Nextant Aerospace G90XT Single-Lever Controls Poised For Certification Nextant Aerospace appears to be on the cusp of certification of new Single-Lever Controls for their G90XT. The power controls are digitally controlled and Nextant hopes to gain validation by the first half of 2017. Basically this validation is the last stepping-stone to having the G90XT fully certified and then eventually pave the way for deliveries to start. It is important to note that the G90XT was certified in late 2015 but the Single Lever controls was still an issue. Just as a reminder, the G90XT is Nextant Aerospace manufacturer twin turboprop of the Beechcraft King Air C90.