Aircraft of the ADF – AESL CT-4 Airtrainer

In 1969, an AESL T4 (registered ZK-CJN) flew to Australia for RAAF evaluation. RAAF Air Staff Requirement 67, issued in May 1971, laid down the requirements for a basic trainer to replace the Winjeel, and AESL responded with a development of the Aircruiser, powered by a 210hp (157kW) Continental. Known as the CT-4, the prototype ZK-DGY flew on February 23 1972. The CT-4 was selected by the RAAF over the Scottish Aviation Bulldog, and the order for 37 aircraft was announced in July 1972, at a cost of $3.2 million. The Royal Thai Air Force (RTAF), which had been awaiting the Australian decision, then ordered 24 CT-4s and these were delivered before the RAAF batch.

The first production CT-4A (registered ZK-DIM, AESL constructor’s number 002) was delivered in December 1972 to the Thai Government, followed by the RTAF order (c/n 003 to 026). In 1973, NZ Aerospace Industries (NZAI) was formed by the merger of AESL and Air Parts (NZ) Ltd, manufacturer of the Fletcher FU-24 agricultural aircraft. Production then commenced in 1974 for the 37 NZAI CT-4As of the RAAF (c/n 027 to 063), serialled A19-027 to A19-063.

The first aircraft, A19-027 with NZ ferry registration ZK-DZP, was delivered from Hamilton to RAAF Williamtown on January 7 1975. This aircraft was officially accepted by the RAAF at Bankstown on January 15. Each RAAF CT-4 was ferried across the Tasman with long range tanks, staging through either Norfolk or Lord Howe Islands. Most of the ferries were flown by NZAI Chief Pilot, Cliff Tait, who describes in great detail the hazards and loneliness of long over water single engined crossings in his book Water Under My Wings. Initial deliveries were to Central Flying School, at RAAF East Sale, for instructor conversion, followed in late 1975 with the first basic course at No 1 Flying Training School, at RAAF Point Cook. Also during 1975, a CT-4 of the RAAF’s Aircraft Research and Development Unit (ARDU) completed hot weather trials at Tindal, NT.

The next production batch of fourteen (064 to 077) had been ordered allegedly for a Swiss flying club, but it was discovered in early 1976 that the ultimate customer was the Rhodesian Air Force, then under a United Nations embargo. The New Zealand Government halted export of these aircraft, and they were stored at Hamilton by NZAI. In late 1980, the RAAF arranged to buy this batch to supplement the surviving 35 CT-4s.

Delivered between September 1981 and June 1982, these fourteen aircraft (A19-064 to A19-077) had provision for underwing stores and a higher all up weight capability. The seventh of this order, ZK-EUS (A19-070), was ferried in April by Cliff Tait, to complete his 100th single engined Tasman Sea crossing. The next company to become involved with the Airtrainer design was Pacific Aerospace Corporation (PAC), which was formed in 1982 when NZAI went into receivership. The final production run of the CT-4A was for the RNZAF, and with the last of this batch (serialled NZ1948), deliveries stood at 96 aircraft.

In November 1989, a CT-4 of 1 Flying Training School (A19-040) re-enacted the first transcontinental Australian flight by Captain Henry Wrigley, who had flown a BE-2e biplane from Point Cook to Darwin seventy years previously in 1919. PAC was ultimately to become 75% owned by Aerospace Technologies of Australia (ASTA). Airtrainer production resumed in 1990 with the CT-4B for the civil trainer market, and this type was selected by the BAe-Ansett College (now the Australian Air Academy) at Tamworth, NSW. It is at this school that prospective RAAF pilots undergo flight assessment prior to selection for progression to the RAAF’s PC-9 trainers. Five CT-4B trainers were also delivered to the RTAF during 1992.

A further development of the CT-4 was a 420shp (313kW) Allison 250-B17D turbine powered variant, the CT-4C. PAC also entered the USAF Enhanced Flight Screener competition for a primary trainer with the CT-4E version, powered by a 300hp (224kW) Lycoming, hoping to capture an order for 125 aircraft.

In December 1991, Central Flying School transferred its last Airtrainers to No 1 FTS, as no further CT-4 instructor training was required by the RAAF. As the CT-4 was phased out of 1FTS service at the end of 1992, preparations were made for the aircraft’s disposal to the civil market. Several massed CT-4 farewell flypasts were staged over Melbourne and Sydney during April 1993. This not only marked the aircraft’s retirement from service, but also the end of 78 years of flying training at Point Cook. An in-depth report on this was featured in our August ’92 edition.

Thirty six aircraft were auctioned at Bankstown on May 22 1993, the likes of which had not been witnessed in Australia since the RAAF disposed of its Tiger Moths after World War Two. All aircraft were quickly sold, fetching prices varying between $42,000 and nearly $70,000. Some of these aircraft have been sold overseas, with at least three (A19-035, -044 and -066) passing to the US.

With flight grading for the RAAF and RAN, and basic training for the Army, being transferred to civil contractors, future military pilots will continue to fly the “plastic parrot” via Tamworth’s civilianised CT-4Bs. In addition, with so many of the type now on the civil register, the CT-4 will continue to be enjoyed by the private pilot fraternity. This was ably demonstrated in March this year, when several CT-4s participated in pylon racing at Valleyfield’s Skyrace Tasmania, near Launceston.

Although no longer actively flown by the RAAF, two aircraft – A19-027 and A19-077, the first and the last – have been retained for the RAAF Museum at Point Cook. A third, A19-033, is stored at Wagga for eventual display by the National Aerospace Museum. In addition, those aircraft that have not been sold have been relegated as instructional airframes, for tradesman training at the RAAF Technical Training School (RSTT) at Wagga.

Regarding the current status of the CT-4 aircraft as of January 2026:

Pacific Aerospace Corporation (PAC), the manufacturer mentioned in the text, underwent significant changes, eventually being acquired and reformed as Pacific Aerospace Ltd, and more recently becoming NZSkydive Ltd. The CT-4E variant mentioned in the text as a competition entry eventually saw success, notably with the Royal New Zealand Air Force, which operated a fleet of CT-4Es as their primary trainer until they were replaced by the Beechcraft T-6 Texan II in 2015.

The RAAF Museum at Point Cook continues to maintain A19-027 and A19-077. A19-027 remains a significant part of their collection as the first of the type delivered to the RAAF. On the civil register, the CT-4 remains a popular “warbird” entry for private owners in Australia and New Zealand, frequently appearing at airshows and community fly-ins.