Capabilities of the FAM-C method to diagnose the accessory gearboxes and transmission -train assemblies of the MI-24 helicopters

The study has been intended to present some selected service-imposed issues with the transmission system of the Mi-24 combat helicopter. An attempt has been made to present predictions about possible threats/hazards to the transmission system of this helicopter. The forecast has been based on the FAM-C analysis of changes in instantaneous frequency against time and, to some extent, on mechanical measurements of disassembled structural components/subassemblies. The greatest emphasis has been laid on capabilities to identify and diagnose locations in structural components of the Mi-24 helicopter (where many and various hazards may arise) using the non-destructive diagnostic method FAM-C developed at ITWL (Air Force Institute of Technology). The method has been based on the tracking of parameters of modulation of airborne alternator produced frequencies. The testing requires no extra sensors, since the built-in airborne AC, DC, and tachogenerators themselves are the diagnostic transducers. While taking FAM-C measurements, the transmission system experiences no extra loads or rotational-speed distortions.