The engine costs arose primarily on 380 Trent 1000 "Package C" engines (which entered service in 2013 and account for 78% of the Trent 1000 engines currently in use), and a small number of "Package B" engines (166, which entered service in 2012), with both fitted to the Boeing 787 Dreamliner. This was due to lower-than-expected durability of turbine blades and compressor rotor blades, and the subsequent costs to repair, replace, redesign, and install new parts. Costs have also been incurred due to significant disruption caused to airline customers, including having to cancel flights, modify flightpaths, or switch to different aircraft while engine inspections are carried out. Rolls-Royce continues to make good progress in lowering the number of aircraft on