The Aero AT-4 is build with compliance to the US Light Sport Aircraft Specification, LSA. It has been approved by EASA to fly in Europe for non-commercial operations. All-metal, semi-stressed skin, low cost and low maintenance aircraft is suitable for economical training and touring. The AT-4 is derived from the AT-3 with the MTOW increased up to 600 kg. The structure has a longer wingspan, altered wing profile and spar, additional winglets and fillets between the wing's leading edge and the fuselage. The AT-4 fuselage, the propeller, the controls and the tricycle undercarriage are of common design with the AT-3 aircraft. The stall speed is reduced to 36 knots in comparison to 44 knots for the AT-3. The AT-4 is equipped with 100 hp Rotax 912 ULS engine.
The AT-4 is approved for Night-VFR. The standard equipment includes a radio, voice activated intercom system, the engine instruments and the traditional Six-Pack of avionics. The antenna and the panel installation are prepared for Garmin 495 GPS. The installation is upgradable to Garmin 496. Many further options like Mode S transponder, the ELT 406, single screen and twin screen Dynon Glass-Panel and the auto-pilot can be offered.