the a check is scheduled after 850 flight hours: the check originally took 5 hours and has since been reduced to less than 3 hours, within an 8 hour shift. c check are scheduled after 8,500 hours – translating to about 3.5 years of operation. based on experience since product launch, a-checks intervals could increase to 1,000 hours and c-checks to 10,000 hours toward the end of 2019. by september 2017 end, the fleet had undergone 20 a-checks with no findings.