replaced the 20 mm cannon. The first of two prototypes flew in August 1984. Small numbers were produced. RF-18D Proposed two-seat reconnaissance version for the US Marine Corps in the mid-1980s. It was to carry a radar reconnaissance pod. The system was canceled after it was unfunded in 1988. This ability was later realized on the F/A-18D(RC). TF-18A Two-seat training version of the F/A-18A fighter, later redesignated F/A-18B. F-18 HARV Single-seat High Alpha Research Vehicle for NASA. High angles of attack using thrust vectoring, modifications to the flight controls, and forebody strakes X-53 Active Aeroelastic Wing A NASA F/A-18 has been modified to demonstrate the Active Aeroelastic Wing technology, and was designated X-53 in December 2006. Export variants These designations are not part of 1962 United States Tri-Service aircraft designation system. F-18L A proposed land-based export version of the single-seat F-18A with air-superiority and attack capabilities. This variant was to be lightened by the removal of carrier landing capability and assembled by Northrop. Customers preferred the standard Hornet and the F-18L never entered mass production. (A)F/A-18A/B (A)F/A-18A: Single-seat fighter/attack version for the Royal Australian Air Force. (A)F/A-18B: Two-seat training version for the Royal Australian Air Force. "F/A-18A" was the original company designation, designations of "AF-18A" & "ATF-18A" have also been applied. Assembled in Australia (excluding the first two (A)F/A-18Bs) by Aero-Space Technologies of Australia (ASTA) from 1985 through to 1990, from kits produced by McDonnell Douglas with increasing local content in the later aircraft. Originally the most notable differences between an Australian (A)F/A-18A/B and a US F/A-18A/B were the lack of a catapult attachment, replacing the carrier tailhook with a lighter land arresting hook, and the automatic carrier landing system with an Instrument Landing System. Australian Hornets have been involved in several major upgrade programs. This program called HUG (Hornet Upgrade) has had a few evolutions over the years. The first was to give Australian Hornets F/A-18C model avionics. The second and current upgrade program (HUG 2.2) updates the fleet's avionics even further. By 2021 12 (A)F/A-18A and 6 (A)F/A-18B (and an additional 7 broken down (A)F/A-18 for spare parts) were sold to the Royal Canadian Air Force. CF-188 CF-188A: Single-seat fighter/attack version for the Canadian Armed Forces (CAF)/Royal Canadian Air Force (RCAF). Unofficially referred to as the CF-18A Hornet. CF-188B: Two-seat training and combat version for the CAF/RCAF. Unofficially referred to as the CF-18B Hornet. EF-18 Hornet EF-18A: Single-seat