The U.S. Army Aviation Engineering Directorate, Propulsion Drive Systems Branch, has identified the need to replace the antiquated, differential mechanical pressure switch/indicator currently being used in hydraulic system filter applications on all Army helicopters, in favor of newer technology, MEMS based, piezoresistive, solid-state differential pressure transducer with temperature sensing combination for the added benefit of performing self diagnostics and prognostics capabilities to increase aircraft maintainability. The current mechanical design dates back 40 years, does not have temperature sensing capabilities, is incapable of processing information, or from being used for diagnostics and prognostics purposes for condition based maintenance, and its inherent configuration makes it unreliable and problematic for users in the field, resulting in numerous false readings and premature component removals. In support of this effort, based on discussions with the U.S. Armys Aviation Engineering Directorate, Benz Airborne is proposing to develop a multi-platform concept for a diagnostic and prognostic measurement system (DPMS) that, if successful, could be used on all Army helicopters. The Propulsions Drive Systems Branch envisions this pressure transducer with temperature sensor capability, to be a drop in, stand alone replacement for the current mechanical switch. In addition, the pressure sensor shall have provisions for recording data through either a remotely located black box, or electronics incorporated into the head of the transducer, for performing diagnostics and prognostics capabilities. The DPMS will be completely autonomous with no electrical connectors to the vehicle. The DPMS will provide both visual presentation of hydraulic system health (e.g. lights) and recording of the pressure/temperature history. Recorded data shall be retrieved by maintenance personnel using either wireless or wired data link as desired. It is important to note that this pressure sensing device is to be used as a maintenance tool only, and that, it is not intended for pilot usage.
Keywords: Condition Based Maintenance, Diagnostics, Prognostics, Fluid Filters, Mems Sensor, Hydraulics, Differential Pressure Sensor, Failure Indicators
