components of the rotating assembly are identified as engine parts having an impact of the service life of the disc 20 as shown in fig1 the disc 20 and associated influencing parts i e the blades 22 the hardware 24 are assigned a single assembly part number p n 26 the assembly p n 26 is then defined as the u201c critical u201d part and assigned an lcf life in use cycles on the critical assembly p n 26 are counted once the lcf limit is reached the rotating assembly p n 26 must be removed from the engine while the disc must be replaced the existing blades and hardware may be re used if suitable to do so repair or replacement to sub components e g blades blade retainers etc of the assembly must be substantiated relative to the assembly p n 26 rather than merely to the corresponding sub component previously present on in the assembly as shown in fig2 life limit values are preferably provided in the airworthiness limitations section of the ica preferably additional cautions are also provided to the operators and maintenance personnel such as by including a notice that the given life limit value is only valid for the disc 20 when operated as a component of the rotating assembly designated by p n 26 in this example a detail part number is attributed to the disc 20 in addition to the p n attributed to the rotating assembly alternatively no detail part number may be attributed to the disc 20 and the critical part is instead designated only by the rotating assembly part number 26 either way the operator and maintenance personnel are expressly made aware of the fact that changes to individual components of the assembly may affect the service.