The Grob 109B and Scheibe SF36a were subject to a pre-view assessment at A&AEE in 1989 against a Specification issued in December 1988. The Grob was considered to be by far the better aircraft. (not helped by Slingsby presenting the Scheibe in a less than presentable state. Following that Vigilants were delivered in 1990 with Initial CA Release being issued in March 1990.