On 17 October 2017, the first prototype (PT-ZNF) made an uncommanded descent from 20000 ft to 3100 ft at 4500 ft/min. In December 2017, as the two prototypes accumulated over 1,500 flight hours and laboratory testing over 40,000 hours, initial operating capability was reached while full operational capability was expected in 2018.
On 17 October 2017, the initial model (PT-ZNF) made an unplanned drop from 20000 ft to 3100 ft at 4500 ft/min. In December 2017, as the two models accumulated over 1,500 flight hours and laboratory testing over 40,000 hours, initial operational readiness was achieved while full operational capability was anticipated in 2018.