Pennisetum purpureum \u2018Prince\u2019 is a semi-dwarf, purple-foliaged napiergrass. A change in the frequency response of a sensing circuit is triggered by a sensed or evoked event to make it less sensitive to the detection of a subsequent event for a period of time. In order to assemble or dress the gas turbine engine 10, the rigid raft assemblies can be pre-prepared to incorporate at least a part of at least one gas turbine engine systemcomponent before being installed on the gas turbine engine 10.