 In December 2018, the CH-53K was projected to not be ready for combat as expected in late 2019, due to delivery delays caused by technical flaws found in testing, which resulted in a major program restructuring.Flaws included the engine re-ingesting exhaust gas, limited service life for the rotor gear boxes, late deliveries of redesigned parts, and deficiencies with the tail rotor and driveshaft.It is estimated that the delay will push back delivery of combat-ready CH-53Ks until May 2020.