Cs ) were acquired by Singapore . The modernised A - 4SU Super Skyhawks were received by 143 Sqn first , followed by 142 Sqn and 145 Sqn of the RSAF from 1989 onwards . The type was also operated by the RSAF Black Knights aerobatic display team for precision aerial manoeuvers from 1990 to 2000 . End of front - line service . After 31 years of operations , the RSAF officially withdrew its fleet of A - 4SU Super Skyhawks from operational combat service in Singapore on 31 March 2005 . The A - 4SU ' s achievements included flying directly from Singapore to the Philippines , incorporating the RSAF ' s first air - to - air refueling mission in 1986 , as well as the aerobatic display of the ' red and white ' Super Skyhawks flown by the RSAF Black Knights during Asian Aerospace 1990 , 1994 and 2000 , it was last used by the Black Knights during Singapore ' s National Day Parade held on 9 August 2000 . A month before its retirement , the Skyhawk squadron ( 145 Sqn ) won the top honours in a strike exercise against its more modern F - 16 and F - 5 counterparts and emerged as the Top combat squadron in the Singapore Armed Forces Best Unit Competition , an honour it has held since year 2000 . On 5 October 2005 , one A - 4SU Skyhawk was delivered to Singapore Polytechnic as a teaching aid . Subsequently , Ngee Ann Polytechnic , Temasek Polytechnic and Nanyang Technological University would each receive an A - 4SU Skyhawk as well . Two of the retired A - 4SU Super Skyhawks were also donated to the French Air and Space Museum ( Musée de l ' Air ) for static display . On 12 January 2006 , a Certificate of Transfer and Acceptance signing ceremony took place between representatives of the RSAF and the French Aeronautics Museum at Cazaux Air Base in France . Since then , only " 928 " was put on display in the Rosette Hall of the museum while " 941 " was stored . Secondary role . In 1998 , the French government offered the use of facilities at BA 120 Cazaux Air Base ( France ) . A 25 - year lease for basing rights of 18 A - 4SU aircraft and approximately 250 RSAF personnel and their families was signed later that year . Back in Singapore , 143 Sqn was disbanded in 1997 , and its aircraft were handed over to 150 Sqn , which had given up its SIAI Marchetti SF . 260 basic trainers . The new squadron then took up the role of advanced jet training , using its aircraft as a lead - in fighter trainer for RSAF pilots . This made it the prime candidate for moving to France , and the first of 18 aircraft were " packed " and sent to France by ship in mid - 1999 as part of the RSAF ' s Advanced Jet Training Program . The 11 remaining training aircraft ( 4× A - 4SU and 7× TA - 4SU ) were originally scheduled to retire in 2007 but will remain in service until the delivery of their replacement , the Alenia Aermacchi M - 346 Master , scheduled for 2012 .