 The first prototype, (registered "D-KBGF"), flew for the first time on 14 March 1980.The G 109A was fitted with a 2,000 cc Limbach Flugmotoren flat four engine (maximum power delivered at 3,400 rpm), and the wing span was increased to .The spare engine power available was marginal in hot atmospheric conditions or when flying through rain, so around 30 G 109A airframes were fitted with a 2,400 cc Limbach engine and an electrically controlled variable-pitch propeller.